tag:theconversation.com,2011:/uk/topics/antihistamines-7390/articlesAntihistamines – The Conversation2023-02-10T13:52:08Ztag:theconversation.com,2011:article/1983722023-02-10T13:52:08Z2023-02-10T13:52:08ZA nagging cough can hang on for weeks or months following a respiratory illness – and there is precious little you can do about it<figure><img src="https://images.theconversation.com/files/508687/original/file-20230207-744-b34d8v.jpg?ixlib=rb-1.1.0&rect=70%2C15%2C5122%2C3440&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Relentless coughing after a viral infection can be frustrating and worrisome, but in most cases, coughs resolve over time.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/woman-coughing-into-elbow-while-sitting-in-bed-royalty-free-image/1286871310?phrase=coughing&adppopup=true">The Good Brigade/DigitalVision via Getty Images</a></span></figcaption></figure><p>When was the last time you walked into a public space and didn’t hear someone coughing? After three years of flinching at the sound, it can be disarming to hear so many people coughing – and embarrassing if it’s you. </p>
<p>But take heart in knowing that you’re not alone. A long-lasting cough following illness from an <a href="https://www.health.harvard.edu/staying-healthy/that-nagging-cough#">upper respiratory infection is surprisingly common</a>. And unfortunately, with the rise in <a href="https://theconversation.com/covid-19-rsv-and-the-flu-are-straining-health-care-systems-two-epidemiologists-explain-what-the-triple-threat-means-for-children-194242">seasonal flu, COVID-19 and respiratory syncytial virus, or RVS</a>, there’s been a lot of coughing lately.</p>
<p>A cough is a common symptom of these sorts of respiratory infections, and coughing is a complaint that leads to an estimated <a href="https://www.ncbi.nlm.nih.gov/books/NBK493221/#article-20073.s5">30 million office visits every year</a>. Some 40% of those end up in a <a href="https://scholar.google.cl/citations?hl=en&user=q-s2b08AAAAJ">pulmonologist’s office like mine</a>. </p>
<p>Given how ubiquitous persistent coughing is, you might presume that the medical profession has a long list of treatments that we know work. That, unfortunately, depends on why you are coughing. But a cough following an upper respiratory infection does usually go away, in time.</p>
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<figcaption><span class="caption">Allergies, sinus problems, medications, asthma and bronchitis are among the things that can lead to chronic cough.</span></figcaption>
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<h2>How a cough works</h2>
<p>Doctors have long wondered why the duration of cough varies so much following an upper respiratory viral or bacterial infection. The answer likely lies in differences in people, such as the presence of a condition like asthma or chronic bronchitis. I see this same variability in my office: Some patients develop a long-term cough, while others seem to kick the cough much sooner, with no clear explanation.</p>
<p>Coughing occurs <a href="https://www.ncbi.nlm.nih.gov/books/NBK493221/#article-20073.s5">due to a complex process</a> that begins with an electrical impulse between the nerves within the airways, including the nose and throat. There are two types of nerves that can trigger a cough in response to external stimuli: chemical receptors and mechanical ones called mechanoreceptors. Chemical receptors respond to smells and fumes; they’re the reason people sometimes cough after breathing in spicy peppers sizzling on a hot skillet. Mechanoreceptors respond to sensations from irritants such as dust.</p>
<p>When these nerves are activated, the throat closes and pressure in the chest increases. This buildup of pressure leads to a burst of air and mucous out of the lungs at around 500 mph – a speed <a href="https://www.automoblog.net/top-10-fastest-cars-in-the-world/">nearly twice as fast</a> as the world’s fastest cars. </p>
<p>Studies show that a viral infection <a href="https://doi.org/10.1007%2Fs00408-015-9832-5">alters how sensitive these same nerves are</a>. When you have a viral infection, the resulting <a href="https://theconversation.com/what-is-inflammation-two-immunologists-explain-how-the-body-responds-to-everything-from-stings-to-vaccination-and-why-it-sometimes-goes-wrong-193503">inflammatory process</a> produces a molecule called bradykinin that <a href="https://doi.org/10.1186/s12931-019-1060-8">drives the urge to cough</a>. And it’s known that the virus itself can <a href="https://doi.org/10.1007%2Fs00408-015-9832-5">activate genetic changes</a> that increase the sensitivity of these nerve pathways, which leads to more coughing. </p>
<p>But when the acute stage of infection is over and you start to feel better, the body repairs the damages caused by inflammation in your airways and lungs. Through this process, the cough reflex also abates. And the molecular processes that were making you cough and sneeze more frequently settle down and return to a normal state – at least in most cases. Unfortunately, in some people, this process takes longer than in others.</p>
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<figcaption><span class="caption">She coughed and coughed and coughed. Then a doctor discovered what was wrong.</span></figcaption>
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<h2>Knowing how long is too long to cough</h2>
<p>Doctors find it useful to break respiratory symptoms like cough into specific categories. </p>
<p>There are <a href="https://doi.org/10.1016/j.chest.2017.10.016">three main types of coughs</a>: <a href="http://www.antimicrobe.org/e40.asp">acute, sub-acute and chronic</a>. An acute cough is what most people experience when they’re sick with an active viral infection. A sub-acute cough lingers for <a href="https://doi.org/10.1183/09031936.04.00027804">three or more weeks following an upper respiratory illness</a>. And a chronic cough is one that <a href="https://my.clevelandclinic.org/health/diseases/15048-chronic-cough-overview">persists longer than 12 weeks</a>. Chronic cough is most commonly caused by asthma, <a href="https://www.webmd.com/allergies/postnasal-drip">postnasal drip</a> and, perhaps surprisingly to some, <a href="https://www.mayoclinic.org/diseases-conditions/gerd/symptoms-causes/syc-20361940#">reflux</a>. </p>
<p><a href="https://doi.org/10.1378/chest.129.1_suppl.138s">Postinfectious cough</a> is one variety of sub-acute cough and is the lingering cough that many people have after they get over their respiratory infection. It can last for weeks or months and can progress into chronic cough.</p>
<p>Because postinfectious cough is so common, doctors have long worked to determine how many people have a cough that persists after their other symptoms go away. Those <a href="https://doi.org/10.1378/chest.129.1_suppl.138s">estimates vary among studies</a>. One small study in Japan found that of people who have a sub-acute and chronic cough, <a href="https://doi.org/10.2147%2Fijgm.s8167">12% resulted from a respiratory tract infection</a>. </p>
<p>When it comes to COVID-19, the best evidence to date shows that only 2.5% of the people who have gotten it have also <a href="https://doi.org/10.1007/s00408-021-00450-w">developed a chronic cough</a> after infection. That number may seem small, but it translates to a lot of people coughing, given that the U.S. has <a href="https://covid.cdc.gov/covid-data-tracker/#datatracker-home">more than 280,000 new cases</a> of COVID-19 per week, as of early February 2023. The actual number, though, is unclear because the studies that look at postinfectious cough are often small and only account for the people who got COVID-19 and showed up in their doctor’s office or in a telehealth visit for evaluation.</p>
<h2>No simple fix</h2>
<p>The <a href="https://doi.org/10.1378/chest.129.1_suppl.138S">American College of Chest Physicians</a> and the <a href="https://doi.org/10.1183/13993003.01136-2019">European Respiratory Society</a> have published guidelines to help clinicians navigate these uncertainties and the dearth of data available on the diagnosis and treatment of coughing. Although the U.S. guidelines were published in 2006, they still represent the best evidence available for clinicians and their patients.</p>
<p>About half of patients recover from their cough <a href="https://doi.org/10.1016/j.chest.2017.10.016">without any treatment</a>. For those who don’t, the limited data available <a href="https://doi.org/10.1378/chest.129.1_suppl.95S">suggests that inhalers, steroids, narcotics</a> and certain <a href="https://doi.org/10.1002/14651858.CD001831.pub5">over-the-counter medications may provide relief</a> for some people.</p>
<p>In adults, the evidence for the efficacy of various treatments is mixed and limited. In my practice, I often prescribe a non-narcotic cough suppressant called benzonatate, sold under the <a href="https://www.webmd.com/drugs/2/drug-10992/tessalon-perles-oral/details">brand name Tessalon Perles</a>. It works by numbing the nerves in the lungs and airways, calming the cough reflex. Data for treatments in children is equally lacking, and studies have shown that over-the-counter cough suppressants and antihistamines were <a href="https://doi.org/10.1002/14651858.CD001831.pub5">no more effective than the placebo</a>.</p>
<p>Home remedies can also play an important role for some patients. Many people swear by honey, and there is some limited supporting evidence behind its benefits. One trial showed that honey was more effective at <a href="https://doi.org/10.1002/14651858.CD007094.pub5">soothing a cough than the placebo</a> over a three-day period. </p>
<h2>When in doubt, ask a doctor</h2>
<p>Being worried about a persistent cough is understandable – a quick Google search can present plenty of reasons to worry. Though not a very satisfying answer, most coughs really will eventually resolve on their own. However, if you lose weight rapidly, cough up blood, have night sweats or produce lots of sputum, you should talk to your primary care provider. In rare cases, sub-acute and chronic cough can be <a href="https://www.webmd.com/lung-cancer/lung-cancer-cough">a sign of lung cancer</a> or various forms of chronic pulmonary disease.</p>
<p>If you are simply nervous about it and want more information and advice, that is reason enough to check in with your doctor. After all, a cough is the reason behind millions of office visits every year.</p><img src="https://counter.theconversation.com/content/198372/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kyle B. Enfield receives funding from the National Heart and Lung Institute, Society of Critical Care Medicine - CureID, and the USDA. He is a member of the Society of Critical Care Medicine, the American Thoracic Society, the Society for Health Care Epidemiology of America, and the Wilderness Medicine Society. He is a volunteer with the Boy Scouts of America.</span></em></p>Some coughs can last for weeks or even months following an upper respiratory infection. The good news – albeit not very satisfying – is that most eventually go away on their own.Kyle B. Enfield, Associate Professor of Medicine, University of VirginiaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1232712019-09-27T02:25:29Z2019-09-27T02:25:29ZHow to manage grass pollen exposure this hay fever season: an expert guide<figure><img src="https://images.theconversation.com/files/294008/original/file-20190925-51410-f2ecs2.jpg?ixlib=rb-1.1.0&rect=53%2C0%2C6000%2C3970&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Spring has sprung, which means it's hay fever season.</span> <span class="attribution"><span class="source">From shutterstock.com</span></span></figcaption></figure><p>Nearly <a href="https://www.aihw.gov.au/reports/chronic-respiratory-conditions/allergic-rhinitis-hay-fever/contents/allergic-rhinitis">one in five</a> Australians are affected by <a href="https://www.allergy.org.au/patients/allergic-rhinitis-hay-fever-and-sinusitis">hay fever</a>. If you’re one of the unlucky ones, you’ll know how troublesome the symptoms can be.</p>
<p>Grass pollen is the major outdoor trigger of hay fever and allergic asthma. Pollen grains contain a variety of allergens that can trigger allergic reactions in people who are sensitised to pollen. </p>
<p>The good news is, if pollen is a problem for you, there are things you can do to manage your exposure to it. By adopting some simple tips alongside preventative medications, you may find this hay fever season a little more manageable.</p>
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Read more:
<a href="https://theconversation.com/how-do-you-know-if-your-child-has-hay-fever-and-how-should-you-treat-it-122853">How do you know if your child has hay fever and how should you treat it?</a>
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<h2>What causes hay fever?</h2>
<p>People who are <a href="https://www.nature.com/articles/ng.3985">genetically prone to develop allergies</a> may become sensitised to pollen.</p>
<p>Sensitisation involves development of specific antibodies (called Immunoglobulin E, or IgE) that can bind to the triggering allergen. Repeated exposure to the triggering allergen leads to the activation of inflammatory cells, causing the release of histamine and other mediators. That’s when the symptoms kick in.</p>
<p>An allergic reaction to pollen can lead to hay fever symptoms affecting the upper airways, including itchy, watery eyes, an itchy, inflamed throat, a runny or blocked nose, and sneezing.</p>
<p>Pollen allergy can also lead to what we call allergic asthma – if the allergen components enter deeper into the lungs, this can cause inflammation and symptoms of asthma, like shortness of breath.</p>
<p>While hay fever has long been regarded a trivial condition, it can be <a href="https://medicinetoday.com.au/2015/october/feature-article/hay-fever-%E2%80%93-underappreciated-and-chronic-disease">a serious chronic disease</a> associated with other problems such as sinusitis, sleep disturbance because of nasal blockage, and asthma, leading to fatigue and poor performance at work or school. </p>
<h2>What can you do to reduce exposure to pollen allergens?</h2>
<p>The tragic thunderstorm asthma epidemic of <a href="https://www.thelancet.com/pdfs/journals/lanplh/PIIS2542-5196(18)30120-7.pdf">November 2016 in Melbourne</a> shocked many and elucidated the potential harm of grass pollen exposure. </p>
<p>Lessons from this event illustrate staying indoors with the windows closed reduces risk of experiencing severe symptoms.</p>
<p>Many people affected by thunderstorm asthma recall being outside prior to the passage of the thunderstorm <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/all.13609">across the greater Melbourne region</a> during the late evening of November 21, 2016. </p>
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Read more:
<a href="https://theconversation.com/whats-the-link-between-hay-fever-and-asthma-and-how-are-they-treated-64740">What's the link between hay fever and asthma, and how are they treated?</a>
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<p>Of course, this was an uncommon event, and the majority of people who get hay fever will not experience this level of illness.</p>
<p>On high pollen days, or after thunderstorms in spring, people who are allergic to pollen <a href="https://www.allergy.org.au/patients/allergy-treatment/allergen-minimisation">should stay inside</a> with windows closed when possible. They should also drive with the car windows closed and the air on a setting where it’s circulating, rather than coming in from outside. </p>
<p>Other actions people can take to reduce allergen exposure are to hang washing inside or use a tumble dryer on high pollen days, avoid activities such as mowing the lawn, wear sunglasses outdoors, and shower after activities likely to involve pollen exposure.</p>
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<span class="caption">Close to one in five Australians suffer from hay fever.</span>
<span class="attribution"><span class="source">From shutterstock.com</span></span>
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<h2>A national standardised pollen monitoring network</h2>
<p>For people with hay fever, knowing when the pollen count is likely to be high can be helpful in managing exposure. There are an increasing number of <a href="https://www.melbournepollen.com.au/mobile-app/">mobile apps</a> you can use to monitor the pollen count in your area in real time.</p>
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<img alt="" src="https://images.theconversation.com/files/294274/original/file-20190926-51452-lscnm1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/294274/original/file-20190926-51452-lscnm1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1067&fit=crop&dpr=1 600w, https://images.theconversation.com/files/294274/original/file-20190926-51452-lscnm1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1067&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/294274/original/file-20190926-51452-lscnm1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1067&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/294274/original/file-20190926-51452-lscnm1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1340&fit=crop&dpr=1 754w, https://images.theconversation.com/files/294274/original/file-20190926-51452-lscnm1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1340&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/294274/original/file-20190926-51452-lscnm1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1340&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">A screenshot from pollen monitoring app ‘Melbourne Pollen Count’.</span>
<span class="attribution"><span class="source">Screenshot</span></span>
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<p>In 2016, the National Health and Medical Research Council funded the <a href="https://auspollen.com.au/">AusPollen Partnership</a>. Since its inception, and with the efforts of many researchers, a national standardised pollen monitoring network is being established to help address unmet needs of patients with hay fever and allergic asthma in our community.</p>
<p>The AusPollen Partnership seeded the growth of a number of projects in which pollen monitoring is a key activity; for instance <a href="https://airrater.org/">AirRater</a> in Tasmania and VicTAPS in Victoria. Australian pollen monitoring sites now adopt <a href="https://www.allergy.org.au/hp/papers/australian-airborne-pollen-and-spore-monitoring-network-interim-standard-and-protocols">standard protocols</a> to harmonise pollen monitoring processes so data is comparable between locations. </p>
<p>While expanding the pollen monitoring network, we’ve had the opportunity to evaluate how providing people with local, current daily pollen information helps. </p>
<p>In a pilot study, we found people who didn’t have access to local pollen information indicated a desire to have local pollen information, while people who did have access to pollen information reported it was <a href="https://link.springer.com/article/10.1007%2Fs10453-019-09602-1">very useful</a>. Respondents used pollen information to plan their daily activities, to minimise pollen exposure and to optimise medication use.</p>
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Read more:
<a href="https://theconversation.com/health-check-what-are-the-options-for-treating-hay-fever-48342">Health Check: what are the options for treating hay fever?</a>
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<h2>Preventative medication has an important role</h2>
<p>While minimising exposure to pollen may help reduce symptoms when pollen levels are high, the cornerstone to symptom management and safety during the pollen season is preventative medication like steroid nasal sprays and antihistamines. These can reduce the underlying allergic inflammation and alleviate symptoms of hay fever.</p>
<p>Before the onset of the pollen season, people who are allergic to pollen and suffer from troublesome symptoms should start using medications daily. Control of underlying allergic inflammation in the upper airways is best achieved with nasal sprays containing a topically active steroid. Non-sedating antihistamine tablets and eye drops provide symptom relief (but don’t alter the underlying inflammation). </p>
<p><a href="https://www.allergy.org.au/patients/asthma-and-allergy/thunderstorm-asthma">Seasonal asthma and/or thunderstorm asthma</a> can occur during the grass pollen season in some people with pollen allergy. Those who experience lower airway symptoms during the grass pollen season such as a cough, tight chest, breathlessness or wheeze, should seek medical attention to consider whether they have undiagnosed <a href="https://asthma.org.au/about-asthma/how-we-can-help/first-aid/">asthma</a>.</p>
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<a href="https://theconversation.com/thunderstorm-asthma-whos-at-risk-and-how-to-manage-it-86397">Thunderstorm asthma: who's at risk and how to manage it</a>
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<p class="fine-print"><em><span>Janet Davies receives funding from The National Health and Medical Research Council, Australian Research Council, National Foundation for Medical Research Innovation, Emergency Medicine Foundation, Bureau of Meteorology, Victorian Department of Health and Human Services as well as co-sponsorship from Abionic Switzerland, Stallergenes Australia, Asthma Australia iwth in kind co-contributions from Australasian Society for Clinical Immunology and Allergy, CSIRO, Bureau of Meteorology,and Federal Office of Meteorology and Climatology MeteoSwiss, Switzerland. She is an inventor of patents assigned to QUT granted in Australia, allowed in USA and two applications pending examination. Prof. Davies’s institute has received Honorarium payments and travel expenses for education sessions and conference presentations from Stallergenes Australia, GlaxoSmithKliene, Wymedical, and Meda Pharmaceuticals. </span></em></p><p class="fine-print"><em><span>Connie Katelaris is a principal investigator on an NHMRC partnership grant for AusPollen Partnership. Dr Katelaris is also principal investigator on clinical trials in severe allergic asthma sponsored by Sanofi and Novartis. She receives honorarium for advisory board participation in Seqirus.</span></em></p><p class="fine-print"><em><span>Danielle Medek does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations.</span></em></p>If you get hay fever, minimising your exposure to grass pollen is likely to be useful. Fortunately, it’s becoming easier to keep track of the pollen count. But what do you do when it’s high?Janet Davies, Professor, Queensland University of TechnologyConnie Katelaris, Professor of Immunology and Allergy, UWAS & Head of Unit, South Western Sydney Local Health DistrictDanielle Medek, Physician trainee, researcher, Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1023432018-09-18T20:34:28Z2018-09-18T20:34:28ZI can’t sleep. What drugs can I (safely) take?<figure><img src="https://images.theconversation.com/files/236593/original/file-20180917-177935-1k5b32x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">There are many pharmacological options available for insomnia. But they will mostly make you reliant upon them for sleep. </span> <span class="attribution"><span class="source">from www.shutterstock.com</span></span></figcaption></figure><p>If you’re having trouble sleeping, <a href="https://theconversation.com/some-reasons-why-you-should-avoid-sleeping-pills-10054">medicines</a> shouldn’t be your first option. Exercise regularly, cut back on coffee (and other caffeinated drinks) after midday, eat less in the evening, ease up on “screen time” before, and in, bed, practise meditation and try to have a quiet, dark bedroom dedicated mostly to sleep.</p>
<p>But what if you’ve tried everything and are still struggling with sleep? Many people will want to turn to a medicine for help. Navigating the various options for effectiveness, safety and the potential to become habit-forming can be difficult.</p>
<p>Long-term regular use of medicines to promote sleep should be avoided, as initial effectiveness declines rapidly over a few weeks and dependence and adverse effects become <a href="https://www.nejm.org/doi/full/10.1056/NEJMra1611832">problematic</a>. But in the short <a href="https://www.nps.org.au/australian-prescriber/articles/the-management-of-insomnia-an-update">short term</a>, sleep medications do have their place. Unfortunately they are often <a href="https://link.springer.com/content/pdf/10.1007%2Fs40271-016-0182-z.pdf">over-used, especially in older</a> people.</p>
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Read more:
<a href="https://theconversation.com/why-getting-enough-sleep-should-be-on-your-list-of-new-years-resolutions-88007">Why getting enough sleep should be on your list of New Year's resolutions</a>
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<h2>Benzodiazepines</h2>
<p>Benzodiazepines are drugs such as <a href="https://theconversation.com/weekly-dose-valium-the-safer-choice-that-led-to-dependence-and-addiction-59824">Valium</a>, also used to treat anxiety. They are the most commonly prescribed <a href="https://www.nps.org.au/australian-prescriber/articles/management-of-benzodiazepine-misuse-and-dependence-5">sleeping pills</a>.</p>
<p>Their effects, which include some muscle relaxing properties, are achieved by enhancing the effect of <a href="https://www.wikiwand.com/en/Gamma-Aminobutyric_acid">GABA</a>, an inhibitory neurotransmitter operating throughout the brain. Rarely, some people experience the opposite and become over-excited and more anxious. </p>
<p>As benzodiazepines depress brain function (they depress the central nervous system), their effects add to other central nervous system depressants including alcohol, sedating antihistamines and opioid analgesics such as oxycodone (<a href="https://www.healthdirect.gov.au/endone">Endone</a>). This can be very dangerous, and when combined can lead to respiratory failure, coma and even death.</p>
<p>Physiological and psychological dependence on the drug can develop after only a few days in some people, or weeks in most. Unfortunately, far too many people are <a href="https://www.nps.org.au/news/benzodiazepine-dependence-reduce-the-risk">dependent</a>. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/weekly-dose-valium-the-safer-choice-that-led-to-dependence-and-addiction-59824">Weekly Dose: Valium, the 'safer choice' that led to dependence and addiction</a>
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<p>Importantly, the effectiveness for inducing sleep wears off after a few weeks. It can be very hard to stop taking benzodiazepines as insomnia and often anxiety returns. The duration of “<a href="https://theconversation.com/weekly-dose-valium-the-safer-choice-that-led-to-dependence-and-addiction-59824">withdrawal</a>” is related to the length of time these are taken.</p>
<p>Stopping suddenly after long-term use can be dangerous, with violent withdrawal reactions possible, including epileptic seizures. <a href="https://theconversation.com/weekly-dose-valium-the-safer-choice-that-led-to-dependence-and-addiction-59824">Ceasing</a> these medicines needs to be managed by your doctor. Essentially, a gradual reduction in dose is needed with support and counselling to assist with the temporary increase in insomnia and perhaps anxiety.</p>
<p>Side effects include a “dulling” of cognitive function, memory impairment and the increased risk for accidents, especially unsteadiness and falls in older people. </p>
<p>Benzodiazepines should only be used for two to four weeks, or intermittently, and only in addition to <a href="https://www.nps.org.au/medical-info/consumer-info/how-to-sleep-right">good sleep hygiene</a> (that is, practising the measures listed in the first paragraph).</p>
<p>Temazepam (brand names Normison, Temaze, Temtabs) and lorazepam (brand name Ativan) are reasonable choices from the many benzodiazepines available. That’s because they have a faster onset and short duration of effect so as to avoid a “hangover” the next day.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-how-to-soothe-yourself-to-sleep-83154">Health Check: how to soothe yourself to sleep</a>
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<h2>Z-drugs (hypnotics)</h2>
<p>Zopiclone (brand names Imovane and Imrest) and zolpidem (brand name Stilnox) are similar in their pharmacology and effects to the benzodiazepines. These prescription-only medicines also enhance the actions of GABA to depress brain activity and have the same hazards related to excessive sedation and dependence. </p>
<p><a href="https://www.tga.gov.au/alert/zolpidem-stilnox">Bizarre</a> behaviours and symptoms, for example hallucinations and sleep-walking that can be dangerous, are more likely than with benzodiazepines.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/236595/original/file-20180917-177947-18nirlm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/236595/original/file-20180917-177947-18nirlm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/236595/original/file-20180917-177947-18nirlm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/236595/original/file-20180917-177947-18nirlm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/236595/original/file-20180917-177947-18nirlm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/236595/original/file-20180917-177947-18nirlm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/236595/original/file-20180917-177947-18nirlm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/236595/original/file-20180917-177947-18nirlm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Medications for sleep can’t be used long term.</span>
<span class="attribution"><span class="source">from www.shutterstock.com</span></span>
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<h2>Antihistamines</h2>
<p>Older antihistamine medicines, now known as sedating antihistamines, induce drowsiness through their central nervous system-depressing properties. These are available over the counter from pharmacies. Common examples include diphenhydramine (brand name Unisom Sleep Gels), doxylamine (brand name Restavit) and promethazine (branded Phenergan). </p>
<p>Especially in those with allergies such as hay fever disturbing their sleep, these may be a reasonable short-term option. Dependence on these medications to sleep is a hazard. </p>
<p>These medicines have <a href="https://www.veteransmates.net.au/VeteransMATES/documents/module_materials/M39_TherBrief.pdf">side effects</a> including dry mouth, blurred vision, constipation, confusion, dizziness and urinary retention in men with prostrate problems. All side-effects are worse in older people.</p>
<p>By contrast, over-the-counter antihistamines commonly used to treat hay fever (such as brand names Telfast, Zyrtec and Claratyne) are non-sedating, and therefore not likely to make you drowsy.</p>
<h2>Analgesics</h2>
<p>Any opioid-containing medicine, all now requiring a prescription, will induce drowsiness (depending on the dose) because they also depress our central nervous system. Codeine (in Panadeine, Panadeine Forte or Nurofen Plus), tramadol, tapentadol, morphine or oxycodone will make us sleepy, but they’re not recommended to treat insomnia. </p>
<p>These powerful medicines are best reserved for judicious use in pain relief, given the severe <a href="https://www.mja.com.au/journal/2011/195/5/prescription-opioid-analgesics-and-related-harms-australia">hazards of dependence and overdose</a>. Older people are more sensitive to the central nervous system-depressing effects and also to constipation.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-five-ways-to-get-a-better-nights-sleep-43700">Health Check: five ways to get a better night's sleep</a>
</strong>
</em>
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<h2>Melatonin</h2>
<p>Our sleep-wake cycle is dependent on the hormone melatonin released cyclically from a gland in our brain. <a href="https://www.nps.org.au/radar/articles/melatonin-prolonged-release-tablets-circadin-for-primary-insomnia-in-older-people">Melatonin</a> administered orally helps induce sleep in some people, but is <a href="https://www.nps.org.au/australian-prescriber/articles/melatonin">not as effective as other sedatives</a>.</p>
<p>However, a <a href="https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1002587">recent Australian study</a> tested melatonin in people with sleep problems caused by delayed melatonin release in their brains. These people have trouble falling asleep and waking at times appropriate for proper functioning.</p>
<p>Taken one hour prior to bed time, melatonin (0.5mg) accompanied by a behavioural intervention (such as learning how to meditate) helped the participants get to sleep and improved common accompanying impairments such as low mood, anxiety and difficulty concentrating. </p>
<p>You need a <a href="https://tga-search.clients.funnelback.com/s/search.html?query=melatonin&collection=tga-artg&start_rank=1">prescription for melatonin</a> in Australia. It’s best to avoid alcohol as it interferes with sleep, thereby reducing any effect of melatonin. It is worth trying as it is generally well tolerated, although some people experience back pain. It may work in other types of sleep disturbances, not due to delayed release of melatonin. A dose of 2mg, controlled release one to two hours before bedtime is <a href="https://www.nps.org.au/radar/articles/melatonin-prolonged-release-tablets-circadin-for-primary-insomnia-in-older-people">most commonly</a> used.</p>
<h2>Antipsychotics</h2>
<p><a href="https://www.nps.org.au/australian-prescriber/articles/concerns-about-quetiapine-3">Antipsychotic medicines</a> (such as quetiapine) have been increasingly used to treat insomnia. </p>
<p>Typically used at a lower dose, quetiapine can induce sleep but carries a significant burden of possible harmful effects. These include a fast heart rate, agitation, <a href="https://www.nps.org.au/australian-prescriber/articles/concerns-about-quetiapine-3">low blood pressure and unsteadiness</a>. These make quetiapine not appropriate for treating common sleep problems.</p>
<h2>Antidepressants</h2>
<p>Antidepressants are typically prescribed at a low dose for insomnia, but the supporting <a href="https://www.ncbi.nlm.nih.gov/pubmed/29761479">evidence</a> of efficacy (despite the wide use) is low quality and there is the <a href="https://www.nps.org.au/medical-info/consumer-info/antidepressant-medicines-explained?c=antidepressant-medicine-side-effects-a38bd490">risk of adverse effects</a> such as confusion, dry mouth and blurred vision.</p>
<h2>Herbal and complementary medicines</h2>
<p>Herbal remedies such as valerian, lavender, passiflora, chamomile, hops and catnip are widely promoted to promote “sleep health”. Research to support their efficacy is <a href="https://www.ncbi.nlm.nih.gov/pubmed/20965131">limited</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/is-it-possible-to-catch-up-on-sleep-we-asked-five-experts-98699">Is it possible to catch up on sleep? We asked five experts</a>
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<p>Many <a href="https://www.ncbi.nlm.nih.gov/pubmed/29487083">newer and emerging medicines</a> are being tested for insomnia, so in the future more options should be available. </p>
<p>For now it’s important to remember none of the options listed above is without side effects, and most will cause dependence if used long term, meaning falling asleep without them will be even harder than it was before. </p>
<p>Improve your sleep hygiene, and if that hasn’t worked for you, speak with your doctor about what’s keeping you up at night. She’ll be able to prescribe the best type of medication for you to use in the short term.</p><img src="https://counter.theconversation.com/content/102343/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>With so many different types out there, it’s hard to know what sleep medications are safe to use. Here’s a guide.Ric Day, Professor of Clinical Pharmacology, UNSW SydneyAndrew McLachlan, Head of School and Dean of Pharmacy, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/483422015-10-19T02:55:17Z2015-10-19T02:55:17ZHealth Check: what are the options for treating hay fever?<figure><img src="https://images.theconversation.com/files/98592/original/image-20151016-30741-1rh401e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Ouch.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/hellyeahphotography/5317611080/">Dominik Moser/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span></figcaption></figure><p>If you’re one of the <a href="http://www.aihw.gov.au/allergic-rhinitis/">15% of Australians</a> who experience hay fever, you might have spent the last few weeks sneezing, itching and trying to control a runny nose and <a href="http://www.ncbi.nlm.nih.gov/pubmed/24274227">cloudy head</a>. </p>
<p>Seasonal hay fever is usually <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3320540/">caused by</a> pollen from trees, grasses and weeds. In Australia, the <a href="http://espace.library.uq.edu.au/view/UQ:310691">major triggers</a> are spring-flowering grasses such as ryegrass, but also summer-flowering Bahia, Bermuda and Johnson grasses.</p>
<p>So what’s the best way to <a href="http://www.allergy.org.au/patients/allergic-rhinitis-hay-fever-and-sinusitis">manage your symptoms</a> with medication? </p>
<h2>Decongestants</h2>
<p><a href="http://www.nps.org.au/medicines/ear-nose-mouth-and-throat/nasal-decongestants">Nasal decongestant</a> sprays are effective for unblocking noses. They work very quickly by constricting the blood vessels in the lining of the nose. They’re also useful for opening the nasal passages to allow better access for other, more long-term nasal sprays, which we’ll discuss below. </p>
<p>But beware – they can’t be used for more than a few days before they cause “rebound” problems, where the nose becomes even more blocked. </p>
<p><a href="http://www.webmd.com/drugs/2/drug-95022/adult-nasal-decongestant-oral/details">Oral decongestant</a> tablets aren’t as effective as nasal sprays. They’re most commonly used in combination with antihistamines. Together, these two drugs tackle most of the symptoms of hay fever. </p>
<p>Oral decongestants, such as pseudoephedrine, don’t cause rebound symptoms. But they’re stimulants and have unpleasant side effects such as sleep disturbance, irritability, raising blood pressure and urinary retention. So they’re for short-term use only.</p>
<h2>Antihistamines</h2>
<p>Antihistamines are the most commonly used over-the-counter medications. They’re very effective for alleviating itchy, runny noses and sneezing. But they’re less effective for blocked noses, which in the longer term, becomes the most prominent symptom. </p>
<p>There are two major classes: the older, sedating drugs, such as Benadryl; and the newer, less- or non-sedating drugs, such as Zyrtec, Claratyne and Telfast. </p>
<p>Sedating antihistamines are generally not recommended for hay fever as they cause problems aside from drowsiness. They have unfortunate interactions with alcohol and some other medications, leading to significant risks when driving or operating machinery.</p>
<p>The non-sedating antihistamines as a class are safe, effective and relatively quick-acting. Most act within one to two hours and have a 12-to-24-hour duration of action. There are no meaningful differences in safety and efficacy between the new antihistamines with active ingredients such as cetirizine, loratidine and fexofenadine.</p>
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<img alt="" src="https://images.theconversation.com/files/98596/original/image-20151016-30715-axb3fi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/98596/original/image-20151016-30715-axb3fi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/98596/original/image-20151016-30715-axb3fi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/98596/original/image-20151016-30715-axb3fi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/98596/original/image-20151016-30715-axb3fi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/98596/original/image-20151016-30715-axb3fi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/98596/original/image-20151016-30715-axb3fi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Take an antihistamine before you come into contact with allergens.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/macleaygrassman/8684415373/">Harry Rose/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<p>Antihistamines work best when used before allergen exposure, if this can be predicted. So, if you’re going bush walking or picnicking on a warm windy spring day, take an antihistamine before venturing out.</p>
<p>Contrary to popular belief, our bodies do not “get used to” antihistamines and their effectiveness does not lessen over time. </p>
<p>Two topical antihistamine sprays are available, both of which are effective and can work more quickly than tablets or syrups. </p>
<p>Antihistamine eye drops can ease the irritation and discomfort of itchy eyes more effectively than antihistamine tablets.</p>
<h2>Nasal steroid sprays</h2>
<p>These are the Rolls-Royce of treatments for hay fever and are especially useful for those experiencing regular or severe symptoms. They will dampen down all the symptoms of hay fever and are particularly good for managing nasal blockage in a safe manner. </p>
<p>A number of different nasal steroid sprays are available, some over the counter. </p>
<p>Because they’re a preventative treatment, they must be used on a daily basis to be effective. Ideally, treatment should start at the very beginning of the hay fever season to stop the development of allergic inflammation in the lining of the nose. They also need to be applied correctly to the nose in order to prevent irritation. </p>
<p>Contrary to popular belief, these are very safe medications despite the name “steroid”. Intranasal steroid sprays are applied and are active in the nose; only the smallest amounts reach the general circulation.</p>
<p>Nevertheless, their use should be monitored in children, particularly if they are also using inhaled corticosteroids as an asthma preventer medication.</p>
<p>The most common side effect of nasal steroid sprays is nasal bleeding. This can occur even if used correctly. </p>
<h2>Immunotherapy (allergy ‘vaccines’)</h2>
<p>Immunotherapy involves administering doses of allergen extracts at gradually increasing doses. The aim is to “re-educate” the immune system to down-regulate the allergic response, reducing allergic symptoms affecting the airways. </p>
<p>This treatment has been available for more than a century, but these days two forms are used: injections and sublingual (under-the-tongue) drops or tablets. This should be prescribed by an allergy specialist who determines the correct “vaccine” for the therapy.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/98597/original/image-20151016-30705-1hec1ch.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/98597/original/image-20151016-30705-1hec1ch.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/98597/original/image-20151016-30705-1hec1ch.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/98597/original/image-20151016-30705-1hec1ch.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/98597/original/image-20151016-30705-1hec1ch.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/98597/original/image-20151016-30705-1hec1ch.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/98597/original/image-20151016-30705-1hec1ch.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Talk to your doctor if over-the-counter treatments don’t work.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/williambrawley/4195919691/">William Brawley/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<p>Immunotherapy is expensive and is typically given for three to four years. However, in the long term, it may be <a href="http://www.ncbi.nlm.nih.gov/pubmed/23375206">more cost-effective</a> than treatments just targeting the symptoms. </p>
<p>Immunotherapy is an <a href="http://www.ncbi.nlm.nih.gov/pubmed/20965551">effective treatment</a> but there is still work to be done in <a href="http://www.ncbi.nlm.nih.gov/pubmed/25744907">refining pollen</a> allergen immunotherapy to optimally cover the spectrum of grasses in Australia.</p>
<p>There are many safe and effective over-the-counter treatments for hay fever symptoms, though some treatments may suit you better than others. If you continue to experience symptoms, talk to your GP about other treatment options.</p><img src="https://counter.theconversation.com/content/48342/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Janet Davies has consulted to Stallergenes, France. Her University has received funding from Stallergenes, Merck Sharpe and Dohme, GlaxoSmithKline for education and/or research purposes and Thermofisher, Abacus ALS, Sullivan Nicolaides Pathology have provided in kind materials or services for her research. Janet Davies is an inventor on a patent and three PCT applications relevant to diagnosis and treatment for pollen allergy.</span></em></p><p class="fine-print"><em><span>Connie Katelaris has received honoraria from pharmaceutical companies Meda and Stallergenes for giving lectures.</span></em></p><p class="fine-print"><em><span>Danielle Medek does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>If you’re one of the 15% of Australians who experience hay fever, it’s likely you’ve spent weeks sneezing, itching and trying to control a runny nose and cloudy head. So, what can you do about it?Janet Davies, Associate professor, Queensland University of TechnologyConnie Katelaris, Professor of Immunology and Allergy, UWAS & Head of Unit, South Western Sydney Local Health DistrictDanielle Medek, Ecophysiologist; junior medical officer, ACT HealthLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/403182015-10-07T19:24:44Z2015-10-07T19:24:44ZWhat are allergies and why are we getting more of them?<figure><img src="https://images.theconversation.com/files/95161/original/image-20150917-7521-3ppdou.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Allergies are becoming more frequent in the western world. </span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/al-stan/3475946574/">Al Fed/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>Allergies are reactions caused by the immune system as it responds to environmental substances that are usually harmless to most people. They may occur in response to a range of different material (called allergens), such as food, pollen, dust mites, animals, insect stings, or medicines.</p>
<p>An allergy can <a href="http://www.allergy.org.au">affect different parts of the body</a>. Allergic rhinitis, or hay fever, for instance, affects the nose and eyes, while eczema affects the skin. Food allergies affect the gut, skin, airways, lungs, and sometimes the entire body through the blood vessels. </p>
<p>Other conditions such as asthma, which affects the lungs, and eosinophilic oesophagitis, which affects the tube from the throat to the stomach, are closely related to allergy. But they have slightly different underlying causes. </p>
<h2>A range of reactions</h2>
<p>While most reactions are only mild to moderate in severity (and can be treated with antihistamines), some can be life-threatening and require emergency medical treatment. The most severe, systemic allergic reactions are known as anaphylaxis. People with known severe allergies should have an <a href="http://www.allergy.org.au">emergency management plan</a> that includes an adrenaline auto-injector for emergency use. </p>
<p>We can confirm whether someone has an allergy by doing a skin-prick testing or a blood test that checks whether their immune system has produced antibodies to an allergen. If the immune system has developed antibodies, it will remember the allergen as a potential threat and is likely to mount a strong immune response on subsequent exposure. </p>
<p>The likelihood of someone having an allergic reaction from future exposures to the allergen is determined by taking their clinical history and these test results into account. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/95141/original/image-20150917-12695-2a4xns.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/95141/original/image-20150917-12695-2a4xns.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=265&fit=crop&dpr=1 600w, https://images.theconversation.com/files/95141/original/image-20150917-12695-2a4xns.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=265&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/95141/original/image-20150917-12695-2a4xns.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=265&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/95141/original/image-20150917-12695-2a4xns.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=333&fit=crop&dpr=1 754w, https://images.theconversation.com/files/95141/original/image-20150917-12695-2a4xns.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=333&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/95141/original/image-20150917-12695-2a4xns.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=333&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Allergic rhinitis, or hay fever, affects the nose and eyes.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/14353437@N06/4515249683/">parrchristy/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>In the case of food allergy, if the probability of an allergic reaction is low, people are given a food challenge. This is when increasing amounts of the offending food are administered while the person is closely observed for any signs of an allergic reaction. Of course, it can result in a reaction.</p>
<p>Allergies are becoming more frequent in Australia and the rest of the western world. <a href="http://www.allergy.org.au/">One in three people in Australia</a> will develop allergies at some time in their life. One in 20 will develop a food allergy and one in 100 will have a life-threatening allergic reaction known as anaphylaxis .</p>
<p>Hospital admissions for anaphylaxis <a href="http://www.ncbi.nlm.nih.gov/pubmed/26187235">doubled in the ten years</a> from 1994 to 2004, and were five times higher in children under five years old over the same period. This suggests the development of allergy in early life is increasing at a faster rate than in adults.</p>
<p>Children are <a href="http://www.abc.net.au/news/2015-07-15/number-of-children-hospitalised-with-food-allergies-on-the-rise/6619752">more likely to develop allergies</a> to eggs, dairy products or peanuts, while adults are more likely to develop an allergy to seafood. </p>
<h2>Possible reasons why</h2>
<p>The reasons for the rising number of allergies are not fully understood, but here are six theories.</p>
<p>1) Decreased exposure to infections or microbes – or both – in early life could lead to an increased risk of allergy. This is commonly referred to as the hygiene hypothesis, <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1838109/">first suggested in 1989</a>. <a href="http://www.ncbi.nlm.nih.gov/pubmed/21060319">Research showing</a> children who have close contact with pets or livestock and those who come from larger families are less likely to develop allergies have indirectly supported the hygiene hypothesis.</p>
<p>2) Delayed introduction of allergenic foods, such as eggs and nuts, until later in childhood could also have an impact. This is one of the most recent theories resulting from the <a href="http://www.nejm.org/doi/full/10.1056/NEJMoa1414850">LEAP study</a>, published in 2015. This randomised trial for early life peanut consumption in a population at increased risk of developing peanut allergies demonstrated that exposure to the nut early in life is protective against developing the allergy.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/95162/original/image-20150917-7517-3j4zx9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/95162/original/image-20150917-7517-3j4zx9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=385&fit=crop&dpr=1 600w, https://images.theconversation.com/files/95162/original/image-20150917-7517-3j4zx9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=385&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/95162/original/image-20150917-7517-3j4zx9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=385&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/95162/original/image-20150917-7517-3j4zx9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=483&fit=crop&dpr=1 754w, https://images.theconversation.com/files/95162/original/image-20150917-7517-3j4zx9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=483&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/95162/original/image-20150917-7517-3j4zx9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=483&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A child with a nut allergy only has a 20% chance of the allergy resolving by the time she reaches adulthood.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/aoifemac/8424630783/">Aoife Mac/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>3) Different methods of preparing foods can <a href="http://www.ncbi.nlm.nih.gov/pubmed/19000582">impact the degree</a> to which they invoke an allergic response; roasting peanuts, for instance, greatly increases allergenicity while boiling reduces it. This may in part explain difference in incidence of in peanut allergy between certain countries.</p>
<p>4) Vitamin D deficiency may increase the risk to develop allergies. Several studies show that the further away you live from the equator (hence your lower level of sunlight exposure, which is needed to make Vitamin D) – or <a href="http://www.abc.net.au/health/features/stories/2013/03/07/3710140.htm">low vitamin D blood levels increase your risk</a> of developing allergies. But the value of vitamin D treatment for preventing allergies has yet to be demonstrated. </p>
<p>5) Allergies may develop after exposure to allergens, such as dairy products or nut oils in skin moisturisers, particularly on inflamed sites, such as eczema.</p>
<p>6) Altered gut bacterial species due to low-fibre diets and widespread antibiotic usage may alter the body’s immune function and create an allergy.</p>
<p>Whether your allergy improves over time often depends on the type of allergy you have. A child with eczema, for instance, will often find her eczema improves by the time she’s a teenager. But some people will have eczema even into their adult years. In contrast, a child with peanut allergy only has a 20% chance of the allergy resolving by the time she reaches adulthood.</p>
<p>While we have treatments for the symptoms of allergy, we do not yet have a cure or the ability to prevent them from developing in the first place. We also don’t have a good test for predicting food allergy, unless we feed the person the suspected food allergen. For now, the best you can do is to manage your allergy.</p><img src="https://counter.theconversation.com/content/40318/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Adam Collison receives funding from the NHMRC, Hunter Children's Research Foundation and the Thrasher Research Fund. He is an inventor on a provisional patent that describes a marker for peanut allergy.</span></em></p><p class="fine-print"><em><span>Joerg Mattes receives/received funding from the National Health&Medical Research Council, the Hunter Medical Research Institute, the Hunter Children's Research Foundation, Asthma Australia, Rebecca L. Cooper Medical Research Foundation. He is a listed inventor on a patent describing a peanut anaphylaxis blood biomarker.</span></em></p><p class="fine-print"><em><span>Rani Bhatia receives funding from the Hunter Children's Research Foundation. She is an inventor on a provisional patent that describes a marker for peanut allergy.</span></em></p><p class="fine-print"><em><span>Elizabeth Percival does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Allergies are reactions caused by the immune system as it responds to environmental substances that are usually harmless. But we don’t yet have a cure or the ability to prevent them from developing.Adam Collison, Post Doctoral researcher - Experimental and Translational Respiratory Medicine Research Group, University of NewcastleElizabeth Percival, Staff Specialist General Paediatrician at John Hunter Children's Hospital, Newcastle, Australia. Conjoint Lecturer & PhD student, University of NewcastleJoerg Mattes, Professor&Chair of Paediatrics | HMRI, University of Newcastle, Australia | Senior Staff Specialist Paediatric Respiratory&Sleep Medicine | John Hunter Children's Hospital, Australia, University of NewcastleRani Bhatia, Senior Staff Specialist in Paediatric Allergy and Immunology at John Hunter Children's Hospital Newcastle NSW Conjoint Lecturer in Paediatrics, University of NewcastleLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/459892015-08-13T05:59:07Z2015-08-13T05:59:07ZAmerica’s most lethal animal<figure><img src="https://images.theconversation.com/files/91513/original/image-20150811-11077-y24j6k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Ouch.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/commissariat/8663013481/in/photolist-ecwd6p-51yKDh-2DzycS-9zeSbD-4mvuu6-agxg4g-6DN4Uu-omETDv-fpAtNx-adwUdV-ae5R9z-br2yJr-6DJhaZ-6DJgNx-6DHUKF-dCBL2t-pH9SzS-bnCEHX-5bEYN3-eHdbUe-51MTX8-buXrgr-2Dzv61-6nEgcQ-6hdJSD-7TSewr-4r5xpj-9h3T1q-e2usn-x9RCyE-ohgkC-6AmNWg-7J1p3S-a6kWkG-bw1hJC-cxHABs-6AqWD5-6QS43x-2QCox4-8Z3ndU-j9X6iZ-bAnT8o-bCWzYR-6UrCD7-2Tco9K-a6uVku-635ozK-a3XVAo-ecCva5-ecCvxy">PROKris Fricke/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>Animal attacks have been in the news a lot. Late last year, a 22-year-old student in <a href="http://www.nj.com/passaic-county/index.ssf/2014/11/hiker_snapped_pictures_of_bear_before_fatal_attack_in_west_milford.html">New Jersey</a> was killed by a black bear he had been photographing. This summer, swimmers off the coast of <a href="http://abc11.com/news/marine-injured-in-8th-shark-attack-along-nc-coast/831239/">North Carolina</a> have suffered a record number of shark attacks, several of which resulted in amputations. And early in July, a 28-year-old <a href="http://www.cnn.com/2015/07/09/us/alligator-involved-in-fatal-texas-attack-is-killed/">Texas</a> swimmer who ignored warning signs was killed by an alligator.</p>
<p>Of course, not all human-killing animals are so large. Each year, dozens of Americans die due to bites by venomous snakes, lizards and spiders. Other small animals such as ticks and fleas, though not naturally outfitted with their own lethal weaponry, can nonetheless kill by transmitting deadly infections, such as <a href="http://www.cdc.gov/powassan/">Powassan virus</a>.</p>
<p>Worldwide, the animal responsible for by far the greatest number of human deaths is just such an insect that transmits a deadly infection: the mosquito. The <a href="http://www.who.int/gho/malaria/epidemic/deaths/en/">World Health Organization</a> estimates that over 600,000 people die each year after being bitten by mosquitoes bearing the deadly malaria parasite. Happily, however, deaths from mosquito-borne diseases are much rarer in the US.</p>
<p>Operating with a biologist’s definition of an animal – an organism with specialized sense organs that responds rapidly to stimuli – one creature has proved to be far more lethal to Americans than all other animal species combined: human beings. Each year in the US, the <a href="http://www.cdc.gov/nchs/fastats/">Centers for Disease Control</a> counts over 16,000 homicides and over 41,000 deaths from suicide and self-inflicted injury.</p>
<p>Yet among nonhuman animals, the creatures that cause more American deaths than any other are bees and wasps. In a <a href="http://www.cdc.gov/niosh/topics/insects/">typical year</a>, nearly 100 American deaths are caused by bee stings. In fact, this number probably represents an underestimate, since some bee sting deaths are erroneously attributed to heart attacks, sun stroke and other causes.</p>
<p>The impacts of bee stings can differ widely. Two weeks ago, a five-year-old girl attending a birthday party in my backyard was stung three times, leading to tears but no permanent damage. Last week, an acquaintance of mine from work, a man in his 50’s with a known allergy to bee stings, lost his life after being stung by a bee.</p>
<p>To the vast majority of people, a bee sting is not life-threatening. <a href="http://www.merckmanuals.com/home/injuries-and-poisoning/bites-and-stings/bee-wasp-hornet-and-ant-stings">Experts</a> say that the average adult can safely withstand more than 1,000 bee stings. Of course, fewer stings could prove dangerous to an infant or small child. What makes stings deadly is generally not the toxicity of bee venom itself but an allergy developed as a result of prior stings.</p>
<p>It is <a href="http://www.webmd.com/allergies/guide/insect-stings">estimated</a> that about two million Americans have allergies to insect stings. Signs of a severe allergic reaction include difficulty breathing, hives, swelling of the face, throat, or mouth, anxiety, rapid pulse, and a drop in blood pressure. Death can result in as little as 10 minutes. Individuals with severe allergies are often advised to carry injectable epinephrine (commonly called an EpiPen), to be administered immediately after a sting.</p>
<p>Anyone who has ever been stung knows how painful it can be. The pain is due primarily to a component of bee venom known as melittin, a small protein that interferes with the normal function of cell membranes. Another component of bee venom, histamine, can cause the affected area to become swollen, red, warm and itchy.</p>
<p><a href="http://www.ncbi.nlm.nih.gov/pubmed/9233664">Some</a> have speculated that melittin may someday be used for therapeutic purposes. For example, it inhibits the bacterium that causes Lyme disease and can suppress the infectious agents involved in a number of sexually transmitted diseases. For the moment, however, most human encounters with melittin are strictly painful.</p>
<p>Some bees cannot sting. Male bees, for example, do not have stingers, which makes sense when you know that a bee’s stinger is in fact a modified form of an organ insects use to deposit eggs. And in most situations, bees are unlikely to attack. Generally they do so only when provoked, such as when a lawn mower disturbs a hive.</p>
<p>One reason bees are disinclined to sting is the fact that, at least among honey bees, doing so often kills the bee. Their stingers are barbed, and the deeper then penetrate into the skin, the more likely they are to become lodged there. When the bee pulls away, it tears away part of its abdomen, typically causing death within minutes.</p>
<p>On the other hand, when the hive is threatened, bees may launch what appears to be a coordinated attack. This is facilitated by the release of alarm pheromones, which attract other bees to the location. Once such an attack commences, they may continue to sting until the offender has left the scene or died.</p>
<p>A routine bee sting requires no specific treatment, although there are a number of approaches that can provide symptom relief. The first order of business is to remove the stinger, in order to limit the amount of venom received. The best way to do this is by scraping it off with a fingernail. Squeezing the sac will only inject more venom.</p>
<p>Generally speaking, it is a good idea to wash the affected area with soap and water. If the hand is involved, rings should be removed prior to the development of swelling. Swelling can be reduced with an icepack and over-the-counter antihistamines, which can also help with itching. Medications such as aspirin or ibuprofen can relieve pain, though it is important to heed their warning labels.</p>
<p>Though bees take the crown as America’s most lethal animal, they are not naturally aggressive creatures, and when they attack, they do so in defense against a perceived threat. The key to avoiding bee stings is to steer clear of hives and nests, operate motorized equipment such as lawnmowers with care and avoid swatting at them when they are in the vicinity.</p><img src="https://counter.theconversation.com/content/45989/count.gif" alt="The Conversation" width="1" height="1" />
Animal attacks have been in the news a lot. Late last year, a 22-year-old student in New Jersey was killed by a black bear he had been photographing. This summer, swimmers off the coast of North Carolina…Richard Gunderman, Chancellor's Professor of Medicine, Liberal Arts, and Philanthropy, IUPUILicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/364812015-05-08T03:45:39Z2015-05-08T03:45:39ZThe low-down on ‘cold and flu’ tablets<figure><img src="https://images.theconversation.com/files/80271/original/image-20150504-2081-1htuo8r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Cold and flu tablets won’t cure a cold.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/_flood_/6414786713">Flood G./Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>Winter is approaching. Your nose is stuffy and you feel a cold coming on. You head to the pharmacy to find an aisle full of cold and flu tablets. </p>
<p>Each year Australians spend more than <a href="http://www.asmi.com.au/media/12687/asmi945_ar_13-14-single_pages_final.pdf">A$500 million</a> on cold and flu medicines. Choosing between the <a href="http://www.tga.gov.au/otc-cough-and-cold-medicines-available-australia">hundreds of different</a> cold and flu tablets available in Australia can be difficult, as each product may contain three or four different medicines. </p>
<p>So, which product is the best one for your symptoms? And will it really help you feel better?</p>
<h2>No cure</h2>
<p>Cold and flu tablets won’t cure a cold. Colds are <a href="https://theconversation.com/health-check-when-is-the-flu-really-a-cold-25150">caused by viruses</a> and symptoms <a href="http://www.nps.org.au/conditions/respiratory-problems/respiratory-tract-infections/for-individuals/conditions/common-cold/for-individuals/symptoms">generally resolve</a> within ten days. Getting plenty of rest and keeping your fluids up may help you feel better.</p>
<p>There is <a href="http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD004976.pub3/abstract">some evidence</a> that combination cold and flu tablets may provide relief from general symptoms in adults but not everyone will benefit. </p>
<p>The small benefits from treatment also need to be weighed up against the risk of side effects and the cost of the medicine.</p>
<h2>How do cold and flu tablets work?</h2>
<p>Cold and flu tablets may contain decongestants, pain relievers, antihistamines and cough suppressants. And tablets marketed for “daytime” symptoms often contain different medicines to “night-time” tablets.</p>
<p><strong>Decongestants</strong> such as <a href="http://www.nps.org.au/medicines/respiratory-system/cough-and-cold-medicines/for-individuals/cough-and-cold-medicines-active-ingredients/phenylephrine-hydrochloride-cough-and-cold-medicines">phenylephrine</a> or <a href="http://www.nps.org.au/medicines/respiratory-system/cough-and-cold-medicines/for-individuals/cough-and-cold-medicines-active-ingredients/pseudoephedrine-hydrochloride">pseudoephedrine</a> may help to relieve a blocked nose. These medicines work by narrowing the blood vessels. The reduction in blood flow reduces swelling and congestion in the nose. </p>
<p>Decongestant tablets can have effects beyond the nose and may exacerbate other medical conditions such as <a href="http://archinte.jamanetwork.com/article.aspx?articleid=765664">high blood pressure</a>, so speak to your pharmacist before taking these medicines. These medicines can also cause sleeplessness, nervousness or dizziness. </p>
<p>In Australia, cold and flu tablets containing phenylephrine can be purchased from the pharmacy or supermarket. Products containing pseudoephedrine can only be supplied after consultation with the pharmacist or on a prescription.</p>
<p>Cold and flu tablets often contain <strong>paracetamol</strong> for relieving aches and pains. Other products marketed for joint pain, headaches, back pain and period pain also contain <a href="http://www.nps.org.au/medicines/pain-relief/simple-pain-reliever-and-fever-medicines/paracetamol">paracetamol</a>, so check labels carefully to avoid taking more than recommended.</p>
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<img alt="" src="https://images.theconversation.com/files/80272/original/image-20150504-2077-hr7fuy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/80272/original/image-20150504-2077-hr7fuy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/80272/original/image-20150504-2077-hr7fuy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/80272/original/image-20150504-2077-hr7fuy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/80272/original/image-20150504-2077-hr7fuy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/80272/original/image-20150504-2077-hr7fuy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/80272/original/image-20150504-2077-hr7fuy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Decongestant tablets can have effects beyond the nose.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/micahrr/5386083144">findingtheobvious/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p><strong>Antihistamines</strong> such as <a href="https://www.nps.org.au/medicines/respiratory-system/cough-and-cold-medicines/for-individuals/cough-and-cold-medicines-active-ingredients/chlorpheniramine-maleate-phenylephrine-hydrochloride">chlorpheniramine</a>, <a href="http://www.nps.org.au/medicines/allergic-disorders/antihistamine-medicines/dexchlorpheniramine-maleate">dexchlorpheniramine</a> or <a href="http://www.nps.org.au/medicines/brain-and-nervous-system/sedatives-and-medicines-for-sleep-problems/doxylamine-succinate">doxylamine</a> may help with allergic symptoms such as sneezing. These medicines work by blocking the effects of histamine in the body. </p>
<p>Antihistamines can cause drowsiness and are often included in “night-time” cold and flu tablets. If your sleep is affected by decongestant tablets, try avoiding the decongestant late in the day or switch to a decongestant nasal spray, rather than taking a tablet containing an antihistamine and a decongestant.</p>
<p>Cold and flu tablets may also contain <strong>cough suppressants</strong> such as <a href="http://www.nps.org.au/medicines/respiratory-system/cough-and-cold-medicines/for-individuals/cough-and-cold-medicines-active-ingredients/dextromethorphan-hydrobromide">dextromethorphan</a>. These medicines are used to relieve symptoms from a dry cough by acting on the “cough centre” in the brain. </p>
<p>Cough suppressants can sometimes cause drowsiness and are best avoided when coughing up mucous (a “wet” cough).</p>
<h2>Which cold and flu product is best for me?</h2>
<p>Think about your main symptoms when selecting a product and read the label carefully. </p>
<p>Avoiding medicines you don’t need will reduce the risk of side effects. A decongestant-only tablet or nasal spray, for instance, may be better than a combination product when your main symptom is a blocked nose. </p>
<p>It’s best not to use more than one cold and flu product at the same time without checking with your doctor or pharmacist.</p>
<p>Cold and flu products may not be suitable for some people. Always ask your pharmacist for advice if you have pre-existing medical conditions, or you are pregnant or breastfeeding. </p>
<p>Cold and flu medicines are <a href="http://www.tga.gov.au/behind-news/cough-and-cold-medicines-children-changes">not suitable</a> for children under six years of age and should only be given to children aged six to 11 years after discussion with a doctor or pharmacist.</p>
<h2>The fine print</h2>
<p>Cold and flu products are intended for short-term use only. <a href="https://www.nps.org.au/__data/assets/pdf_file/0004/211567/NPS-Cold-and-Flu-Brochure-May-2014.pdf">See your doctor</a> if your symptoms get worse.</p>
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<p><em>If you have specific questions about cold and flu tablets, ask your pharmacist for further advice, check the <a href="http://www.nps.org.au/topics/how-to-be-medicinewise/finding-information-on-medicines/what-is-consumer-medicine-information">consumer medicines information</a> (CMI) for the specific product, or call <a href="http://www.nps.org.au/contact-us/medicines-line">Medicines Line</a> on 1300 633 424.</em></p><img src="https://counter.theconversation.com/content/36481/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Janet Sluggett has received funding from the Australian Commission on Safety and Quality in Health Care, and works on a national quality improvement program funded by the Australian Government Department of Veterans' Affairs. Janet is a member of a national working group that makes recommendations about the advisory labels affixed to medicines when they are dispensed.</span></em></p>Pharmacies have aisles full of cold and flu tablets. But which product is the best one for you? And will it really help you feel better?Janet Sluggett, Research Fellow: Quality Use of Medicines and Pharmacy Research Centre, Sansom Institute for Health Research, University of South AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/181002013-10-01T20:36:41Z2013-10-01T20:36:41ZPollen counting is not something to be sneezed at<figure><img src="https://images.theconversation.com/files/32248/original/hfm8t67s-1380607866.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Hay fever affects one in six Australians.</span> <span class="attribution"><span class="source">Ed Newbigin</span></span></figcaption></figure><p>Ah, spring, the sun shines again, the birds sing and - ach-hoo! Airborne grass pollens trigger bouts of hay fever and episodes of asthma in people with pollen allergies.</p>
<p>But there is a way we could mitigate the impact of the season - pollen counts. These work in the same way as summer <a href="http://www.bom.gov.au/uv/">UV alerts</a>, by telling us when there’s enough of something around to cause health harms. </p>
<p>And this helps manage the impact of UV or pollen by giving us time to prepare, by wearing UV protection, for instance, or taking antihistamines. But while this sounds like a good idea, most places in Australia don’t have a pollen count, so those of us with allergies are left to our own devices.</p>
<h2>Pollen and health</h2>
<p>Let’s talk first about how pollen affects health. Hay fever is the most obvious example. </p>
<p>According to the <a href="http://www.abs.gov.au/AUSSTATS/abs@.nsf/0/9B34B8C8BF2FDA34CA25773700169C83?opendocument">2007–08 National Health Survey</a>, hay fever affects one in six Australians, severely impairing their quality of life by making sleep difficult and causing them to under-perform at work or school. </p>
<p>Hay fever is strongly associated with asthma; more than 80% of allergic asthmatics also have hay fever. Asthma costs the Australian community over $700 million annually and this impact has made it one of the country’s <a href="http://www.aihw.gov.au/national-health-priority-areas">national health priorities</a>.</p>
<p>Asthma and hay fever are caused by our immune systems responding inappropriately to substances in the environment that are not harmful. These are known as triggers. </p>
<p>Hay fever triggers cause the lining of the eyes, nose and throat to become inflamed, producing the typical symptoms of sneezing, itchy eyes and a runny nose. Asthma triggers cause the lining of the small airways of the lung to swell, making it harder to breath.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/32251/original/5dh7kv3n-1380609655.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/32251/original/5dh7kv3n-1380609655.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/32251/original/5dh7kv3n-1380609655.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/32251/original/5dh7kv3n-1380609655.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/32251/original/5dh7kv3n-1380609655.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/32251/original/5dh7kv3n-1380609655.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/32251/original/5dh7kv3n-1380609655.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Asthma triggers cause the lining of the small airways of the lung to swell, making it harder to breath.</span>
<span class="attribution"><span class="source">Rod Begbie</span></span>
</figcaption>
</figure>
<h2>Free like the wind</h2>
<p>Pollen from certain wind-pollinated plants is the main asthma and hay fever trigger in the outdoor environment. The plants in question use wind to transport their pollen between plants, rather than relying on insects and birds. </p>
<p>Because they don’t need to attract animals, the flowers of wind-pollinated plants are rather dull in comparison to the bright, showy flowers of animal-pollinated plants. </p>
<p>But what they lack in colour, wind-pollinated plants more than make up for with prodigious pollen production. A single plant can release untold millions of pollen grains into the air. </p>
<p>While Australia’s native plants are generally not wind-pollinated, many introduced plants are. These include trees from the northern hemisphere commonly found in gardens and along suburban roads, such as birch, elm, and ash. </p>
<p>But the worst plants by far for pollen allergies are grasses. Perennial ryegrass is a valuable pasture grass planted across vast areas of southern Australia. By sheer weight of numbers perennial ryegrass pollen is Australia’s number one outdoor allergy trigger.</p>
<p>Flowering of perennial ryegrass across much of southern Australia peaks in November. And it’s no coincidence this is also the peak time for sales of the oral antihistamines.</p>
<h2>Knowledge network</h2>
<p><a href="http://www.bbc.co.uk/news/health-17944765">Pollen counting</a> can tell us how much grass pollen is in the air on a particular day. By combining this information with the weather forecast, we can predict grass pollen levels for the next few days. </p>
<p>Knowing the grass pollen forecast can help people allergic to grass pollen plan ahead. But before you can forecast pollen levels for a particular place, you need to have a few seasons’ worth of counts under your belt so you know how weather patterns affect pollen levels locally. </p>
<p>Unfortunately, Australia has very few pollen counting stations and most operate only sporadically. The lonely exception is <a href="http://www.melbournepollen.com.au/">Melbourne’s pollen count</a>, which has been running consistently for over 20 years.</p>
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<img alt="" src="https://images.theconversation.com/files/32246/original/6dyr3r6q-1380607778.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/32246/original/6dyr3r6q-1380607778.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/32246/original/6dyr3r6q-1380607778.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/32246/original/6dyr3r6q-1380607778.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/32246/original/6dyr3r6q-1380607778.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/32246/original/6dyr3r6q-1380607778.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/32246/original/6dyr3r6q-1380607778.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Perennial ryegrass pollen is Australia’s number one outdoor allergy trigger.</span>
<span class="attribution"><span class="source">Arthur Chapman</span></span>
</figcaption>
</figure>
<p>This makes a stark contrast with <a href="http://www.polleninfo.org/en/laenderauswahl.html">Europe</a>, where a network of more than 600 pollen counting stations operates throughout the northern allergy season. That’s from early spring, when the trees flower, through to early autumn when weeds, such as dock and mugwort, flower. </p>
<p>The network operates efficiently across several countries and languages. And a similarly large network of stations operates across <a href="http://www.aaaai.org/global/nab-pollen-counts.aspx">North America</a>.</p>
<p>Australia’s lack of a pollen count network is surprising and means we often guess at things we really should know. For instance, we suspect Australia’s allergy season will be relatively simple to track compared to Europe’s, as we mainly have to contend with grass pollen. </p>
<p>But subtropical grasses that flower in summer are abundant in northern parts of Australia adding to the burden of hay fever. Right now, we don’t have a way of quantifying their role in the hay fever and asthma experienced by the population.</p>
<h2>Knowledge and the power to help</h2>
<p>Melbourne’s pollen data has been vital for understanding how grass pollen in the air influences <a href="http://www.ncbi.nlm.nih.gov/pubmed/22515396">hospital admissions</a> for asthma. It seems ridiculous that we don’t know this for all Australian cities.</p>
<p>Not only do we need a network to monitor pollen, we need to be able to link it with weather forecasts for it to become a predictive tool.</p>
<p>On November 25, 2010, Melbourne’s ambulance service was overwhelmed with a massive number of calls from people with acute respiratory problems because of thunderstorm asthma.</p>
<p><a href="http://theconversation.com/explainer-what-is-thunderstorm-asthma-4159">Thunderstorm asthma</a> occurs when there’s a thunderstorm during a high pollen count period. Prediction of pollen-induced epidemics of thunderstorm asthma could help hospital emergency departments prepare for such events. </p>
<p>This is only one of the many ways a national pollen count network could help improve public health throughout Australia. We just need to join the rest of the developed world and start gathering data that can inform us about what to do.</p><img src="https://counter.theconversation.com/content/18100/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ed Newbigin has received funding for pollen counting from the NHMRC.</span></em></p><p class="fine-print"><em><span>Janet Davies is funded by an Australian National Health and Medical Research Council Development grant. She is the Principal Investigator of an Australian Centre for Ecological Analysis and Synthesis Working Group on Australasian Aerobiology, which is co-sponsored by Merck Sharpe and Dohme.
Janet Davies is an inventor on two patent applications for improving diagnosis and treatment of subtropical grass pollen allergy. She has received consultancies and collaborative research funds from Stallergenes.</span></em></p>Ah, spring, the sun shines again, the birds sing and - ach-hoo! Airborne grass pollens trigger bouts of hay fever and episodes of asthma in people with pollen allergies. But there is a way we could mitigate…Ed Newbigin, Associate Professor of Botany, The University of MelbourneJanet Davies, Senior Research Fellow, Lung and Allergy Research Centre, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.