Symptoms of hay fever, and often asthma, are triggered by allergies. If you have an allergy, your immune system has an abnormal reaction to something that’s usually harmless, such as pollen or dust mites. This causes symptoms such as sneezing, a blocked nose, and itchy or watery eyes in hay fever, and difficulty breathing in asthma. Immunotherapy is a treatment that aims to lessen these symptoms by retraining the immune system. It involves regularly exposing the immune system to tiny amounts of the substance that is triggering an allergic reaction, which is called an allergen. The idea is that, over time, the immune system becomes more accustomed to the allergen, so it no longer reacts so strongly when it comes into contact with it. Immunotherapy often involves getting regular injections containing the allergen for several years. A newer treatment is to place tablets or drops containing the allergen under your tongue. This treatment, called sublingual immunotherapy, is easier to take and doesn’t require regular doctor’s appointments. However, it’s less clear how well it works. To learn more, researchers found 63 studies on sublingual immunotherapy that included 5,131 people in total, ranging in age from 4 to 74 years old. They looked at whether people’s symptoms improved more with immunotherapy than with other treatments, most often a dummy (placebo) treatment. They also looked closely at the quality of the studies and the overall strength of the evidence. What does the new study say? Overall, the studies suggested that sublingual immunotherapy can lessen the symptoms of hay fever and asthma. The findings were strongest for asthma, where researchers found high-quality evidence that immunotherapy helped. Out of 13 studies, all found that people’s symptoms improved with sublingual immunotherapy. In eight of the 13 studies, people’s symptoms improved by more than 40 percent on average - the amount the researchers looked for as a sign the treatment had a strong effect on people’s symptoms. Dust mites were the most frequently studied allergen for asthma. For hay fever, the researchers found medium-strength evidence that sneezing and other symptoms affecting the nose (rhinitis) improved with sublingual immunotherapy. All 36 studies reviewed found some improvement, with nine finding that people’s symptoms improved more than 40 percent on average. For itchy, watery eyes caused by hay fever, the researchers also found medium-strength evidence in favour of immunotherapy, with 12 out of 13 studies finding an improvement in symptoms, and three finding more than a 40 percent improvement on average. The most frequently studied allergens for hay fever were grasses and dust mites. The findings were similar when researchers looked separately at children alone. People frequently said they felt some irritation in their mouth where they applied the immunotherapy. However, there were no reports of serious, life-threatening reactions
Posted on: Sun, 29 Sep 2013 08:18:38 +0000
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