Almost 8% of adults and 9% of children in the U.S. suffer from nasal allergies or hay fever, and the symptoms result in over 11 million visits to the doctor annually. Three million people in the U.S. further report an allergy to peanuts, or tree nuts or both, including 8% of children, according to the American Academy of Allergy Asthma and Immunology.
The prevalence of allergies also appears to have increased over the last 50 years and shows no signs of slowing down. As the House Call Doctor explained, allergy symptoms occur when our immune system mistakes a normal substance, like pollen or a nut, for an intruder, and wages war against it through the release of antibodies. But why does this response happen in some people and not others? Why are allergies becoming more and more common? If you were lucky enough to be an allergy-free kid, could you still develop allergies as an adult?
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Genetics and Our Environment
Scientists are not entirely sure why some people suffer from allergies while others live allergy-free, but studies show that genetics and environment are both important factors.
Studies of twins for which at least one twin is allergic to peanuts have found that, in the case of fraternal twins, the other twin has a 7% chance of also having the allergy. Among identical twins, however, both twins were allergic in 64% of cases. Thus, our genetics clearly influence whether or not we will have an allergy.