Although allergies and asthma are separate conditions, they are related. People who have allergies — particularly those that affect the nose and eyes — are more likely to have asthma. If you have allergies or asthma, your child is more likely to have it, too, because the tendency to develop these conditions is often inherited.

But not everyone who has allergies has asthma, and not all cases of asthma are related to allergies. About 75% of kids who have asthma also have an allergy to something. And many people who have asthma find their symptoms get worse when they're exposed to specific allergens (things that can cause allergic reactions in some people).

With any kind of allergy, the immune system overreacts to normally harmless substances such as pollen or dust mites. As part of this overreaction, the body produces an antibody of the immunoglobulin E (IgE) type, which specifically recognizes and attaches to the allergen when the body is exposed to it.

When that happens, it sets a process in motion that results in the release of certain substances in the body. One of them is histamine, which causes allergic symptoms that can affect the eyes, nose, throat, skin, gastrointestinal tract, or lungs. When the airways in the lungs are affected, symptoms of asthma can occur.

Future exposure to the same allergens can cause the reaction to happen again. So if your child has asthma, it's wise to explore whether allergies may be triggering some of the symptoms. Talk with your doctor about how to identify possible triggers, which can be things other than allergens, such as cold air, pets, or tobacco smoke. Your doctor might also recommend visiting an allergist for allergy tests. If your child is allergic to something, that substance may be causing or contributing to asthma symptoms (coughing, wheezing, and trouble breathing).

If it does look like allergens are an important trigger for the asthma symptoms, do what you can to help your child avoid exposure to the allergens involved. If this doesn't control the asthma symptoms adequately, the doctor may also prescribe medications or allergy shots.

Reviewed by: Elana Pearl Ben-Joseph, MD
Date reviewed: June 2007