Respiratory allergy sufferers have a lot of company


November 08, 1994|By Dr. Genevieve Matanoski | Dr. Genevieve Matanoski,Medical Tribune News Service

If you suffer from respiratory allergies, you're in good company; the National Institute of Allergy and Infectious Diseases estimates that more than 15 percent of Americans have respiratory allergies, affecting the sinuses, nose, throat and lungs. Armed with new understanding of the causes of allergic symptoms, doctors are devising new medications that do more than treat symptoms -- they prevent them from occurring in the first place.

Dr. Lawrence Lichenstein, director of the Asthma and Allergy Center at the Johns Hopkins Health Institutions, and Dr. Peyton Eggleston, also of Hopkins, shared their expert knowledge in helping me compile some answers for allergy sufferers.

Q: What are allergies?

A: Allergic reactions are the result of the body's immune reaction against an allergen. Unlike bacteria or viruses, an allergen is a harmless invader. It does not itself cause infection or disease. Some people, however, mount a defense against a specific allergen as though it were a deadly virus or infection. These allergic reactions can be quite severe, even life-threatening, such as those against bee toxins. Fortunately, reactions this extreme are comparatively rare.

Two phases of immune reaction take place before allergic symptoms appear. The first phase is sensitization, when the body encounters the allergen for the first time. Special antibodies are produced, which bind to white blood cells. If the allergen enters the body a second time, a phase called provocation, these cells start an immune reaction by binding to the allergen. In the process, a host of irritating chemicals, called mediators, are released. These mediators cause allergy symptoms. One well-known mediator is histamine.

Q: How can I limit my exposure?

A: Once a specific allergen has been identified, the next step is to lessen or eliminate contact with the offending substance. The best strategy is to try to get rid of the allergen source while shielding yourself from the allergen. Try these measures before investigating an allergy medication.

Dr. Matanoski is a physician and epidemiologist at the Johns Hopkins School of Hygiene and Public Health. She is founding director of its Institute for Women's Health Research and Policy.

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