Epidemiology of allergy.

Atopic disease represents a spectrum of disorders characterized by abnormal sensitivity mediated by IgE; approximately 20% of Americans suffer from some form of allergic disease. The sequelae of inhalant and food allergies may present in many organ systems. Manifestations of allergic disease in one site are often associated with symptoms from another site. It is important for clinicians to understand the epidemiology of atopic disease and its causes to facilitate implementation of effective treatment and prevention strategies. This review focuses on the epidemiology of inhalant allergies causing allergic rhinitis and asthma and on IgE-mediated food allergies.