Diagnosis of inhalant allergies: patient history and testing.

In the United States, roughly 20% to 25% of the general adult population is afflicted by some form of chronic allergic respiratory disease, making allergy one of the most commonly diagnosed disorders. Among children, allergic disease is more common, with some sources estimating that it affects up to 40% of children. The focus of this article involves making the diagnosis of the most familiar and best understood of the hypersensitivity reactions, type 1 hypersensitivity, also termed immediate hypersensitivity. Although type 1 hypersensitivity can be caused by ingestion of food antigens or pharmaceuticals, this article focuses on IgE-mediated allergic disease caused primarily by inhalant allergens.