Association of Asthma with Serum IgE Levels and Skin-Test Reactivity to Allergens

We investigated the association of self-reported asthma or allergic rhinitis with serum IgE levels and skin-test reactivity to allergens in 2657 subjects in a general-population study. Regardless of the subjects' status with respect to atopy or their age group, the prevalence of asthma was closely related to the serum IgE level standardized for age and sex (P<0.0001), and no asthma was present in the 177 subjects with the lowest IgE levels for their age and sex (>1.46 SD below the mean). The log odds ratio increased linearly with the serum IgE level after we controlled for possible confounders and the degree of reactivity to skin tests. In contrast, allergic rhinitis appeared to be associated primarily with skin-test reactions to common aeroallergens, independently of the serum IgE level. We conclude that asthma is almost always associated with some type of IgE-related reaction and therefore has an allergic basis, although not all the allergic stimuli that cause asthma appear to have been included in the battery of common aeroallergens we used to assess atopic status. These findings challenge the concept that there are basic differences between so-called allergic (“extrinsic”) and nonallergic (“intrinsic”) forms of asthma. (N Engl J Med 1989; 320:271-7.) IT is generally accepted that there are both allergic and nonallergic forms of asthma, and the distinction is usually based on the presence or absence of allergy skin-test reactivity to one or more aeroallergens considered capable of inducing the disease. Since Rackemann introduced the terms in 1918,¹ asthma that can be shown to be related to hypersensitivity to a foreign substance has been described as “extrinsic” otherwise, the disease has been classified as “intrinsic.” After Ishizaka² and Johansson³ and their colleagues identified immunoglobulin E (IgE) as the antibody responsible for the immediate type of immune response, a number of authors.