Heterogeneity of serum IgE levels in atopic dermatitis.

To determine whether serum IgE levels in patients with atopic dermatitis (AD) have a relationship to familial background of atopic respiratory disease (ARD), serum IgE levels were measured in 50 AD patients who had personal history of ARD, 37 AD patients who did not have personal history of ARD but had family history of ARD, and 52 "pure" AD patients who had neither personal nor family history of ARD. The "pure" AD patients showed significantly lower serum IgE levels than AD patients who had personal or family history of ARD. It is suggested that AD patients may be classified into at least two subgroups: those with ARD predisposition who have an enhanced IgE producing potential, and those without ARD predisposition who have a low or not-enhanced ability for IgE production.