We have investigated levels of total and specific IgE against inhalant allergens in the sweat of 15 patients with atopic dermatitis, 10 patients with allergic rhinitis and high levels of specific IgE in the serum, and five patients with psoriasis without atopy as controls, by means of various commercial methods such as fluorescence immunoassay, nephelometry, chemiluminescence assay, enzyme immunoassay and the radioallergosorbent test. Total IgE and specific IgE antibodies were detectable in the sweat of patients with atopic dermatitis as well as of patients with allergic rhinitis alone. These levels of total IgE in the sweat correlated with the severity of the skin disease (P < 0.05). By means of the Ciba Corning assay (P < 0.001), the fluorescence immunoassay (P < 0.05) and the nephelometry assay (P < 0.05), positive correlations were then established between the levels of total IgE in the serum and the sweat. Moreover, specific IgE antibodies to birch pollen and Dermatophagoides pteronyssinus were detectable in the sweat and correlated positively with these specific IgE levels in the serum (P < 0.05). Further, the specific IgE levels against these allergens in the sweat also correlated with the severity of dermatitis (P < 0.05). It is suggested that these specific IgE antibodies against certain inhalant allergens in the sweat of patients with atopic dermatitis may play a role in allergen trapping in the skin.