Patch test reactions to human dander in atopic dermatitis.

Patch tests reactions to human dander were positive in 120 of 181 (66%) patients with atopic dermatitis, in two of 28 (7%) patients with allergic contact dermatitis, and in one of 31 (3%) normal controls. The frequency of positive reactions was significantly higher in patients with atopic dermatitis. The reactions consisted of erythema and papules, which histologically showed an eczematous change at the upper parts of hair follicles. There was significant correlation between patch test reactions to human dander and delayed intradermal reactions to the same substance in atopic patients. It is suggested that certain patients with atopic dermatitis exhibit contact hypersensitivity to human dander. Whether or not the hypersensitivity has any relationship to the pathogenesis of the dermatitis was not determined in this study.