• Vascular reactivity to intracutaneously injected histamine phosphate was examined in both the normal and affected skin of 50 patients with atopic dermatitis and 30 patients with allergic contact dermatitis. Reduced histamine reactions occurred consistently in the slightly lichenified skin of patients with atopic dermatitis and in skin sites of allergic contact dermatitis. The normal skin of patients with atopic dermatitis usually showed normal erythematous reactions to intracutaneously injected histamine. It seems likely that the reduced histamine reaction seen in the lesions of atopic dermatitis is a secondary phenomenon.
(Arch Dermatol 1982;118:244-245)