Cutaneous histamine levels and histamine releasability from the skin in atopic dermatitis and hyper-IgE-syndrome.

We determined the histamine content in the skin of 22 adults with atopic dermatitis, one patient with hyper-IgE-syndrome, and 20 controls by the enzymatic double isotope assay. In addition, we performed a pilot study of histamine degradation in the skin. We tested, furthermore, the releasability of histamine from skin sections of patients with atopic dermatitis and healthy controls upon challenge with acetylcholine, anti-IgE, and compound 48/80. Histamine was also determined in 13 plasma specimens and was always less than 1 ng/ml. The mean +/- SEM histamine concentration in the skin was 196 +/- 30 ng/mg protein in controls and 262 +/- 68 ng/mg protein in atopic dermatitis (no statistically significant difference). One control and three patients with atopic dermatitis exhibited a slight, the hyper-IgE patient a marked, elevation of the skin histamine content. No gross differences in the degradation rate of histamine were observed between patients and controls. Acetylcholine and 48/80 induced the same histamine release in both groups; with anti-IgE, almost the double amount of histamine was released from the skin of atopic dermatitis patients as compared to controls. These findings suggest an enhanced releasability of histamine upon immunologic challenge in atopic dermatitis.