OBSERVATIONS ON THE ANTIPRURITIC EFFECT OF GUANETHIDINE IN ATOPIC DERMATITIS.

Guanethidine, 0.75 to 1.25 mg. per kg. per day, was found to alleviate the pruritus of acute atopic dermatitis in 19 out of 20 patients. It was not effective in patients with other dermatoses. An apparent partial tolerance to this treatment developed in six out of 10 patients re-treated. It had little or no therapeutic effect in 10 patients with a variety of other pruritic dermatoses, suggesting that this drug has a specific antipruritic action in patients with atopic dermatitis. In a double-blind study, 11 of 12 patients with atopic dermatitis treated with guanethidine experienced relief of pruritus. Four out of 12 patients using a placebo had complete or partial relief. Guanethidine, 1% to 10%, used topically was therapeutically no more effective than placebo. In view of the reported side effects and the anesthetic hazard encountered with guanethidine, further long-term studies are indicated before this drug is adopted for clinical use in the treatment of atopic dermatitis. The findings support the hypothesis that atopic dermatitis may be a manifestation of a hereditary defect in cutaneous noradrenaline binding.