Primary acquired cold urticaria. Double-blind comparative study of treatment with cyproheptadine, chlorpheniramine, and placebo.

Eight subjects with primary-acquired cold urticaria were treated with chlorpheniramine maleate, cyproheptadine hydrochloride, and placebo in a double-blind clinical trial. During three separate seven-day treatment periods, each patient took 4 mg of either active drug or lactose placebo three times a day. Objective measurements were made at the beginning and end of each treatment period by establishing the minimum time (MT) of cold stimulus application required to provoke urtication. In addition, the spontaneous appearance of cold urticaria lesions was recorded during each treatment period. The MT required for induction of urtication with a cold stimulus was significantly greater for eight patients receiving cyproheptadine as compared to chlorpheniramine or placebo (P less than .01). The study demonstrated that cyproheptadine had a significant suppressive action on experimental cold-induced urticaria, while placebo and chlorpheniramine proved ineffective.