Involvement of sensory nerve endings in cold and heat urticaria.

The involvement of sensory nerve endings in acquired cold and heat urticaria was studied in 8 patients. After repeated topical application of capsaicin, the skin was tested for whealing with cold and heat stimuli. Capsaicin pretreatment prevented the urticarial responses for 4-7 days. Since capsaicin is known to induce selective impairment of the chemosensitive nerve endings, the results suggest that these nerve fibers may play an important role in acquired cold and heat urticaria. The possible mechanisms are discussed.