[Management of idiopathic urticaria with H1 + H2 antagonists. A crossover double blind long-term study].

A randomized crossover double-blind study in a selected group of patients with idiopathic urticaria (15 patients; 10 females, 5 males; 20-80 years old) has been performed in order to examine the clinical efficacy of H1 + H2-antagonists in this disease, as compared with the H1-antagonist alone and with placebo. Chlorpheniramine (4 X 4 mg/d) and cimetidine (4 X 400 mg/d) were administered, each of them over 4 weeks, after one week wash-out period. The number of wheals, the time of their persistance as well as the presence of itching were daily registered and then evaluated. The entire group showed no difference between antihistamines and placebo. Nevertheless, 4 patients have registered a definitely better response to the H1-antagonist, 4 other patients responded distinctly better to the combined H1 + H2-treatment and 5 patients showed no preference at all. In a long-term follow up period of 3 months the effect of chlorpheniramine became even better, whereas the response to the combined treatment remained unchanged. It seems that the clinical efficacy of H1 + H2-antagonists is rather moderate in idiopathic urticaria. Nevertheless, in individual cases non-responding to H1-antagonist the combined administration of H1 + H2-antagonists may be more beneficial for the patient.