Treatment of chronic idiopathic urticaria with combined H1 and H2 blockers.

Combined H1 (cyproheptadine) and H2 antihistamines (cimetidine) were tried in eight patients with chronic urticaria who were previously unresponsive to conventional anti-urticarial regimens, including type I antihistamines, hydroxyzine, ephedrine and corticosteroids. 50% of the patients responded with 90% or greater improvement within 10 days. The remaining 50% showed no benefit. Side effects of the medications were minimal. These results indicate that a 10 day trial of both H1 and H2 antihistamines may be useful in patients with chronic urticaria resistant to all other standard treatment modalities.