BERLIN — A drug known to be beneficial in the treatment of allergies has also proved effective and well-tolerated for the treatment of acquired cold urticaria in a randomized, double-blind, placebo-controlled crossover study.
Rupatadine is a dual antagonist of histamine and platelet-activating factor (PAF) that has shown promising results in a clinical trial.
“We hypothesize that antiplatelet-activating factor activity may contribute to the excellent clinical effect we saw in this trial,” Dr. Martin Metz said at the annual congress of the European Academy of Dermatology and Venereology.
Patients who have cold urticaria respond to exposure to cold temperatures with erythematous wheals, severe itching, and mucosal swelling. The symptoms typically last from 30 minutes to 3 hours. Each patient has an individual critical temperature threshold: that is, the highest temperature that elicits wheals.
Rupatadine (Rupafin) resets the critical temperature threshold markedly downward in patients with cold urticaria, said Dr. Metz, of Charité University Hospital, Berlin.
He reported on 21 patients with acquired cold urticaria at two medical centers who were randomized to 20 mg of rupatadine daily or placebo for 1 week in the Acquired Cold Urticaria and Rupatadine Efficacy (ACURE) study. After a 2-week washout period, they were crossed over to the other study arm.
Treatment response was objectively measured using TempTest, a programmable device Dr. Metz described as “an electronic ice cube” placed against the skin. The mean critical temperature threshold of participants at baseline and on placebo was 15° C, but while on rupatadine, it dropped to below 4°C the lowest temperatureemsed for safety reasons.
At baseline, 13 patients had moderate-to-severe pruritus. During the rupatadine phase of the study, three patients had moderate pruritis and none had severe. Patients on rupatadine also experienced a significant reduction of cutaneous burning sensation.
During the rupatadine phase of ACURE, four patients reported mild fatigue, one complained of somnolence, and one patient reported a moderate headache.
The cause of cold urticaria is unknown. Additional studies comparing the effectiveness of rupatadine and antihistamines lacking PAF-inhibiting action in patients with cold urticaria are needed, Dr. Metz noted.
ACURE was sponsored by Uriach Pharma, which markets rupatadine in Europe, South America, and Africa. The drug is not currently available in the United States. Dr. Metz is a consultant to the company.