Randomized Clinical Trial Evaluating the Efficacy of Methotrexate in Addition to Anti-H1 Versus Placebo and Anti-H1 in the Treatment of Severe Chronic Idiopathic Urticaria

Chronic urticaria, defined by its persistence beyond 6 weeks, is a common condition (0.1% to 3% of the general population), occurring at any age. The etiology is not found in nearly 75% of cases (chronic idiopathic urticaria). Chronic idiopathic urticaria may resolve over several months or years. The quality of life of patients is usually strongly spoiled. The gold standard treatment consist of anti-H1 molecules. In severe cases, which are refractory to anti-H1, few therapeutic alternatives exist. Two studies have shown a benefit when adding to anti-H1, montelukast, anti-leukotriene, or cyclosporine. Methotrexate, which is another immunosuppressive drug, cheap and commonly prescribed by dermatologists, has been efficient in severe chronic urticaria, in an open study and in few case reports.

Methotrexate, an anti-metabolite drug which inhibits dihydrofolate reductase, is indicated in hematologic malignancies and in autoimmune diseases. It may be given by oral or parenteral administration, once a week, and requires regular monitoring of renal and hepatic function, and blood count.