Chronic urticaria is defined by urticarial lesions persisting at 6 weeks. The cause is not found in about 75% of cases (chronic idiopathic urticaria). The gold standard treatment consists of anti-H1 molecules. In severe cases, refractory to anti-H1, few therapeutic alternatives exist. Methotrexate, which is not expensive and often prescribed by dermatologists, has been efficiently tried in an open study on severe chronic idiopathic urticaria, and also in few case reports.

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.

Inclusion Criteria:

Patients who met the diagnostic criteria for chronic idiopathic urticaria, previously treated by

• 3 different molecules of anti-H1 or
• a combination of 2 different molecules of anti-H1 or
• 1 molecule of anti-H1 with at least a double dose for a total treatment duration of ≥ 3 months before inclusion
• With persistency of at least 7 days with urticarial lesions in the previous month

Exclusion Criteria:

• Differential diagnosis of chronic idiopathic urticaria (urticarial vasculitis)

• Treatment with montelukast or immunosuppressive drugs during the previous month

• Contraindications to methotrexate

  • Allergy to methotrexate
  • Treatment which are contraindicated with methotrexate
  • Pregnancy, possibility of getting pregnant (no effective contraception), breastfeeding
  • Anomalies in liver function (transaminases or liver failure at a rate 1.5 X normal)
  • Severe renal impairment (creatinine clearance calculated by the cockcroft formula <50 ml / min)
  • Chronic respiratory failure
  • Active infectious chronic diseases (viral hepatitis, HIV)
  • History of neoplasia
  • Mental deficiency
  • Involvement in another drug clinical trial