Methotrexate for the treatment of adult atopic dermatitis.

Atopic dermatitis (AD) is a chronic inflammatory skin disease mediated by allergen-specific T cells which are recruited and activated in lesional skin. Methotrexate (MTX) is an old systemic agent used at low dosage for the treatment of psoriasis, another T cell-mediated skin disorder. Since MTX has been shown to improve the clinical symptoms of eczema in a model of antigen-specific dermatitis in mice, we postulated that it could be an effective treatment of AD. In the present open retrospective study, we report our results on the treatment of moderate to severe AD by MTX. Twenty patients (17 to 68-years-old) with low responses to routine therapies were treated (three months to 2 1/2 years) with a weekly dose of MTX ranging from 7.5 to 25 mg. The evaluation was made on physician's global assessment after 3 months of MTX use, and showed that 75% (15/20) of patients improved after 3 months of MTX use, among which 13/20 with an improvement>70%. The beginning of improvement was observed between the fourth and the eighth week after MTX was initiated. Tolerance was good. However, nausea and increase of liver enzymes were observed in 5 patients and required discontinuation of MTX in 2 patients. In conclusion, MTX seems to be an effective and safe treatment of AD. Placebo-controlled clinical trials are needed to confirm our observations and to define more precisely the effectiveness and safety of MTX in adult AD.