Severe atopic dermatitis and leflunomide: first clinical experience and highlights of pertinent experimental data.

Atopic dermatitis is a common chronically relapsing disease affecting about 10 percent of children and 3 percent of adults. Currently, no standard management exists for long-term treatment. Topical corticosteroids and recently calcineurin-inhibitors are effective in most patients. In severe cases, however, systemic agents have to be employed. Their use may be limited by unwanted effects or insufficient long-term efficiency. Leflunomide is an immunomodulating and disease-modifying antirheumatic drug with anti-inflammatory and immunosuppressive activity, exhibiting an extremely long in vivo half life. Because T cells and eosinophils play an important role in the pathophysiology of atopic dermatitis, and long-term treatment is often required, leflunomide seems to be ideally suited for treatment of severe atopic eczema. We present a case highlighting the application regimen of leflunomide, and discuss the pathophysiological mechanism of action in atopic dermatitis. Because treatment benefit differs between patients, we propose the design of a proof-of-principle study for leflunomide in atopic dermatitis encompassing an evaluation of predictive markers for successful application.