Leflunomide: dermatologic perspective.

Leflunomide, an isoxazole derivative, is a disease-modifying antirheumatic drug. It has successfully been used for the treatment of rheumatoid arthritis as a feasible alternative to methotrexate. Recently, leflunomide has been used in certain dermatologic conditions. Medline/PubMed search revealed only 201 articles of its application in dermatologic conditions, of which 21 were relevant for inclusion. Prime mode of action of leflunomide is through the inhibition of dihydroorotate dehydrogenase, a key enzyme in the de novo pyrimidine synthesis pathway used by lymphocytes for clonal expansion. The current level of evidence and strength of recommendation suggest its use in psoriasis and psoriatic arthritis. However, the use of leflunomide in severe atopic dermatitis, systemic lupus erythematosus, Wegener's granulomatosis, primary Sjögren's syndrome, bullous pemphigoid, dermatomyositis, sarcoidosis and systemic sclerosis still requires further evaluation.