Introduction: Leflunomide is an immunomodulating agent with proven efficacy in rheumatoid arthritis. Although its overall safety profile is good, a few cases of toxic epidermal necrolysis have been reported.
Case report: This 36-year-old woman had rheumatoid arthritis that proved refractory to sulfasalazine and methotrexate, which were used successively in combination with symptomatic drugs. Leflunomide was started. A maculopapular rash and a fever developed 2 weeks later. The skin lesions spread rapidly to most of the body, and ulcers of the ocular and oral mucosa appeared. Leflunomide was stopped. Cholestyramine washout and prednisolone (60 mg/day) were given. The skin lesions healed over the next month. Punctate keratitis with keratinization of the cornea led to complete loss of vision.
Discussion: The main adverse effects of leflunomide consist of diarrhea, nausea, liver enzyme elevation, hypertension, alopecia, and allergic skin reactions. A few cases of severe skin reactions such as toxic epidermal necrolysis have been reported. They require immediate discontinuation of the drug and a washout procedure to hasten drug elimination from the body.
Conclusion: Close monitoring for severe skin reactions is in order when using leflunomide.