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.
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.
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.
Close monitoring for severe skin reactions is in order when using leflunomide.