Mucocutaneous ulcerations secondary to methotrexate.

Although methotrexate (MTX) is used in several medical specialties including dermatology, rheumatology, and oncology, drug-induced mucocutaneous ulcerations rarely are reported. We present a 36-year-old woman with plaque psoriasis and psoriatic arthritis being treated with oral MTX (12.5 mg weekly) and oral methoxsalen plus UVA. Following an increase in MTX dose, she developed erosions and ulcerations on her oral mucosa and within her psoriatic plaques. All erosions and ulcerations healed within 2 weeks upon discontinuation of MTX.