[Acute methotrexate toxicity in psoriasis].

A 71-year-old man with psoriasis developed acute methotrexate toxicity after taking 10 mg daily on his own. A few days after, he showed painful erosions of psoriatic plaques and stomatitis. In addition to those mucocutaneous lesions, the clinical background includes bone marrow and intestinal involvement. The present clinical case underlies the relevance in selecting psoriasis patients regarding methotrexate treatment, following the particular guidelines.