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Keratinocyte dystrophy identifies skin toxicity with low-dose methotrexate

Keratinocyte dystrophy may help diagnose skin toxicity in patients taking low-dose methotrexate, even in patients with no known risk factors or administration errors, according to recent study results.

“Mucosal and skin erosions with keratinocyte dystrophy seem characteristic of methotrexate-induced mucocutaneous toxicity,” Julie Delyon, MD, and colleagues wrote. “Such lesions, preceding or accompanied with mild decreases in blood cell counts, should be viewed as warning signs of potentially life-threatening methotrexate toxicity, even in patients without known risk factors or methotrexate administration errors.”

Delyon and colleagues evaluated five patients with skin toxicity caused by low-dose methotrexate therapy. Patients had mucosal ulcers or cutaneous erosions, and researchers performed biopsies on the patients to determine the histopathology of the skin surrounding the erosion or ulcer.

They found that all five patients had acute mucosal ulcers, four patients had moderately abnormal blood counts and three patients had skin erosions. Biopsied specimens showed keratinocyte dystrophy in all five cases. The researchers identified a methotrexate dosage or administrative error for three patients. – by Jeff Craven

Disclosure: The researchers report no relevant financial disclosures.