Low-dose methotrexate-induced skin toxicity: Keratinocyte dystrophy as a histologic marker

Methotrexate-induced cutaneous ulceration in 3 nonpsoriatic patients: Report of a rare side effect

“…The histologic features of MTX-induced cutaneous toxicity are focal dermoepidermal separation with keratinocyte necrosis and dystrophy, specifically cytologic atypia and dysmaturation 2, 6. Biopsies of lesions from all 3 patients displayed keratinocyte dystrophy.…”

Low dose methotrexate induced asymptomatic keratinocyte dystrophy in a patient of psoriasis vulgaris

“…Methotrexate exerts its antiproliferative action by inhibiting the enzyme dihydrofolate reductase, needed for purine synthesis. 3 The common presentation of acute methotrexate toxicities are acute myelosuppression and gastrointestinal mucositis. Owing to their increase sensitivity to methotrexate, mucositis usually precedes the onset of myelosuppression.…”

“…4 Although mucocutaneous erosions associated with methotrexate toxicity commonly affects patients with increased methotrexate exposure because of dose errors, renal failure or drug interactions, but can also occur without any known risk factor. 3 Painful erosions of psoriatic plaque or rarely normal skin thought to be a marker of acute methotrexate toxicity. 4 The theory is being supported by the histopathological feature of KD, revealed from the edge of the mucocutaneous erosions.…”

Reply

“…Blood cell count abnormalities were found in 4 patients, suggesting MTXinduced bone marrow toxicity. We concluded that MTX may induce dysplasia in rapidly renewing tissue, leading to epithelial dysmaturation with keratinocyte dystrophy in the skin and mucosa (3) and to blood cell dysmaturation in the bone marrow (6).…”