Methotrexate toxicity presenting as cutaneous ulcerations on psoriatic plaques.

Methotrexate (MTX) is an effective but potentially toxic treatment for psoriasis. We describe a patient who administered 20 mg daily of MTX for 5 d and presented with ulcerated and necrotic lesions on the psoriatic plaques, mouth erosions and hair loss. However, his psoriatic plaques and ulcerations totally healed rapidly within two weeks and no recurrence has been observed for the 6 months of follow up.