A Case of Cutaneous Side Effect of Methotrexate Mimicking Behçet's Disease

Abstract

Methotrexate (MTX) is an antimetabolite which interferes with DNA synthesis, and it is used for the treatment of moderate to severe psoriasis, atopic dermatitis and a wide variety of cutaneous diseases. Although many adverse effects of MTX, including cutaneous ulcerations, have been documented, multifocal mucosal ulceration mimicking Behçet's disease has not been reported. In our case, a 63-year-old female presented with oral, vaginal ulcer and multiple purpuric patches on both legs. Considering patient's clinical course and histopathologic findings, we presumed that these reactions may be the side effect of MTX administered for treatment of necrotizing scleritis. Herein we report the cutaneous side effect of MTX that manifested clinically like Behçet's disease.

Keywords: Adverse reaction; Behçet's disease; Methotrexate.

Fig. 1

Multiple erythematous erosions in the oral cavity.

Fig. 2

Erythematous ulcers on the lower extremities.

Fig. 3

(A) Multiple erosive erythematous to purpuric crusted patches and papules on both legs. (B) Flattening of rete ridges, dyskeratotic keratinocytes in the epidermis, and vacuolar degeneration and hyperpigmentation of basal cell layer. In the dermis, mild vascular proliferation and perivascular infiltration of lymphocytes were demonstrated. No evidence of vasculitis was seen (A: H&E ×100).