Del Pozo J, Martínez W, García-Silva J, Almagro M, Peña-Penabad C, Fonseca E
Department of Dermatology, Hospital Juan Canalejo, Xulbias de Arriba 84, 15006 La Coruña, Spain.
Eur J Dermatol. 2001 Sep-Oct;11(5):450-2.
Methotrexate (MTX) inhibits DNA synthesis by competition with dihydrofolate reductase. Adverse cutaneous reactions to MTX are usually dose-related and have been mainly reported in patients receiving extremely large doses of chemotherapy. Painful erosion of psoriatic plaques has been often reported as an early sign of MTX toxicity, but cutaneous ulceration as a sign of MTX toxicity in patients without psoriasis has only been described in one case. We report a patient with rheumatoid arthritis and without psoriasis who developed cutaneous ulceration on the knuckles as a sign of MTX toxicity. Cutaneous ulceration by MTX toxicity is an exclusion diagnosis and its pathogenic mechanism may be multifactorial, including direct toxicity of the drug in addition to local factors.
甲氨蝶呤（MTX）通过与二氢叶酸还原酶竞争来抑制DNA合成。MTX的皮肤不良反应通常与剂量相关，主要报道于接受超大剂量化疗的患者中。银屑病斑块的疼痛性糜烂常被报道为MTX毒性的早期迹象，但在无银屑病患者中，皮肤溃疡作为MTX毒性的迹象仅在1例中被描述过。我们报告1例类风湿关节炎且无银屑病的患者，其指关节出现皮肤溃疡，作为MTX毒性的迹象。MTX毒性导致的皮肤溃疡是一种排除性诊断，其致病机制可能是多因素的，包括药物的直接毒性以及局部因素。
