LEUKOCYTOCLASTIC VASCULITIS INDUCED BY LOW-DOSE METHOTREXATE - IN-VITRO EVIDENCE FOR AN IMMUNOLOGICAL MECHANISM

The rare occurrence of methotrexate (MTX)-induced vasculitis has been associated mainly with high or intermediate MTX doses. We report herei n a case of cutaneous leukocytoclastic vasculitis (LCV) following trea tment with low-dose oral MTX (7.5 mg/week) for rheumatoid arthritis, T he histological findings of a cutaneous lesion were consistent with dr ug-induced vasculitis. The clinical and histological findings, includi ng the temporal relationship between MTX intake and the onset of vascu litis, and the results of withdrawal and rechallenge tests, suggest a causal relationship, and indicate a drug-induced LCV due to MTX, The r ole of MTX in the induction of the vasculitis was further supported by a positive mast cell degranulation (MCD) test. (C) 1998 Elsevier Scie nce B.V.