Methimazole-induced lupus erythematosus: a case report.

A 15-year-old girl had a history of diffuse goiter and received methimazole treatment 2 months before admission to the hospital. She developed bilateral lower leg edema 5 days before admission and the laboratory examinations revealed leukopenia, anemia, proteinuria, and granular cast. Positive antinuclear antibodies and anti-double strand (anti-ds) DNA antibodies were noted, although complement levels were not reduced. Myeloperoxidase antineutrophil cytoplasmic antibody was positive. A renal biopsy disclosed that there was focal segmental glomerulosclerosis. Methimazole was discontinued, and she was treated with prednisolone and Plaquenil, after which the symptoms and laboratory tests became normal within 40 days. The prednisolone was discontinued after treatment for seven months. Currently, the anti-dsDNA, C3, C4, CBC, urinalysis, and thyroid function tests are within normal limits. With hydroxychloroquine and levothyroxine, she was free of symptoms after discontinuation of methimazole until now (about 21 months).