Hydralazine-induced vasculitis is an established autoimmune entity but widely underdiagnosed despite its initial description in 1953. Hydralazine-induced lupus occurs in 5% to 10% of patients and is characterized by fever, arthralgias, rash, anemia, leukopenia, and positive antinuclear antibodies. Renal involvement is rare in drug-induced systemic lupus erythematosus but can occur. Hydralazine may also be associated with an antineutrophil cytoplasmic antibody to complicate the diagnostic evaluation. There are no definitive diagnostic criteria for hydralazine-induced lupus, and diagnosis relies on chronic exposure to high doses of hydralazine with positive antinuclear and antihistone antibodies and classical histopathological findings. We describe a 48-year-old man with fatigue, anemia, and renal failure from hydralazine-mediated lupus with concomitant antineutrophil cytoplasmic antibodies and highlight the importance of medication history and scrupulous interpretation of serologies and biopsy for diagnosis and management of this familiar yet underrecognized disease. Clinicians should analyze the risk of hydralazine-induced adverse effects before initiating therapy and continue clinical vigilance while patients are on hydralazine.
Keywords: ANCA vasculitis; anemia; hydralazine; lupus nephritis; renal failure.