Antihistone antibodies (AHAs) are classically associated with drug-induced lupus erythematosus.1 However, multiple studies have revealed that AHAs are present with significant frequency in several other autoimmune diseases, including systemic lupus erythematosus unrelated to medications, rheumatoid arthritis, juvenile rheumatoid arthritis, primary biliary cirrhosis, autoimmune hepatitis, dermatomyositis/polymyositis, and scleroderma.2,3