In drug-induced lupus not all the typical features of systemic lupus erythematosus are seen, with renal and nervous system involvement being unusual. It usually resolves on stopping the drug.

Most common causes

• procainamide
• hydralazine

Less common causes

• isoniazid
• minocycline
• phenytoin

PC

• arthralgia
• myalgia
• skin (e.g. malar rash) and pulmonary involvement (e.g. pleurisy) are common

Investigations

• ANA positive in 100%, dsDNA negative
• anti-histone antibodies are found in 80-90%
• anti-Ro, anti-Smith positive in around 5%