Drug-induced lupus

Drug-induced lupus erythematosus (DILE) is a form of lupus, an autoimmune disease, which is triggered by certain prescription medications. It is characterized by symptoms similar to those of systemic lupus erythematosus (SLE), including rash, arthralgia, and serositis. However, unlike SLE, the symptoms of DILE typically resolve after discontinuing the offending medication.

Etiology

DILE is caused by a reaction to certain medications. The most common drugs known to cause DILE are hydralazine, procainamide, and isoniazid. Other drugs that have been associated with DILE include quinidine, chlorpromazine, and methyldopa. The exact mechanism by which these drugs cause DILE is not fully understood, but it is believed to involve an interaction between the drug and the immune system that leads to an autoimmune response.

Clinical Presentation

The symptoms of DILE are similar to those of SLE, but are usually less severe. The most common symptoms include fever, fatigue, arthralgia, and myalgia. A rash is also common, particularly a malar rash that is characteristic of lupus. Other symptoms can include serositis, lymphadenopathy, and hepatosplenomegaly. Laboratory findings can include leukopenia, thrombocytopenia, and the presence of autoantibodies, particularly antihistone antibodies.

Diagnosis

The diagnosis of DILE is based on the presence of symptoms consistent with lupus, a history of exposure to a drug known to cause DILE, and the resolution of symptoms after discontinuation of the drug. Laboratory tests can also be helpful in the diagnosis, particularly the presence of antihistone antibodies, which are found in the majority of cases of DILE.

Treatment

The primary treatment for DILE is discontinuation of the offending drug. In most cases, this leads to a resolution of symptoms. In some cases, additional treatment may be needed to manage symptoms, such as nonsteroidal anti-inflammatory drugs (NSAIDs) for arthralgia and myalgia, and corticosteroids for more severe symptoms.

Prognosis

The prognosis for DILE is generally good, with most patients experiencing a complete resolution of symptoms after discontinuation of the offending drug. However, in some cases, symptoms may persist for a period of time after discontinuation of the drug, and in rare cases, DILE can progress to SLE.