Drug-induced lupus erythematosus

Definition

Drug-induced lupus erythematosus is an inflammatory autoimmune disorder that may affect many organ systems. It is caused from an adverse reaction to a medication.

Causes, incidence, and risk factors

Several medications are known to cause a syndrome that resembles systemic lupus erythematosus (SLE) - a chronic inflammatory autoimmune disorder that may affect many organ systems.

Drug-induced lupus erythematosus occurs as a result of a hypersensitivity reaction to a medication. The drug may react with cell materials, causing the body to react to itself and form antinuclear antibodies.

Drugs that are known to cause this type of reaction in some people include: procainamide, isoniazid, chlorpromazine, penicillamine, sulfasalazine, hydralazine, methyldopa, and quinidine. Symptoms tend to occur after taking the drug for a reasonable period of time, usually at least 3 to 6 months.

In drug-induced lupus erythematosus, the features of arthritis, systemic symptoms, and cardiac and pulmonary (lung) symptoms may be present. Other symptoms associated with SLE, such as lupus nephritis and neurological disease, are rare.

Drug-induced lupus erythematosus also differs from SLE in that the course of the disease is usually not as severe as SLE. Usually, the symptoms resolve within a few days to weeks after stopping the medication. The sex distribution of drug-induced lupus erythematosus is equal, whereas in SLE, women are affected more often than men.

Symptoms

• Fever
  
• Loss of appetite
  
• General discomfort, uneasiness, or ill feeling (malaise)
  
• Weight loss
  
• Skin rash
  o Malar "butterfly" rash
  o Skin rash aggravated by sunlight
  
• Joint pain
  
• Joint swelling
  
• Blurring vision
  
• Pleuritic chest pain
  

Signs and tests
The history shows use of a medication associated with drug-induced lupus. An examination of the skin shows characteristic skin rash or lesions. Signs of pericarditis may be present. Listening to the chest with a stethoscope (auscultation) may reveal abnormal sounds such as heart murmur, pleural friction rub, or pericardial friction rub.

Tests for SLE include:

• Antinuclear antibody (ANA) panel
  
• Lupus erythematosus cell test (rarely performed nowadays)