Drug-induced lupus erythematosus resembles systemic lupus erythematosus (SLE). It 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 (antibodies against structures in the body's own cells).

Several medications are known to cause drug-induced lupus, including: procainamide, isoniazid, chlorpromazine, penicillamine, sulfasalazine, hydralazine, methyldopa, and quinidine. Symptoms tend to occur after taking the drug for 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 is usually not as severe as SLE. Usually, the symptoms go away within a few days to weeks after stopping the medication. Drug-induced lupus affects men and women equally. The sex distribution of drug-induced lupus erythematosus is equal, whereas in SLE, women are affected more often than men.

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

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)
• Anti-histone antibody (often positive in drug-induced lupus; a histone is a protein commonly found in the cell's nucleus)

Usually, symptoms resolve within several days to weeks after stopping the medication that caused the symptoms. Nonsteroidal anti-inflammatory medications are used to treat arthritis and pleurisy.

Corticosteroid creams are used to treat skin rashes. Antimalarial drugs (hydroxychloroquine) are sometimes used for skin and arthritis symptoms. Sensitivity to light is treated by protective clothing, sunglasses, and sunscreen. Routine eye examinations are recommended to detect eye complications early.

Occasionally, the steroid prednisone is used to treat more severe cases, especially if the heart is involved. Very rarely, severe drug-induced lupus with severe cardiac involvement or significant kidney or neurologic disease requires high doses of steroids and strong medications that suppress the immune system, such as azathioprine or cyclophosphamide.

Symptoms usually resolve within several days to weeks after stopping the medication. It is essential not to restart the culprit medication at a later time, as symptoms will usually recur. Abnormal antibodies may persist for months or years despite remission.

• Infection
• Thrombocytopenia purpura -- bleeding near the skin surface, resulting�from a low number of platelets in the blood.
• Hemolytic anemia
• Myocarditis
• Pericarditis

Call for an appointment with your health care provider if symptoms do not improve after discontinuing the medication that caused the symptoms. You should also call if�new symptoms develop.

Be aware of the risk when taking medications that are known to cause this reaction. If symptoms begin to appear, consult your health care provider about the advisability of changing medication.

Harris ED, Budd RC, Genovese MC, Firestein GS, Sargent JS, Sledge CB. Kelley's Textbook of Rheumatology. 7th ed. St. Louis, Mo: WB Saunders; 2005:1183, 1598.

Noble J. Textbook of Primary Care Medicine. 3rd ed. St. Louis, Mo: Mosby. 2001:1270.