Different Forms of Lupus
المؤلف:
Mary Louise Turgeon
المصدر:
Immunology & Serology in Laboratory Medicine
الجزء والصفحة:
5th E, P407-409
2025-09-29
151
There are several forms of lupus, including discoid, systemic, drug-induced, and neonatal lupus.
Discoid (cutaneous) lupus is always limited to the skin and is identified by biopsy of the rash that may appear on the face, neck, and scalp. Discoid lupus does not generally involve the body’s internal organs but can evolve into the systemic form of the disease, even if treated. Evolution to systemic lupus cannot be predicted or prevented. The antinuclear antibody (ANA) test may be negative or positive at a low titer. Discoid lupus accounts for approximately 10% of all cases of lupus.
Systemic lupus is usually more severe than discoid lupus and can affect the skin, joints, and almost any organ or body system, including the lungs, kidneys, heart, and brain. Systemic lupus may include periods in which few, if any, symptoms are evident (remission) and other times when the disease becomes more active (flare). Most often, when people mention “lupus,” they are referring to the systemic form of the disease. Approximately 70% of lupus cases are systemic. In about 50% of these cases, a major organ will be affected.
Drug-induced lupus occurs after the use of certain pre scribed drugs (Box 1). The most frequently used drugs associated with drug-induced lupus are hydralazine hydrochloride and procainamide hydrochloride. Factors such as the rate of drug metabolism, the drug’s influence on immune regulation, and the host’s genetic composition are all believed to influence pathogenesis. Some drugs (e.g., oral contraceptives, isoniazid) induce serum antinuclear antibodies (ANAs) without symptoms. High antibody titers may exist for months without the development of clinical symptoms.
Box1. Drugs That Can Produce Clinical and Serologic Features of Systemic Lupus Erythematosus
Procainamide-induced disease does not induce antibodies to double-stranded deoxyribonucleic acid (dsDNA). The ANAs in the drug-induced syndromes are histone-dependent and are never the only ANAs present in the blood. Even with discontinuation of the drug, antibody titers usually remain elevated for months or years.
Only about 4% of patients who take these drugs will develop the antibodies suggestive of lupus. Of those 4%, only an extremely small number will develop overt drug-induced lupus. The symptoms of drug-induced lupus are similar to those of systemic lupus, but milder. Patients with drug-related lupus have a predominance of pulmonary and polyserositic signs and symptoms. Patients with drug-induced lupus have no associated renal or central nervous system (CNS) disease. In addition, lupus inducing drugs do not appear to exacerbate idiopathic SLE. The symptoms usually fade when the medications are discontinued.
Neonatal lupus is a rare condition acquired from the passage of maternal autoantibodies, specifically anti-Ro/SS-A or anti La/SS-B, that can affect the skin, heart, and blood of the fetus and newborn. Neonatal lupus is associated with a rash that appears within the first several weeks of life and may persist for about 6 months before disappearing. Congenital heart block can occur but is much less common than a rash. Neonatal lupus is not systemic lupus.
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