Lupus Erythematosus
A chronic inflammatory autoimmune disorder affecting the connective tissues, lupus erythematosus takes two forms: discoid lupus erythematosus (DLE) and systemic lupus erythematosus (SLE). DLE affects only the skin (see Discoid lupus erythematosus, page 544), whereas SLE affects multiple organs (including the skin) and can be fatal.
Researchers think that clinical signs and symptoms result from antibody-antigen trapping in specific organ capillaries. Like rheumatoid arthritis, SLE is characterized by recurrent seasonal remissions and exacerbations, especially during the spring and summer.
SLE strikes females 8 times more often than males (15 times more often during childbearing years). SLE occurs worldwide but is most prevalent among Asians and Blacks.
The prognosis improves with early detection and treatment but remains poor for patients who have cardiovascular, renal, or neurologic complications or severe bacterial infections.
Causes
The exact cause of SLE remains a mystery, but available evidence points to interrelated immune, environmental, hormonal, and genetic factors. Scientists think that autoimmunity is the primary cause. In autoimmunity, the body produces antibodies, such as antinuclear antibodies (ANAs), against its own cells. The formed antigen-antibody complexes then suppress the body’s normal immunity and damage tissues. A significant feature in patients with SLE is their ability to produce antibodies against many different tissue components, such as red blood cells (RBCs), neutrophils, platelets, lymphocytes, or almost any organ or tissue in the body.
Certain predisposing factors may make a person susceptible to SLE. These include stress, streptococcal or viral infections, exposure to sunlight or ultraviolet light, immunization, pregnancy, and abnormal estrogen metabolism.
Complications
Pulmonary abnormalities can result in pleurisy, pleural effusion, pneumonitis, pulmonary hypertension, and pulmonary infections. Cardiac involvement can include pericarditis, myocarditis, endocarditis, and coronary atherosclerosis. Renal disease can progress to renal failure.
Seizures and mental dysfunction can result.
Discoid lupus erythematosus
A form of lupus erythematosus marked by chronic skin eruptions, discoid lupus erythematosus (DLE) can cause scarring and permanent disfigurement if untreated. About 5% of patients with DLE later develop systemic lupus erythematosus (SLE). An estimated 60% of patients with DLE are females in their late 20s or older. The disease seldom occurs in children. Its exact cause isn’t known, although evidence suggests an autoimmune process.
Assessment
The patient with DLE has lesions that appear as raised, red, scaling plaques with follicular plugging and central atrophy. The raised edges and sunken centers give the lesions a coinlike appearance. Although these lesions can appear anywhere on the body, they usually erupt on the face, scalp, ears, neck, and arms or on any part of the body that is exposed to sunlight. Such lesions can resolve completely or may cause hypopigmentation or hyperpigmentation, atrophy, and scarring. Facial plaques sometimes assume the butterfly pattern characteristic of SLE. Hair becomes brittle and may fall out in patches.
Diagnostic tests
As a rule, the patient’s history and the rash are enough to form the diagnosis. Positive findings in the lupus erythematosus (LE) cell test (in which polymorphonuclear leukocytes engulf cell nuclei to form s0-called LE cells) occur in less than 10% of patients. Positive lesional skin biopsy results typically disclose immunoglobulins or complement components. SLE must be ruled out.
Treatment
Patients with DLE must avoid prolonged exposure to the sun, fluorescent lighting, and reflected sunlight. They should wear protective clothing, use sunscreen, avoid outdoor activity during peak sunlight periods (between 10 a.m. and 2 p.m.), and report any changes in the lesions.
As in SLE, drug treatment consists of topical, intralesional, and systemic medications.
Assessment
The onset of SLE, which may be acute or insidious, produces no characteristic clinical pattern. However, the patient may complain of fever, anorexia, weight loss, malaise, fatigue, abdominal pain, nausea, vomiting, diarrhea, constipation, rashes, and polyarthralgia. When taking the patient history, be sure to check the medication and drug history because many medications can cause an SLE-like reaction.
SLE can involve every organ system. Females may report irregular menstruation or amenorrhea, particularly during flareups. In about 90% of patients, joint involvement resembles that of rheumatoid arthritis. Raynaud’s phenomenon affects about 20% of patients. The patient may complain that sunlight (or ultraviolet light) provokes or aggravates skin eruptions. She may report chest pain (indicating pleuritis) and dyspnea (suggesting parenchymal infiltrates and pneumonitis).
Cardiopulmonary signs and symptoms occur in about 50% of patients. Watch for repeated arterial clotting to manifest itself in dyspnea, tachycardia, central cyanosis, and hypotension. These signs and symptoms may herald pulmonary emboli. Also be alert for altered level of consciousness, weakness of the extremities, and speech disturbances that point to cerebrovascular accident.
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