Discoid lupus erythematosus is an autoimmune disease related to systemic lupus erythematosus (SLE), but although SLE usually affects multiple organ systems, discoid lupus primarily affects the skin. The causes of discoid lupus are not completely understood, but because the disease does tend to run in families, experts believe that there is a genetic component. The disease affects two to three times as many women as men, and up to 10 percent of discoid lupus suffers ultimately develop SLE. Discoid lupus symptoms are characterized by a red scaly rash that can develop into a disc-shaped sore that slowly expands outward.
Symptoms of discoid lupus most often develop on areas of the skin exposed to sunlight, but they can appear anywhere. When the disease is limited to the head and neck, it is referred to as localized discoid lupus, but when discoid lupus symptoms appear on other areas of the body, it is referred to as widespread discoid lupus. Discoid lupus sores can cause scarring, and lesions that occur on areas of the skin covered by hair can cause permanent hair loss. Exposure to sunlight can trigger discoid lupus symptoms in photosensitive people, even on areas of the skin that weren't exposed to sunlight. Cigarette smoking is also believed to trigger symptoms.
Physicians diagnose discoid lupus with a physical examination and a skin biopsy. If the biopsy confirms discoid lupus, patients are often tested for SLE to make sure that no other organ systems are involved. If patients test negative for SLE, they are generally retested every six to 12 months. Individuals with discoid lupus who do develop SLE usually suffer from a relatively mild manifestation of the systemic disease. People who develop discoid lupus earlier, those who suffer from widespread rather than localized discoid lupus and those who develop more sores are more likely to develop SLE.
Discoid lupus symptoms are usually treated with topical corticosteroids. If that proves ineffective, cortisone shots can be administered directly into sores. Calcineurin inhibitors, pimecrolimus cream, tacrolimus ointment and antimalarials such as hydroxychloroquine can also be used to treat discoid lupus, but physicians generally try to avoid prescribing hydroxychloroquine because it can cause irreversible damage to the retina. Individuals taking hydroxychloroquine must undergo routine eye and blood tests to monitor the effects of the medication. Individuals can help prevent discoid lupus symptoms by using sunscreen that protects against both ultraviolet A and ultraviolet B light and by wearing protective clothing and hats.