Summary
Skin, to a similar extent as the joints, represents the most common organ involved in LE either as primary manifestation or during the course of disease. Nonspecific symptoms can be separated from the distinct and specific manifestations of acute, subacute, chronic and intermitted cutaneous LE. The latter may present as a disease confined to the skin or as a manifestation of systemic disease. In several subtypes of CCLE, mild involvement of the internal organs may be present which does not suffice for diagnosing SLE. The risk of further development into systemic disease is, however, present in 5–10% of CCLE. The pathogenesis of the different CCLE entities is not as conclusively known as for ACLE and SCLE. The impact of photosensitivity is comparatively low as are evident systemic autoimmune phenomena like high titered antinuclear antibodies. Similar to systemic disease, lesional skin of CCLE is characterized by positive immune deposits at the dermo-epidermal junction. The major subtypes of CCLE can present as solitary disease or combined with other subtypes. These are discoid lupus erythematosus (DLE), hypertrophic DLE, mucous membrane DLE, chilblain lupus, lupus tumidus and lupus panniculitis / profundus. In contrast to SCLE, lesions tend to show atrophy and scarring. Typical DLE lesions are represented by sharply demarcated erythematous plaques with hyperkeratosis and follicular plugging. In lupus panniculitis, deep inflammatory processes in the dermis and subcutis result in saucer-like defects often associated with typical overlying epidermal changes. Entities most intimately associated with systemic disease are chilblain lupus and lupus panniculitis. Diagnostic procedures have to substantiate cutaneous and to exclude underlying systemic disease. Histological and immunohistochemical examinations have to be combined with autoimmune serological tests as well as additional clinical laboratory tests depending on the findings of clinical examinations. Accordingly, therapeutic measures depend on the extent of cutaneous involvement and the accompanying systemic manifestations. Early and aggressive treatment has to prevent irreversible scarring and disfiguration. Local therapy with glucocorticosteroids, retinoids, laser and cryotherapy may not suffice and has to be accompanied or substituted by systemic therapy. Antimalarial drugs, possibly in combination with short term oral glucocorticosteroids, oral retinoids, dapsone, thalidomide and supportive UV protection are the most common regimens. Alternatively, clofazimine, gold, interferons, methotrexate and azathioprine maybe used. The impact of biologics is still a matter of debate.