Cutaneous lupus erythematosus: issues in diagnosis and treatment.

Cutaneous lupus erythematosus (LE) may present in a variety of clinical forms. Three recognized subtypes of cutaneous LE are acute cutaneous LE (ACLE), subacute cutaneous LE (SCLE), and chronic cutaneous LE (CCLE). ACLE may be localized (most often as a malar or 'butterfly' rash) or generalized. Multisystem involvement as a component of systemic LE (SLE) is common, with prominent musculoskeletal symptoms. SCLE is highly photosensitive, with predominant distribution on the upper back, shoulders, neck, and anterior chest. SCLE is frequently associated with positive anti-Ro antibodies and may be induced by a variety of medications. Classic discoid LE is the most common form of CCLE, with indurated scaly plaques on the scalp, face, and ears, with characteristic scarring and pigmentary change. Less common forms of CCLE include hyperkeratotic LE, lupus tumidus, lupus profundus, and chilblain lupus. Common cutaneous disease associated with, but not specific for, LE includes vasculitis, livedo reticularis, alopecia, digital manifestations such as periungual telangiectasia and Raynaud phenomenon, photosensitivity, and bullous lesions. The clinical presentation of each of these forms, their diagnosis, and the inter-relationships between cutaneous LE and SLE are discussed. Common systemic findings in SLE are reviewed, as are diagnostic strategies, including histopathology, immunopathology, serology, and other laboratory findings. Treatments for cutaneous LE initially include preventive (e.g. photoprotective) strategies and topical therapies (corticosteroids and topical calcineurin inhibitors). For skin disease not controlled with these interventions, oral antimalarial agents (most commonly hydroxychloroquine) are often beneficial. Additional systemic therapies may be subdivided into conventional treatments (including corticosteroids, methotrexate, thalidomide, retinoids, dapsone, and azathioprine) and newer immunomodulatory therapies (including efalizumab, anti-tumor necrosis factor agents, intravenous immunoglobulin, and rituximab). We review evidence for the use of these medications in the treatment of cutaneous LE.