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Essentials of Diagnosis
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Localized violaceous red plaques, usually on the head (discoid lupus erythematosus) or the trunk (chronic cutaneous lupus erythematosus)
Scaling, follicular plugging, atrophy, dyspigmentation, and telangiectasia of involved areas
Distinctive histology
Photosensitivity
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General Considerations
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Common forms of cutaneous lupus
Chronic cutaneous lupus erythematosus (CCLE)
Chronic scarring lesions (discoid lupus erythematosus [DLE])
Erythematous non scarring red plaques (subacute cutaneous lupus erythematosus [SCLE])
Occur most frequently on photoexposed areas
Ten percent of patients with systemic lupus erythematosus (SLE) have discoid skin lesions, and 5% of patients with discoid lesions have SLE
In patients with DLE, consider SLE if the following findings are present
Widespread lesions (not localized to the head)
Nail fold changes (dilated or thrombosed nail fold capillary loops)
Arthralgias with or without arthritis
Positive antinuclear antibody (ANA)
Other positive serologic studies (eg, anti-double-stranded DNA or antiSmith antibody)
High erythrocyte sedimentation rate (ESR)
Proteinuria
Hypocomplementemia
The disease is persistent but not life endangering unless systemic lupus supervenes, which is uncommon
Treatment with antimalarials is effective in perhaps 60% of cases
Some medications may induce SCLE with a positive Ro/SSA, most commonly
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Usually mild
DLE lesions
Consist of violaceous red, well-localized, single or multiple plaques, 5–20 mm in diameter
Usually on the face, scalp, and external ears (conchal bowl)
There is atrophy, telangiectasia, central depigmentation or scarring, a hyperpigmented rim, and follicular plugging
Significant permanent hair loss may occur on the scalp
SCLE lesions
Are erythematous annular or psoriasiform plaques
Measure up to several centimeters in diameter
Favor the upper chest and back
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Differential Diagnosis
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SLE
Psoriasis
Seborrheic dermatitis
Acne rosacea
Lupus vulgaris (cutaneous tuberculosis)
Sarcoidosis
Bowen disease (squamous cell carcinoma in situ)
Polymorphous light eruption
Lichen planopilaris
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Diagnostic Procedures
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