Discoid & Subacute Cutaneous Lupus Erythematosus

Key Features

Essentials of Diagnosis

• 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

General Considerations

• Two most common forms of chronic cutaneous lupus erythematosus (CCLE)

  • Chronic scarring lesions (discoid lupus erythematosus [DLE])

  • Erythematous non scarring red plaques (subacute cutaneous lupus erythematosus [SCLE])

• Ten percent of patients with systemic lupus erythematosus (SLE) have discoid skin lesions, and 5% of patients with discoid lesions have SLE

• 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

  • Hydrochlorothiazide

  • Calcium channel blockers

  • Angiotensin-converting enzyme (ACE) inhibitors

  • Tumor necrosis factor inhibitors

  • Terbinafine

Clinical Findings

Symptoms and Signs

• 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

Differential Diagnosis

• Psoriasis

• Seborrheic dermatitis

• Acne rosacea

• Lupus vulgaris (cutaneous tuberculosis)

• Sarcoidosis

• Bowen disease (squamous cell carcinoma in situ)

• Polymorphous light eruption

• Lichen planopilaris

Diagnosis

Laboratory Tests

• In patients with DLE, SLE should be considered if the following findings are present:

  • Positive antinuclear antibody (ANA)

  • Other positive serologic studies (eg, anti-double stranded DNA or anti-Smith antibody)

  • High erythrocyte sedimentation rate

  • Arthralgias/arthritis

  • Hypocomplementemia

  • Widespread lesions (not localized to the head)

  • Nailfold changes (dilated or thrombosed nailfold capillary loops)

• Patients with marked photosensitivity and a picture otherwise suggestive of lupus may have negative ANA tests but are positive for antibodies against Ro/SSA or La/SSB (SCLE)

Diagnostic Procedures

• Skin biopsy used to confirm diagnosis

Treatment

Medications

• See Table 6–2