Discoid & Subacute Lupus Erythematosus

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

• Photosensitivity

• Distinctive histology

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

Symptoms and Signs

• Usually mild

• DLE lesions

  • Consist of violaceous red, well-localized, single or multiple plaques

  • Measure 5–20 mm in diameter

  • Usually appear on the face, scalp, and external ears (conchal bowl)

  • Significant permanent hair loss may occur on scalp

  • Other characteristics

    • Atrophy

    • Telangiectasia

    • Central depigmentation or scarring

    • A hyperpigmented rim

    • Follicular plugging

• 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

Laboratory Tests

• In patients with DLE, the possibility of 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

  • Proteinuria

  • Hypocomplementemia

  • Widespread lesions (not localized to the head)

  • Nailfold changes (dilated or thrombosed nailfold capillary loops)

  • Arthralgia with or without arthritis

• Patients with marked photosensitivity and symptoms 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

Medications

• See Table 6–2

General measures

• Use photoprotective clothing and broad-spectrum sunblock with SP 30 or more

• UVA coverage is essential in photosensitive patients

• Avoid using drugs that are potentially photosensitizing (eg, doxycycline) when possible

• Caution: Do not use any form of radiation therapy

Local treatment

• High-potency corticosteroid creams applied each night and covered with airtight plastic film (eg, Saran Wrap) or Cordran tape; or ultra-high-potency corticosteroid cream or ointment applied twice daily without occlusion

• Local infiltration

  • Triamcinolone acetonide suspension, 2.5–10 mg/mL, may be injected into the lesions of DLE once a month

Systemic treatment

• Caution: The antimalarials (hydroxychloroquine sulfate, chloroquine sulfate and quinacrine) should be used only when the diagnosis is secure because they have been associated with flares of psoriasis, which is in the differential diagnosis

• Hydroxychloroquine sulfate

  • Daily dose of no more than 5 mg/kg orally (real-weight)

  • May be effective

  • Often used prior to chloroquine

  • A minimum 3-month trial is recommended

  • Screening for ocular toxicity is needed

• Chloroquine sulfate, 250 mg orally daily, may be effective in some cases where hydroxychloroquine is not

• Isotretinoin, 1 mg/kg/day orally, is effective in hypertrophic DLE lesions

• Thalidomide

  • Effective in refractory cases

  • Dose: 50–300 mg orally daily

  • Monitor for neuropathy

• Lenalidomide

  • May also be effective in refractory cases

  • Dose: 5–10 mg orally daily

  • Less risk of neuropathy than thalidomide

Follow-Up

• Isotretinoin, thalidomide, and lenalidomide

  • Teratogens

  • Should be used with appropriate contraception and monitoring in women of childbearing age

• Patients with cutaneous LE should be examined and tested annually (complete blood count and urinalysis) to screen for early signs of systemic involvement

Complications

• Although the only morbidity may be cosmetic, this can be of overwhelming significance in more darkly pigmented patients with widespread disease

• Scarring alopecia can be prevented or lessened with close attention and aggressive therapy

Prognosis

• The disease is persistent but not life endangering unless systemic lupus is present

• Treatment with one or more antimalarials is effective in more than half of cases

• Over years, DLE tends to become inactive

• Drug-induced SCLE usually resolves over months when the inciting medication is stopped

When to Refer

• There is a question about the diagnosis

• Recommended therapy is ineffective

• Specialized treatment is necessary