Epidemiology^[3]

• The prevalence is between 17 and 48 per 100,000 people.
• Women are much more often affected than men. Discoid lupus erythematosus (DLE) usually presents in people aged between 20 and 40 years of age.

Presentation^[1]

• Red scaly patches develop which leave pigmentation, atrophy and white scars.
• The lesions are usually asymptomatic but they may present with mild pruritus or sometimes pain within the lesions.
• Discoid lupus erythematosus (DLE) mainly affects areas exposed to sunlight, such as the cheeks, nose, ears, upper back, neck and the backs of hands. It may rarely occur on the palms or soles.^[1]
• DLE lesions may become hypertrophic, causing wart-like lesions, most often on the extensor aspects of the arms.
• The scalp may be affected and cause permanent scarring alopecia.
• DLE may affect the lips and inside the mouth, causing ulcers and scaling, and predisposing to squamous cell carcinoma (SCC).

Differential diagnosis

• Systemic lupus erythematosus (SLE)
• Dermatomyositis
• Plaque psoriasis
• Actinic keratosis
• Lichen planus
• Warts
• Sarcoidosis
• Squamous cell carcinoma (SCC)
• Syphilis

Investigations^[3]

• Biopsy for histology may be required. Histopathological changes are characteristic but depend on the type and age of the lesion. Most patients with discoid lupus erythematosus (DLE) show a direct positive immunofluorescence in biopsies of lesions but this is not very specific.
• Serology: approximately 20% of patients with DLE have a positive antinuclear antibody (ANA).
• There may be a low white cell count and raised ESR.
• Rheumatoid factor may be positive.
• Complement levels may be low.
• Urinalysis may indicate renal involvement with albuminuria.

Blood tests should be repeated periodically, perhaps annually when the condition appears stable, to check for the onset of systemic disease.

Associated diseases

Porphyria cutanea tarda, lichen planus and psoriasis may be more common in patients with discoid lupus erythematosus (DLE).^[3]

Management

The mainstay of treatment includes sun protection, topical or intralesional steroids, and antimalarial drugs.

Nondrug

• Sun exposure must be minimised by avoiding going out in bright sun as much as possible, protective clothing and high factor sunscreens.
• The lesions are unsightly and usually in visible places, so cosmetic camouflage is required.

Drugs

• Corticosteroids may be used topically or intralesionally.
  • Very potent forms are necessary for hypertrophic lesions. A Cochrane review concluded that fluocinonide cream may be more effective than hydrocortisone in treating people with discoid lupus erythematosus (DLE).^[2]
  • Systemic steroids do not seem to be effective.
• When systemic treatment is required, hydroxychloroquine is the first-line agent. Hydroxychloroquine and acitretin (an oral retinoid) appear to be of equal efficacy, although adverse effects are more frequent and more severe with acitretin.^[2]
• Other possible treatments include topical retinoids and immunosuppressive agents (eg azathioprine or methotrexate).^[4]

Surgical^[3]

• Burned-out scarred lesions may be excised.
• Laser therapy can be considered for lesions with prominent telangiectasias.

Complications

• A minority of patients with discoid lupus erythematosus (DLE) (less than 5%) progress to systemic lupus erythematosus (SLE).^[3]
• Malignant degeneration (basal cell carcinoma or squamous cell carcinoma (SCC) may occur but is uncommon. Dark skin may lose its inherent protection with depigmentation.

Prognosis

Pain in lesions may continue and disfiguration from scars and atrophy will be permanent. Early treatment may reduce scarring or atrophy.