Discoid Lupus Erythematosus

Discoid lupus erythematosus (DLE) is the most common form of chronic cutaneous lupus, causing well defined erythematous scaly plaques with follicular plugging that heal with atrophic scarring and dyspigmentation.

• Incidence is 3 to 5 per 100,000. Peak onset 20 to 50 years; women 2 to 3 times more than men. Higher prevalence and scarring in Black patients.
• About 5 to 10% of localised DLE (up to 20% of generalised) progress to SLE.
• Triggers: UV light, smoking, trauma (Koebner), and drugs.
• Risk of squamous cell carcinoma in chronic scarred lesions (rare).

• Sharply demarcated, erythematous to violaceous, adherent scaly plaques with follicular plugging ("carpet tack" sign), telangiectasia, and central atrophy and hypopigmentation with peripheral hyperpigmentation.
• Sites: face (cheeks, nose, ears), scalp (scarring alopecia), and neck; generalised DLE involves trunk and arms.
• Oral discoid lesions, hypertrophic (verrucous) DLE, lupus panniculitis (profundus) variant.
• Mostly asymptomatic or mild itch/burning.

• Biopsy: interface dermatitis with hyperkeratosis, follicular plugging, basement membrane thickening, and periadnexal lymphocytic infiltrate; DIF (lupus band) positive in lesional skin in about 60 to 90%.
• Baseline labs: FBC, ESR, creatinine, urinalysis, ANA (positive in about 30 to 50%), anti-dsDNA, ENA (anti-Ro, anti-La), complements, and antiphospholipid antibodies.
• Exclude SLE (ACR/EULAR criteria), lichen planus, actinic keratosis, sarcoidosis, tinea, cutaneous lymphoma, and Jessner lymphocytic infiltrate.
• Annual screening for systemic disease.

• Photoprotection: broad spectrum SPF 50+ sunscreen, protective clothing, and avoidance of peak sun; check vitamin D and supplement.
• Smoking cessation (smoking reduces antimalarial response).
• Topical: clobetasol 0.05% ointment twice daily for 2 to 4 weeks on body (weaker steroids on face), tacrolimus 0.1% ointment or pimecrolimus on face, intralesional triamcinolone 5 to 10 mg/mL.
• Systemic first line: hydroxychloroquine 200 mg twice daily (maximum 5 mg/kg/day actual body weight) with annual retinal screening after 5 years (earlier if renal impairment or high dose); quinacrine 100 mg daily added if hydroxychloroquine is inadequate (not widely available).
• Second line: methotrexate 15 to 25 mg weekly, mycophenolate 1 to 2 g daily, acitretin 25 to 50 mg daily, dapsone 50 to 100 mg, thalidomide 50 to 100 mg daily (contraception, neuropathy, thrombosis risk), or belimumab and anifrolumab if SLE overlap.
• Monitoring for SLE evolution and biopsy of non-healing ulcers for squamous cell carcinoma; camouflage cosmetics and laser for telangiectasia.