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Discoid Lupus Erythematosus: Clinical Overview

Discoid lupus erythematosus (DLE) is the most common form of chronic cutaneous lupus erythematosus, characterized by inflammatory, scarring plaques with adherent scales, follicular plugging, central atrophy, and irreversible scarring alopecia, predominantly affecting sun-exposed areas of the face, scalp, and ears. 1, 2

Clinical Presentation

Characteristic Lesion Morphology

• DLE presents as well-demarcated, round or oval erythematous plaques with firmly adherent scales or crusts, follicular plugging, central atrophy, and characteristic scarring with pigmentary changes. 1, 2
• Long-standing lesions develop atrophy, scarring, hypopigmentation, hyperpigmentation, and telangiectasias. 2
• On the face, lesions can form a butterfly-like distribution involving the cheeks and nose. 2

Distribution Patterns

• Localized DLE (67.9% of cases) affects the head and neck, particularly the face (81.1%), scalp (48.4%), and auricles. 3
• Disseminated DLE (DDLE) extends beyond the head and neck to involve the trunk, limbs (71.7%), and other photoexposed areas. 1, 3
• The scalp involvement frequently results in permanent scarring alopecia. 1

Epidemiology and Risk Factors

• DLE demonstrates a strong female predominance with a male-to-female ratio of 1:3.1, with mean age of presentation at 36 years. 3
• Ultraviolet radiation exposure is the most frequent triggering factor (86.8% of cases), followed by stress (26.4%) and smoking (particularly in males at 53.8%). 3
• Approximately 20.8% of patients have a positive family history. 3

Diagnostic Approach

Clinical Assessment

• Document the precise morphology, distribution, and extent of skin lesions to classify them as localized versus disseminated DLE. 4
• Assess for photosensitivity history and identify triggering factors including UV exposure, smoking, and stress. 3
• Evaluate for systemic lupus erythematosus (SLE) features, as 5-10% of DLE patients may develop systemic disease. 5

Laboratory Workup

• Order comprehensive autoantibody panel including ANA (positive in 56.6% of DLE), anti-dsDNA (positive in 45.3%), anti-Ro/SSA, anti-La/SSB, anti-RNP, and anti-Sm. 4, 3
• Measure complement levels (C3, C4) to assess for systemic involvement. 5, 4
• Obtain complete blood count, serum creatinine, proteinuria, and urine sediment to screen for renal involvement. 5

Histopathological Confirmation

• Perform skin biopsy from the most active erythematous or sclerotic portion of the lesion while clinically visible, as sampling after healing markedly reduces diagnostic yield. 4, 1
• Histopathological features include hyperkeratosis, follicular plugging, focal epidermal thinning, vacuolar alteration of the dermo-epidermal interface, thickening of the epidermal basement membrane, and superficial and deep perivascular and periadnexal lymphocytic infiltrate with interstitial mucin. 1, 3
• Direct immunofluorescence reveals deposits of IgM and IgG (most common) at the dermo-epidermal junction. 1, 3

Treatment Algorithm

First-Line Therapy

• Initiate strict photoprotection with SPF 60+ broad-spectrum sunscreen, sun avoidance during peak hours (10 AM-4 PM), and protective clothing/hats as mandatory for all patients. 5, 6
• Apply medium- to high-potency topical corticosteroids (triamcinolone or clobetasol) to affected areas twice daily; use low-potency hydrocortisone on facial lesions to avoid skin atrophy. 5
• Topical calcineurin inhibitors (tacrolimus 0.1% ointment or pimecrolimus 1% cream) can be used as an alternative to topical corticosteroids, particularly for facial involvement, applied twice daily for 4-8 weeks. 7, 5, 8, 9

Systemic Therapy

• Hydroxychloroquine should be initiated in all DLE patients at a dose not exceeding 5 mg/kg real body weight, as it is the cornerstone of systemic treatment. 5, 4, 6
• Regular ophthalmological screening must be performed at baseline, after 5 years, and yearly thereafter to monitor for retinal toxicity. 5
• Counsel smoking cessation aggressively, as smoking impairs antimalarial response and worsens cutaneous lupus. 4, 6

Second-Line and Refractory Disease

• For non-responsive cases or those requiring high-dose glucocorticoids, add methotrexate, dapsone (particularly effective for bullous lupus), retinoids (for hyperkeratotic lesions), or mycophenolate mofetil. 7, 5
• Systemic glucocorticoids should be minimized to less than 7.5 mg/day (prednisone equivalent) for chronic maintenance and withdrawn when possible. 7, 5
• Prompt initiation of immunomodulatory agents expedites glucocorticoid tapering and discontinuation. 7, 5

Monitoring and Follow-Up

Disease Activity Assessment

• Use the Cutaneous Lupus Disease Area and Severity Index (CLASI) to quantify disease activity and damage at baseline and follow-up visits. 4
• Monitor every 6-12 months with CBC, ESR, CRP, serum creatinine, urinalysis, anti-dsDNA, C3, and C4 levels. 4
• Repeat anti-dsDNA and complement levels at follow-up visits even if previously negative, as some patients develop these markers during flares. 4

Comorbidity Prevention

• Prescribe calcium (1000-1200 mg daily) and vitamin D supplementation (800-1000 IU daily) for all patients on chronic glucocorticoid therapy to prevent bone loss. 4, 6
• Assess and aggressively manage cardiovascular risk factors (blood pressure, LDL cholesterol, fasting glucose, BMI) at baseline and annually, as SLE patients have markedly increased cardiovascular disease risk. 5, 6
• Consider low-dose aspirin for primary prevention in patients with antiphospholipid antibodies or multiple cardiovascular risk factors. 5, 6

Critical Pitfalls to Avoid

• Never delay skin biopsy until the lesion has completely healed, as nonspecific histologic findings will fail to confirm diagnosis. 4
• Avoid prescribing estrogen-containing contraceptives to patients with antiphospholipid antibodies, as this dramatically increases thrombosis risk. 5, 6
• Do not rely on serological activity alone to intensify therapy without clinical correlation, as this risks overtreatment. 4
• Avoid prolonged high-dose glucocorticoids (>7.5 mg/day) chronically without implementing steroid-sparing strategies, as this accelerates cardiovascular damage, osteoporosis, and avascular necrosis. 5, 6
• Never discontinue hydroxychloroquine unless there is a specific contraindication, as it reduces disease activity, flares, organ damage, and mortality. 5, 6