What are the diagnostic criteria and treatment options for discoid lupus?

Diagnosis and Treatment of Discoid Lupus Erythematosus

Hydroxychloroquine (200-400 mg daily) is the cornerstone medication for treating discoid lupus erythematosus (DLE), with topical corticosteroids as first-line therapy for localized lesions. 1

Diagnostic Criteria for Discoid Lupus Erythematosus

Clinical Features

• Well-demarcated discoid erythematous plaques with:
  • Firmly adherent scales or crusts
  • Central atrophy
  • Characteristic scarring
  • Pigmentary changes 2
• Common locations:
  • Face (81.1%)
  • Limbs (71.7%)
  • Scalp (48.4%) 3
  • Periorbital region (rare but can cause significant morbidity) 4

Histopathological Features

Skin biopsy is essential for definitive diagnosis, showing:

• Hyperkeratosis and follicular plugging
• Focal epidermal thinning
• Vacuolar alteration of the dermo-epidermal interface
• Thickened epidermal basement membrane
• Superficial and deep perivascular and periadnexal lymphocytic infiltrate
• Interstitial mucin 2

Immunopathological Features

Direct immunofluorescence (DIF) may reveal:

• Deposits of immunoglobulins (IgM and IgG most common)
• Complement at the dermo-epidermal junction 3, 2

Laboratory Findings

• Antinuclear antibody (ANA): positive in 56.6% of patients
• Anti-double-stranded DNA antibodies (anti-dsDNA): positive in 45.3% of patients 3

Treatment Options

First-Line Therapies

1. Photoprotection

   • Essential as ultraviolet radiation is the most frequent trigger (86.8% of cases) 3
   • Recommend broad-spectrum sunscreens and sun avoidance

2. Topical Therapies

   • Potent topical corticosteroids: First-line for localized lesions
     • Fluocinonide cream 0.05% is more effective than hydrocortisone 1% (27% vs 10% complete resolution) 5
   • Calcineurin inhibitors: Alternative for sensitive areas
     • Tacrolimus 0.1% cream or pimecrolimus 1% cream 5

3. Systemic Therapies

   • Hydroxychloroquine: Cornerstone medication
     • Dosage: 200-400 mg daily (single dose or divided doses) 1
     • Requires baseline and periodic ophthalmologic examinations 6

Second-Line Therapies

For refractory cases:

1. Acitretin: Similar efficacy to hydroxychloroquine (46% vs 50% complete resolution) but with more side effects 5

2. Other options for resistant cases:

   • Retinoids
   • Thalidomide
   • Immunosuppressives (azathioprine, cyclosporine, mycophenolate mofetil, methotrexate) 7

Treatment Algorithm

1. Initial Assessment:

   • Determine extent: Localized vs. disseminated
   • Assess severity and presence of scarring

2. Treatment Approach:

   • Localized DLE:

     • Potent topical corticosteroids (fluocinonide 0.05%)
     • Add hydroxychloroquine 200-400 mg daily if inadequate response

   • Disseminated DLE:

     • Start hydroxychloroquine 200-400 mg daily
     • Add topical corticosteroids for symptomatic lesions

   • Refractory Disease:

     • Consider acitretin 50 mg daily
     • Alternative: immunosuppressives or thalidomide

Monitoring and Follow-up

1. Medication Monitoring:

   • For hydroxychloroquine: Baseline and periodic ophthalmologic examinations
   • For acitretin: Monitor serum triglycerides and liver function

2. Disease Monitoring:

   • Regular assessment of skin lesions
   • Watch for progression to systemic lupus erythematosus

Important Considerations and Pitfalls

1. Diagnostic Delays:

   • DLE can present with varied manifestations, leading to significant diagnostic delays (median 38 months from symptom onset to diagnosis) 4
   • Early biopsy is recommended for unusual or refractory periocular skin disease

2. Treatment Challenges:

   • Early treatment is crucial to prevent scarring and permanent hair loss 7
   • Periorbital DLE may lead to lid deformities, trichiasis, and symblepharon if untreated 4

3. Side Effects:

   • Hydroxychloroquine: Retinal toxicity (requires ophthalmologic monitoring)
   • Acitretin: Dry lips (93%), gastrointestinal disturbance (11%), increased triglycerides 5
   • Topical tacrolimus: Burning, itching, potential herpes simplex reactivation 5

Early diagnosis and prompt treatment significantly improve prognosis and prevent irreversible scarring in patients with discoid lupus erythematosus.