Treatment of Leprosy Reactions and Dapsone Hypersensitivity Syndrome
For Type 1 reversal reactions, initiate prednisone immediately to prevent irreversible nerve damage; for Type 2 erythema nodosum leprosum, use thalidomide as first-line (where available) or prednisone as alternative; and for dapsone hypersensitivity syndrome, discontinue dapsone permanently and treat with systemic corticosteroids within 24 hours of recognition. 1, 2
Type 1 Reversal Reaction Management
Prednisone is the cornerstone of treatment for Type 1 reversal reactions, as these reactions represent the most common cause of nerve damage in leprosy and require urgent intervention. 1
Treatment Protocol:
- Start prednisone 0.5-1 mg/kg body weight for acute reversal reactions with nerve function impairment 2
- Continue treatment for 7 days at full dose, then taper over 4-6 weeks to prevent rebound 2
- 88.2% of patients achieve complete or partial recovery of nerve function when treated promptly with prednisolone 3
Critical Timing Considerations:
- Reversal reactions occur most frequently during the first year of multidrug therapy (26.3% of borderline lepromatous patients) 3
- Risk persists through the fifth year of treatment, requiring ongoing vigilance 3
- Reactions may present before, during, or after completion of multidrug therapy 1
Monitoring Requirements:
- Assess nerve function weekly during the first 8 weeks of treatment 4
- Watch for progressive nerve damage, which mandates immediate corticosteroid escalation 1
Type 2 Erythema Nodosum Leprosum (ENL) Management
Thalidomide represents first-line therapy for ENL where available, with prednisone serving as the alternative when thalidomide is contraindicated or unavailable. 1
Treatment Algorithm:
- Thalidomide: Preferred agent for ENL due to specific anti-inflammatory effects in this condition 1
- Prednisone 0.5-1 mg/kg body weight: Use when thalidomide is contraindicated (pregnancy, women of childbearing potential without strict contraception) 1, 2
- ENL occurs less frequently than reversal reactions (11.1% of lepromatous patients by second year of treatment) but can also cause neuritis requiring aggressive management 3, 1
Clinical Recognition:
- ENL typically manifests during the first year of multidrug therapy (5.5% of lepromatous patients) 3
- Peak incidence occurs in lepromatous and borderline lepromatous disease categories 1
Dapsone Hypersensitivity Syndrome (DHS) Management
Immediate discontinuation of dapsone is mandatory, as DHS represents one of the major causes of death in leprosy patients and requires emergency intervention. 4, 5
Emergency Protocol:
- Stop dapsone permanently at first suspicion of DHS 2, 5
- Initiate systemic corticosteroids within 24 hours of recognition, as early treatment improves outcomes 2
- DHS typically presents 1-4 weeks (classically 6-8 weeks) after starting dapsone 6, 5
Clinical Recognition Features:
- Fever, exfoliative dermatitis, hepatic dysfunction, and methemoglobinemia 6
- May occur concurrently with Type 1 reactions, complicating diagnosis 5
- Never rechallenge with dapsone after confirmed DHS 2
Prevention Strategy:
- HLA-B*13:01 screening before initiating dapsone in high-risk populations (particularly Chinese ancestry) can prevent DHS entirely 4
- Prospective screening reduced DHS incidence from expected 1.0% to 0% in HLA-B*13:01-negative patients 4
- Carriers of HLA-B*13:01 (17.3% of tested population) should receive alternative multidrug therapy without dapsone 4
Alternative Treatment After DHS:
- Continue rifampin and clofazimine without dapsone 4
- Adjust multidrug therapy regimen to exclude all sulfone-containing medications 4
Critical Safety Considerations
Corticosteroid Monitoring:
- Document baseline complete blood counts and liver function before initiating prednisone 7
- Monitor for infection risk, particularly in elderly patients where high-dose immunosuppression may be more dangerous than the underlying condition 7
- Avoid applying topical corticosteroids to open wounds or erosions; use only on intact skin 8
Common Pitfalls to Avoid:
- Do not delay corticosteroid treatment while awaiting definitive diagnosis of reversal reaction, as nerve damage is often irreversible 1, 3
- Do not continue dapsone if DHS is suspected, even if symptoms are mild initially 2, 6
- Do not use prophylactic corticosteroids or antihistamines to prevent reactions, as this approach is ineffective and may increase risk 2