Lepra Reactions (Immunological Crises)
Lepra reactions are acute episodes of heightened immunity in leprosy patients, representing a medical emergency that can lead to rapid nerve damage and permanent disability if not treated promptly.
Type 1 vs. Type 2 Reactions
| Feature | Type 1 (Reversal Reaction) | Type 2 (ENL) |
|---|---|---|
| Mechanism | Delayed Hypersensitivity (Type IV) | Immune Complex (Type III) |
| Spectrum | Borderline leprosy (BT, BB, BL) | Lepromatous (LL) or BL leprosy |
| Clinical Signs | Inflamed skin plaques, edema | Painful erythematous nodules (ENL) |
Management Highlights
- Type 1 Reaction: Managed primarily with high-dose Corticosteroids. Continue Multi-Drug Therapy (MDT).
- Type 2 Reaction (ENL): Drug of choice is Thalidomide (highly effective). Corticosteroids are used for severe cases. Clofazimine is helpful for chronic control.
- Nerve Involvement: Any sign of acute nerve pain or loss of function is a clear indication for systemic steroids to prevent permanent paralysis/deformity.
High-Yield Exam Pearl:
- ENL (Erythema Nodosum Leprosum): Remember the “3 F’s”: Fever, Fulminant nodules, and Frequent recurrences.
- Contraindication: Thalidomide is absolutely contraindicated in pregnancy due to severe teratogenicity.
- MDT Continuation: Crucially, never stop the leprosy treatment (MDT) during a reaction; the reaction is a response to the bacteria, not the drug.