What is the management for a Type 1 lepra (Hansen's disease) reaction?

Management of Type 1 Lepra Reaction

Type 1 lepra reactions should be treated with oral prednisolone at 0.5-1 mg/kg/day, with treatment duration extending beyond 12 weeks—typically 16-20 weeks or longer—as shorter courses lead to high recurrence rates and silent nerve damage. 1, 2, 3

Initial Assessment and Diagnosis

• Confirm Type 1 reaction by identifying acute onset of erythema, edema, and tenderness in existing leprosy lesions, often accompanied by new nerve function impairment 1
• Look specifically for pruritus, pain, ulceration of skin lesions, and evidence of nerve damage (sensory or motor deficits) 1
• Rule out Type 2 reaction (erythema nodosum leprosum), which presents differently with systemic symptoms and requires different management 4

Corticosteroid Therapy: The Cornerstone

Standard oral prednisolone regimen:

• Start at 0.5-1 mg/kg/day (typically 40-60 mg daily for adults) 1, 2
• Continue multidrug therapy (MDT) for leprosy concurrently—do not stop anti-leprosy treatment 1
• Treatment duration must be 16-20 weeks minimum, not the outdated 12-week WHO recommendation 2, 3
• Taper slowly over the final 4-8 weeks to prevent rebound reactions 2

Critical pitfall: The WHO's 12-week recommendation is insufficient—50% of patients require additional prednisolone despite 16 weeks of treatment, and early discontinuation causes silent nerve damage 2, 3

High-Dose Intravenous Methylprednisolone Option

For severe reactions or significant nerve function impairment:

• Consider methylprednisolone 1 gram IV daily for 3 days at treatment initiation, followed by oral prednisolone 2
• This approach reduces deterioration in sensory function between weeks 4-16 compared to oral prednisolone alone 2
• Particularly useful in Th1-mediated severe reactions with rapid nerve damage progression 2

Adjunctive and Alternative Therapies

When corticosteroids are contraindicated or cause significant side effects:

• NSAIDs and antihistamines provide symptomatic relief for pruritus and pain but are insufficient as monotherapy 1
• Thalidomide (where available and appropriate) targets pentraxin-3 and toll-like receptors 4
• Minocycline, apremilast, and other immunomodulators are emerging options for steroid-sparing regimens 4
• Plasma exchange and intravenous immunoglobulins reserved for refractory cases 4

Monitoring and Follow-Up

Essential monitoring parameters:

• Assess nerve function every 2-4 weeks during treatment, focusing on sensory testing in ulnar, median, radial, common peroneal, and posterior tibial nerves 2
• Watch for silent nerve damage even when skin lesions improve—this occurs when prednisolone is discontinued prematurely 3
• Monitor for corticosteroid side effects (hyperglycemia, hypertension, osteoporosis, psychiatric symptoms) 2
• Expect recurrence in 50% of cases—be prepared to extend or restart treatment 2

Treatment Failure and Recurrence

If symptoms persist or worsen after 4 weeks:

• Increase prednisolone dose by 0.25-0.5 mg/kg/day 1
• Consider adding methylprednisolone pulse therapy if not already given 2
• Verify medication adherence and rule out new nerve damage 2

For recurrent reactions during or after steroid taper:

• Resume prednisolone at previous effective dose 2
• Plan for longer total treatment duration (20+ weeks) 2, 3
• Consider steroid-sparing agents to minimize cumulative corticosteroid exposure 4

Key Clinical Pearls

• Type 1 reactions can occur months to years after completing MDT, so maintain vigilance even in treated patients 4
• Histoid leprosy rarely develops Type 1 reactions, but when it does, presentation may include unusual features like pruritus and ulceration 1
• The reaction represents a Th1 immune response with interferon-γ and interleukin-12 expression, explaining why aggressive immunosuppression is necessary 2
• Never stop anti-leprosy MDT when treating the reaction—continue both therapies simultaneously 1