Question

A 13 year old male presented with erythematous edematous plaques on face over his previously existing hypoanaesthetic patches. He also complained of pain since 10 days. He has been on MBMDT since the past 2 months. What is your diagnosis?

• A. Cellulitis of face
• B. Type 1 lepra reaction
• C. Erythema Nodosum Leprosum
• D. Erysipelas

Hint:

When pre-existing leprosy skin patches become inflamed in a patient on MDT, think about the type of lepra reaction that involves pre-existing lesions.

Answer 1

The Correct Option is B

Step 1: Identify the key features of the case.
- 13-year-old male
- Erythematous, edematous (swollen) plaques on the face
- Occurring over previously existing hypoanaesthetic patches (pre-existing leprosy skin lesions with reduced sensation)
- Pain for 10 days
- Currently on MBMDT for 2 months (confirming he is a known leprosy patient)

Step 2: Apply the diagnostic criteria.
The presentation of inflammation and swelling of pre-existing hypoanaesthetic (leprosy) lesions in a patient on MDT is the hallmark of a Type 1 Lepra Reaction (Reversal Reaction).
- Type 1 reaction: caused by sudden upregulation of cell-mediated immunity (CMI) against Mycobacterium leprae antigens
- Clinical features: erythema, edema, warmth over pre-existing plaques; associated nerve involvement (nerve tenderness, pain, loss of function)
- Common in borderline leprosy
- Can occur during, before, or after MDT

Step 3: Eliminate other options.
- Cellulitis of face: bacterial infection, presents with warmth, swelling, and erythema but NOT over pre-existing hypoanaesthetic patches; no history of leprosy required.
- Erythema Nodosum Leprosum (Type 2 reaction): presents with NEW tender subcutaneous nodules (not over pre-existing patches), systemic symptoms (fever, arthralgia), occurs in lepromatous leprosy.
- Erysipelas: superficial streptococcal skin infection with sharp borders and bright red rash; not associated with hypoanaesthetic patches.

Step 4: Conclusion.
Erythematous edematous plaques over pre-existing hypoanaesthetic patches in a leprosy patient on MBMDT = Type 1 Lepra Reaction.