# Erythema Nodosum Leprosum Triggered by Herpes Simplex Infection: A Case Report

## TL;DR

A man developed a skin condition linked to leprosy after a herpes infection, highlighting the need to consider leprosy in similar cases.

## Contribution

This case report presents a rare instance of ENL triggered by herpes simplex virus infection.

## Key findings

- The patient's rash was confirmed as ENL due to lepromatous leprosy.
- Herpes simplex virus IgM was positive, suggesting it triggered the ENL.
- Symptoms resolved with antibiotics, anti-leprosy therapy, and corticosteroids.

## Abstract

Leprosy, caused by Mycobacterium leprae, is a chronic granulomatous disease primarily affecting the skin and peripheral nerves. Erythema nodosum leprosum (ENL), or type 2 lepra reaction, is an immunologic complication of lepromatous leprosy, often presenting with erythematous nodules, fever, and systemic inflammation. Early recognition is crucial to prevent chronic complications. We report a 44-year-old man who developed facial erythematous nodules and fever following a sore throat, initially suggestive of a drug eruption or viral infection. Laboratory tests revealed neutrophilia, elevated inflammatory markers, mild transaminitis, and positive herpes simplex virus IgM. Imaging showed right periorbital soft tissue thickening. Skin biopsy confirmed lepromatous leprosy, and the rash was identified as ENL, likely triggered by acute herpes simplex virus infection. The patient received antibiotics followed by anti-leprosy therapy (dapsone, clofazimine, rifampicin) and tapering corticosteroids, with complete resolution of symptoms. This case highlights the importance of considering leprosy and its immunologic reactions in acute facial eruptions.