# Clinico‐Epidemiological and Molecular Evidences for Reactivation of Herpesviruses in Dapsone‐Induced Hypersensitivity Reactions in Nepalese Leprosy Patients: An Observational Study

## TL;DR

This study explores how herpesviruses may be linked to severe allergic reactions in leprosy patients taking dapsone, with symptoms recurring about 20 days after stopping the drug.

## Contribution

The study provides clinical and molecular evidence linking herpesvirus reactivation to dapsone hypersensitivity in Nepalese leprosy patients.

## Key findings

- 71% of patients experienced symptom relapse ~20 days after stopping dapsone.
- 39% of patients had detectable herpesviruses (HHV-5 or HHV-6) in their blood samples.
- Reflare was associated with more abnormal lab values, though not statistically significant.

## Abstract

Dapsone hypersensitivity (DHS) is a potentially fatal and severe cutaneous adverse reaction that occurs in patients taking dapsone. As leprosy, for which dapsone is used as part of multidrug therapy, usually occurs in countries with resource limitations, the morbidity and mortality caused by DHS are more dreadful. Herpesviruses (especially HHV‐5 and 6) are frequently associated with the etiology of drug‐induced hypersensitivity reactions, and the reactivation of these viruses coincides with the reflare of clinical symptoms even after the cessation of culprit drugs.

We reviewed the hospital charts of patients (Cohort 1) with DHS who were admitted to our hospital at the time of the DHS episode. Similarly, we examined the presence of HHV‐5 and 6 in another independent group of DHS blood samples (Cohort 2) by PCR.

Seventy‐one percent (71%, 17/24) of DHS patients experienced recrudescence (reflare) of symptoms ~20 days after cessation of dapsone in Cohort 1. In Cohort 2, 39% (13/33) of blood samples from DHS patients showed the presence of at least one herpesvirus.

In this exploratory study, our data suggest the role of herpesviruses in the natural history of DHS and identify patterns that support future hypothesis‐driven investigations into antiviral treatment strategies for the management of DHS cases, with the potential to reduce morbidity and mortality.

This study found clinical and molecular evidences for the presence of herpesvirus (HHV‐5 and HHV‐6) reactivation during dapsone‐induced hypersensitivity in Nepalese leprosy patients. Reflare of hypersensitivity symptoms occurred on average 20 days after culprit drug cessation. Patients with reflare (71%) had more abnormal laboratory values (but not statistically significant).