# Hemophagocytic Lymphohistiocytosis Unmasking Systemic Lupus Erythematosus: Management With Belimumab and a Case Study

## TL;DR

A previously healthy woman developed hemophagocytic lymphohistiocytosis (HLH) as the first sign of systemic lupus erythematosus (SLE) and was successfully treated with a combination including belimumab.

## Contribution

This case study presents a rare instance where HLH unmasked SLE and demonstrates the successful use of belimumab in treatment.

## Key findings

- HLH can be the initial manifestation of an underlying rheumatological condition like SLE.
- The patient showed complete recovery after treatment with dexamethasone, etoposide, and belimumab.
- Belimumab may be an effective treatment option for SLE-related HLH.

## Abstract

Secondary hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory condition caused by the hyperactivation of macrophages and T-cells, triggered by infection, malignancy, or underlying rheumatological conditions. It rarely presents as a first manifestation of a rheumatological condition. Macrophage activation syndrome (MAS) is secondary HLH associated with underlying hematological conditions. Here, we present a case of a previously healthy 29-year-old female who was admitted with fever, rash, and pancytopenia, found to have HLH, and a workup revealed underlying systemic lupus erythematosus (SLE). She was successfully treated with dexamethasone, etoposide, and belimumab, with complete recovery of her symptoms. This case highlights the importance of a thorough evaluation of rheumatological conditions in all patients with HLH despite their previous medical history and the use of belimumab for SLE.