# Mycobacterium abscessus Hand Infection Mimicking Dactylitis Due to Spondyloarthritis: A Case Report

## TL;DR

A 73-year-old woman's hand infection was initially mistaken for arthritis but was later found to be caused by Mycobacterium abscessus.

## Contribution

This case report highlights the rare musculoskeletal presentation of M. abscessus mimicking spondyloarthritis.

## Key findings

- The patient's symptoms were initially misdiagnosed as seronegative spondyloarthritis due to dactylitis.
- Synovial biopsy confirmed a M. abscessus subspecies infection.
- The case emphasizes the need to consider atypical infections in arthritis-like presentations.

## Abstract

Mycobacterium abscessus is an environmental, rapid-growing non-tuberculosis Mycobacterium commonly found in soil and water. While typically causing pulmonary infections, it can present with musculoskeletal manifestations that mimic inflammatory arthritis. We present a case of a 73-year-old woman who developed progressive hand tenosynovitis following a gardening injury. The clinical presentation initially suggested seronegative spondyloarthritis, particularly due to the presence of dactylitis. However, synovial biopsy and culture ultimately revealed M. abscessus subsp. abscessus infection. This case highlights the importance of considering atypical infections in the differential diagnosis of apparent inflammatory arthritis, especially with unilateral involvement and inadequate response to conventional therapy.