Track

Abstract

Nontuberculous mycobacteria (NTM), environmental organisms commonly found in soil and tap water, are increasingly responsible for skin and soft tissue infections, notably including those associated with tattooing. Skin and soft tissue infections (SSTIs) caused by these environmental organisms can be challenging to diagnose. Although tissue culture is the gold standard for diagnosis, it has limitations, including long turnaround times and often indeterminate or false-negative results. This study reviews the histopathologic and staining features of tattoo-associated NTM infections. A retrospective search of the Thomas Jefferson University dermatopathology database (April 2017–July 2025) identified fifty cases of tattoo reactions. For each case, we recorded clinical impression, histopathologic findings, results of special stains (Fite-Faraco, Ziehl-Neelsen, and PAS), culture results, and clinical outcomes. Cases of confirmed NTM infection showed suppurative granulomatous inflammation with variable acid-fast positivity. In some patients, stains and cultures were negative, yet empiric antimicrobial therapy led to clinical improvement. The decision to treat empirically was based on the presence of multiple foci of eruption associated with a single ink color, acute onset following tattooing, and suppurative granulomatous dermatitis on biopsy. When these clinicopathologic features are present, they should raise suspicion for NTM SSTI and support the initiation of empiric therapy while awaiting culture results. Recognizing these patterns, considering the limitations of culture and stains, may improve clinical outcomes for tattoo-associated NTM SSTIs.