Cutaneous Atypical Mycobacterial Infections: A Brief Review.

Abstract

Nontuberculous mycobacterial (NTM) infections are increasingly recognized, particularly in tropical regions and are often found in immunocompetent individuals. These infections are emerging as significant health concerns, especially pulmonary NTM, which is reported more frequently and is known to be associated with hospital environments. While pulmonary NTM infections are on the rise, partly due to drug resistance and possible patient-to-patient transmission, there is no current evidence indicating an increase in cutaneous NTM infections. The clinical manifestations of NTM infections, except for well-known entities like Buruli ulcer and fish tank granuloma, are diverse and nonspecific, often mimicking other chronic infections. History of minor trauma at the site of infection can be misleading and may complicate the diagnosis of cutaneous NTM. Surgical-site and port-site NTM infections typically present with erythema, edema, and abscesses and are commonly caused by rapidly growing mycobacteria like M. fortuitum and M. chelonae. These infections may not respond to standard antibiotics, suggesting the need for NTM-specific treatment. Diagnostically, histopathology may not be conclusive, and standard staining techniques often lack sensitivity. Molecular methods offer better speciation and drug resistance profiling for pulmonary NTM but are expensive and not widely available for cutaneous forms. The high cost and limited availability of diagnostic tools necessitate an empirical treatment approach, which is also recommended by the INDEX-Tb guidelines for extrapulmonary tuberculosis. Empirical treatment regimens for NTM, such as combinations of clarithromycin, doxycycline, and cotrimoxazole or fluoroquinolones, have shown promise, but there is a lack of rigorous studies to establish standardized treatments. Monitoring for adverse effects and continued evaluation of the causative organism is essential during empirical treatment, allowing for adjustment if the initial regimen fails.