Onychomycosis Caused by Neoscytalidium Dimidiatum: An Emerging Disease

Purpose of Review This review aims to synthesize current evidence on Neoscytalidium dimidiatum onychomycosis, an emerging non-dermatophyte infection that increasingly challenges diagnostic accuracy and therapeutic success. We seek to clarify its taxonomic characteristics, clinical presentation, epidemiology, and resistance patterns, addressing how clinicians can better identify and manage this difficult-to-treat pathogen. Recent Findings Neoscytalidium dimidiatum has increasingly been acknowledged as a cause of onychomycosis and superficial dermatomycoses, particularly in tropical and subtropical areas. Its dual synanamorphs and rapid growth yield darkly pigmented colonies and mixed hyaline dematiaceous hyphae. Clinically, it mimics dermatophyte onychomycosis but often shows gray-black discoloration, multinail involvement, and marked resistance to standard antifungals. Summary Current evidence indicates that N. dimidiatum represents a growing global threat due to environmental exposure and inherent antifungal resistance. Accurate recognition, mycological confirmation, and tailored combination therapy are essential to improving outcomes.