Onychomycosis — Pathophysiology and Multi-Modal Management
Onychomycosis is a fungal infection of the nail plate and bed, primarily caused by dermatophytes such as Trichophyton rubrum. In 2026, the clinical focus has moved from visual diagnosis to PCR-based molecular identification.
Diagnosis is classified by the site of invasion:
Distal Lateral Subungual (DLSO): The most common form, where fungi enter via the hyponychium.
Proximal Subungual (PSO): Often an early indicator of immunocompromise (e.g., HIV), as the fungus enters through the proximal nail fold.
Treatment protocols now utilize Combination Therapy. While oral Terbinafine remains the gold standard for its ability to reach the nail bed systemically, it is frequently paired with topical Efinaconazole or Urea-based debridement. This "top-down and bottom-up" approach significantly improves mycological cure rates compared to monotherapy alone.
