lonychomycose

Lonychomycose, commonly referred to as onychomycosis in medical literature, is a fungal infection of the nail apparatus, affecting one or more nails. It most often involves the toenails but can involve fingernails, and it tends to be chronic and slowly progressive.

The infection is caused by dermatophytes, with Trichophyton rubrum being the most frequent organism, though nondermatophyte molds and Candida species can also be responsible. Transmission occurs through direct contact with contaminated surfaces, nails of infected individuals, or communal facilities. Risk factors include advanced age, diabetes, peripheral vascular disease, immunosuppression, nail trauma, and prolonged exposure to moist environments or occlusive footwear.

Common symptoms include nail thickening, discoloration (yellow, brown, or white), subungual hyperkeratosis, nail fragility, and separation of the nail from the nail bed (onycholysis). Involvement of the nail matrix can lead to regrowth that is misshapen or discolored for extended periods. Many cases are asymptomatic or only mildly symptomatic in the early stages.

Diagnosis relies on clinical examination supported by laboratory testing. KOH preparation of nail debris can reveal fungal elements, while fungal culture or molecular methods (PCR) can identify the causative species. Imaging is not routinely required but may be used to assess secondary bacterial infection or complications.

Treatment depends on severity and extent. Topical antifungals (such as efinaconazole or tavaborole) are used for mild, distal subungual cases, whereas systemic antifungals (terbinafine or itraconazole) are preferred for extensive or matrix-involved disease, often requiring several months of therapy. Treatment choices must consider potential side effects and drug interactions; liver function monitoring may be advised with systemic agents. Recurrence is common, so prevention and nail hygiene are important.

Prevention focuses on keeping nails dry and clean, avoiding trauma, treating athlete’s foot, and minimizing sharing of nail tools.