Tinea unguium, also known as onychomycosis, is a common fungal infection of the nails, especially the toenails. It thrives in warm, moist environments like shoes and socks. The infection often causes nails to thicken, discolor (turning white, yellow, or brown), become brittle or crumbly, and sometimes separate from the nail bed.
The fungus responsible can come from dermatophytes, yeast, or molds. It's more likely to affect those who wear tight footwear, walk barefoot in damp communal areas (like pools or locker rooms), have a history of athlete’s foot, or have a weakened immune system or diabetes.
Treatment options include topical antifungal medications for mild cases and oral antifungal medications for more severe infections. Other treatments can involve trimming and thinning the nails, laser therapy, or even surgical removal in severe cases. To prevent tinea unguium, keep your feet clean and dry, wear breathable shoes and socks, avoid walking barefoot in communal areas, and don't share nail tools.