Which term describes a fungal infection of the nail characterized by thickening, discoloration, and lifting from the nail bed?

• A. Tinea pedis/athlete's foot
• B. Bunion/hallux valgus
• C. Onychomycosis/tinea unguium/nail fungus
• D. Hammertoe

Answer: (C)

Onychomycosis, also called tinea unguium, is the term for a fungal infection of the nail. The nail becomes thickened, discolored, and can lift away from the nail bed (onycholysis), which are classic signs of fungal invasion of the nail unit. This is different from tinea pedis, which affects the skin of the foot rather than the nail, and from bunion (hallux valgus) or hammertoe, which are toe deformities rather than infections. Onychomycosis is commonly caused by dermatophytes such as Trichophyton species, and recognizing this nail-specific infection helps guide appropriate treatment.