What are the typical symptoms of tinea unguium?

Tinea unguium, also known as onychomycosis, primarily affects the nails and is characterized by specific nail-related symptoms. The symptoms typically include nail thickening and separation of the affected nail from the nail bed, which can lead to changes in the color and texture of the nail. This condition is commonly caused by fungal infections that invade the keratin in the nail, resulting in these noticeable alterations.

The other choices describe symptoms associated with different dermatological conditions. For instance, red-brown scaling with a snakelike border is indicative of tinea corporis or ringworm, which affects the skin rather than the nails. Itching in the groin area is characteristic of tinea cruris, commonly known as jock itch, and relates specifically to fungal infections in the groin. Painless bald patches on the scalp are symptoms of tinea capitis, another type of fungal infection, which involves the skin of the scalp rather than the nails. Thus, the correct choice highlights the symptoms that are specifically associated with tinea unguium and distinguishes it from other types of fungal infections.