What term describes an infection that affects the nail?

The correct term that describes an infection affecting the nail is paronychia. This condition specifically involves the tissue surrounding the nail and occurs when bacteria or fungi infect this area, leading to symptoms such as redness, swelling, and pain.

Onychomycosis refers to a fungal infection that affects the nail bed and can lead to changes in nail appearance and structure. While onychomycosis is important in understanding nail health, it specifically indicates a fungal issue rather than a general infection.

Onycholysis is the separation of the nail from the nail bed, which can be caused by various factors but is not an infection in itself. Instead, it often appears due to trauma, allergic reactions, or other non-infectious causes.

Onychosis is a broader term that refers to any disease of the nail, without specifying whether it's an infection or an underlying condition. This term encompasses various nail disorders but does not specifically denote an infection.

In summary, paronychia precisely describes an infection related to the surrounding tissue of the nail, making it the most accurate term for this scenario.