What should you know about nail bed fungus?

The infection can begin at the edge of a nail and extend beneath the nail plate. The nail may become yellow, white, brown, thick, brittle, ridged, or separated from the nail bed. Athlete’s foot can spread to the nails, but psoriasis, injury, and other nail disorders can look similar. A clinician may inspect the nail and test clippings or scrapings before recommending medicine.

Keep feet clean and dry, change damp socks, wear breathable footwear, and avoid sharing nail tools. Trim nails carefully and do not dig under them. Treatment depends on how many nails are involved, how deeply the infection extends, and your health history. Options include topical antifungal treatment, oral antifungal treatment, and selected laser procedures; nail surgery is reserved for particular situations. Improvement follows new nail growth, so follow the plan consistently.

Arrange a medical review for a painful, draining, rapidly changing, or badly damaged nail, or when several nails are affected. Seek earlier advice if you have diabetes, poor circulation, reduced sensation, or a weakened immune system. Urgent care is appropriate for spreading redness, severe swelling, fever, or a wound that will not heal.

Could this be fungus or another nail condition? Do I need a nail sample? Which treatment fits my health history? How should I protect other nails and household members? What changes should prompt a follow-up visit?