Discoloured Toe Nails: Possible Causes

A yellow, thickened, brittle nail with debris beneath it can occur with nail fungus, while pitting or separation may occur with nail psoriasis. A dark area after pressure or impact may be trapped blood that grows out with the nail. One nail changing in a sharply defined band, especially without an injury, should be examined rather than covered with polish. Discolouration can also come from footwear pressure, chemicals, or pigment trapped in the nail.

Keep feet clean and dry, change damp socks, and use roomy footwear. Do not share nail tools, and disinfect tools used on affected nails. Avoid scraping under the nail or starting an antifungal medicine before the diagnosis is clear; a clinician may examine nail clippings or other material. If fungus is confirmed, treatment may involve a topical option or Oral Antifungal Treatment, depending on the nail and your health.

Book an appointment for a new dark streak, colour change that is enlarging, a nail that becomes painful or lifts, or redness and drainage around it. Seek earlier care if diabetes, reduced circulation, nerve problems, or immune suppression makes foot problems harder to notice or heal. A nail that does not grow out as expected also deserves review.

Ask whether the pattern fits Nail Fungus, Nail Psoriasis, injury, or staining; whether testing is needed; how long the nail may take to look normal; and which treatment is safest with your medicines and medical history.