When should you see a doctor about discoloured nails?

Yellow, white, brown, black, or green colour may reflect trauma, moisture-related infection, inflammation, or pigment in the nail or surrounding skin. Green Nail Syndrome and Nail Fungus can alter colour and texture; Nail Psoriasis can cause pitting or separation. A dark band or spot may be Melanonychia, while blood beneath a nail after an impact can be a Bruised Nail. Colour alone cannot distinguish these causes.

Keep nails clean and dry, avoid picking or scraping beneath them, and pause polish or artificial nails so the surface can be examined. Do not share clippers or files. Note when the colour appeared, whether it is moving as the nail grows, any injury, and changes in thickness, lifting, smell, tenderness, or discharge. Do not start an antifungal medicine without confirming the cause.

Book an appointment for a persistent unexplained colour change, a dark streak that is widening or reaching the surrounding skin, a nail that lifts, or pain, swelling, bleeding, or discharge. Seek prompt care after a significant injury if pain is severe or the nail is markedly damaged. A clinician may inspect the nail, sample material, or discuss Oral Antifungal Treatment when appropriate.

Ask whether the change is growing out with the nail, whether testing is needed, how to protect nearby nails, and which signs would require earlier review.