What should you know about finger nail fungus?

The nail may turn white, yellow, or brown, develop ridges, become difficult to trim, or collect debris beneath its edge. It often changes gradually and may affect one nail or several. A damaged nail, eczema, psoriasis, or repeated wet exposure can look similar, so appearance alone cannot confirm fungus. Fungal infection can also travel between skin and nails; athlete’s foot may be present at the same time. See [Nail Fungus](/conditions/nail-fungus/) and [Discoloured Nails](/symptoms/nail-discoloration/) for related information.

Keep the nail short and dry, wash your hands, and avoid sharing nail tools or towels. Do not scrape under the nail or cover a changing nail with polish for long periods. A clinician may examine the nail and take a small clipping or scraping before choosing treatment. Options can include [Topical Antifungal Treatment](/treatments/medical-dermatology/topical-antifungal-therapy/) for selected infections or [Oral Antifungal Treatment](/treatments/medical-dermatology/oral-antifungal-therapy/) when medicine needs to reach the nail through the bloodstream. [Laser Treatment For Nail Fungus](/treatments/laser-and-energy/laser-nail-fungus-treatment/) and [Nail Surgery](/treatments/surgical-dermatology/nail-surgery/) may be discussed in particular situations.

Arrange an assessment if the nail is painful, increasingly swollen, draining, rapidly changing, or lifting after an injury. Seek prompt care for spreading redness, warmth, or pus, especially if you have diabetes, poor circulation, or a weakened immune system. A dark streak that is new, widening, irregular, or extending onto the surrounding skin needs dermatology review because not every nail change is fungal.

Ask whether a nail sample is needed, whether nearby skin or other nails should be checked, which treatment fits the extent of the change, and how to protect the nail while it grows out. Mention medicines, liver problems, allergies, pregnancy, and any earlier treatment that did not work.