What should you know about yellow nail fungus?

Fungal nail infection can make a nail yellow, white or brown, thicker and more crumbly. It may begin at the edge and extend beneath the nail, sometimes with debris or an unpleasant smell. Athlete's foot can occur alongside nail fungus because the same type of infection may involve nearby skin.

A nail injury, psoriasis, eczema, repeated moisture or some medicines can also change nail colour and shape. A clinician may inspect the nail and take a clipping or scraping before choosing treatment, particularly when the appearance is unusual or several nails are involved. See Nail Fungus and Discoloured Nails for related information.

Keep feet clean and dry, change damp socks, wear well-fitting breathable footwear and avoid sharing nail tools. Trim nails straight across without digging into the corners, and do not pull off a loose nail. Treat athlete's foot if present and clean tools after use.

Treatment depends on how much of the nail is involved, how many nails are affected and your general health. Options may include Topical Antifungal Treatment, Oral Antifungal Treatment or, in selected cases, Laser Treatment For Nail Fungus. Nail Surgery is reserved for particular problems and is not needed for every discoloured nail.

Arrange a medical review for a new yellow streak, rapid change, pain, swelling, pus, bleeding, a dark area that reaches the surrounding skin, or a nail that lifts without a clear injury. Seek earlier advice if you have diabetes, poor circulation, reduced immunity or difficulty caring for your feet. A painful infected finger or toe may need prompt treatment.

Ask whether testing is needed, whether the nail changes fit fungus or another condition, which treatment suits your health and other medicines, how long nail growth may take, and how recurrence can be reduced.