The most common symptom of a fungal nail infection is the nail becoming thickened and discoloured. The nail can turn white, black, yellow or green.
A fungal nail infection is usually painless at first and in most cases fungal nail infections will not cause any further complications. However, if the infection is left untreated it may cause pain and discomfort, but this is rare.
If there is pain in the toenail, this can eventually lead to difficulty wearing shoes and walking. In fingernails, it may cause difficulty writing.
As the infection progresses there can be further symptoms, such as the nail becoming brittle, with pieces of nail breaking off or even coming away from the toe or finger completely.
If left untreated, the skin can sometimes become inflamed and painful underneath and around the nail (the nailbed). There may also be white or yellow patches visible on the nailbed or scaly skin next to the nail.
Read more about how fungal nail infection is treated.
Complications of a fungal nail infection
In very rare cases the infection can spread to the skin around the nail, resulting in cellulitis (bacterial infection under the skin) or osteomyelitis (infection of the bone).
These complications are slightly more common among older people and people with health conditions such as diabetes.
