Nail fungus does not usually go away by itself and complications may arise if left untreated. Nail fungus can be painful and cause permanent damage to nails. A common complication is a ingrown nail.

Nail fungus can create an abnormally shaped toenail that then becomes ingrown. An ingrown nail grows into the skin instead of over it. This usually happens to the big toe but it can also occur in others nails too. An ingrown toenail can become infected making it red, swollen and seeping pus. People with curved or thick nails are more likely to have an ingrown toenail and this is more common in older adults.