Toenail fungus is an infection that is caused by fungi that get through a crack in the nail or a small cut in the skin. It can make the nail thicker and change in color, turning it yellow, green, or brown. This nail infection may also hurt. Toes are often damp and warm. This is why fungus grows well in them too. Various types of fungi can cause this infection. Sometimes yeasts also cause it. The nail fungal infection may spread to other nails, the skin, or even other body parts.
Infected nails often appear thicker. They may also become thicker or oddly shaped. These nails can easily break. Nails that are infected with fungus turn yellow. Sometimes a white dot suddenly appears and becomes bigger over time. The nail may be loosened and separate from the nail bed.