If you have a fungal nail infection, the whole nail may be affected or only a smaller area. Several nails can be affected at once or just one nail. The easiest physical signs of a fungal nail infection to spot are discoloration. The top of the nail will become noticeably more dull and lack in its natural shine. Often the nail will turn to a dark green-ish or dark yellow-ish hue. This is caused by debris and fungus building up under the nail.
If you have a nail that is infected, it may be painless at first. However, these infections can cause nails to split, break, and rise up from the nail bed, sometimes causing pain underneath it.
The nail will often become brittle, causing it to crumble or become ragged. Because of these symptoms, the natural shape of the nail can also become distorted and change.