How can you identify a nail fungus?

Identifying a nail fungus involves observing several key characteristics of the affected nail. A noticeable indicator is that the nail may appear discolored, showcasing variations in color such as yellow, brown, or white, along with a thickened appearance. This change occurs as the fungus builds up, affecting both the nail's structure and its coloration.

The other options do not specifically correlate with fungal infections. While dry and cracked nails may suggest other conditions, they are not definitive signs of a fungal infection. Excessive shine on a nail typically indicates good health or polish application, but it doesn't relate to fungal issues. An unusual increase in nail growth can occur for various reasons, but it doesn't specifically point to the presence of a fungal infection. In contrast, the combination of discoloration and thickening is a clear sign of nail fungus, making this option the correct choice.