What is a common symptom of a nail fungal infection?

Discoloration of the nail is a common symptom of a nail fungal infection, as fungi can affect the nail and the area around it, leading to changes in color. Typically, the infected nail may appear yellow, brown, or even green, depending on the type of fungus causing the infection. This change in color results from the growth of the fungus beneath the nail and is one of the most noticeable signs that a nail infection may be present.

While painful swelling, increased nail growth, and rough texture can occur with various nail conditions, they are not specific indicators of fungal infections. Painful swelling is more commonly associated with bacterial infections or injuries. Increased nail growth may occur in certain circumstances, but it is not a typical symptom of fungal infections. A rough texture can be present in a variety of nail-related issues but does not exclusively indicate a fungal infection. Therefore, discoloration of the nail serves as a key symptom of a nail fungal infection, making it the correct identification in this scenario.