What is a common sign of nail fungal infections?

Thickening of the nail is a common sign of nail fungal infections because the infection leads to changes in the nail's structure. When a fungal infection occurs, it often affects the nail bed and may cause the nail to grow more slowly, resulting in increased thickness. This occurs as the fungus disrupts the normal process of nail growth, leading to more layers of keratin being produced and ultimately creating a thickened appearance.

In contrast, bright red color is typically associated with inflammation or some form of injury rather than a fungal infection. White spots can be indicative of a variety of issues, not exclusively fungal infections, and may often result from trauma. Nail splitting is usually related to factors like dryness or mechanical stress rather than being a direct symptom of a fungal infection. Therefore, the thickening of the nail serves as a key indicator of a fungal infection, helping to differentiate it from other conditions affecting the nails.