It should be noted that not all antifungal treatments are suitable for all types of fungal infections.

Dark nail polish can certainly stain your nails and give them a yellowish shade.
The other main reason that can cause stains on your nails is the excessive use of your hands. When you use your hands, including your fingers, to do a lot of daily tasks, you put a lot of stress on your nails, which can damage the nail base.
A potential nutritional deficiency.

