Causes of empty toenails include nail dystrophy, onychomycosis, gray toenails, etc. 1. Nail dystrophy: when the toenail is exposed to acidic solutions and irritating detergents for a long period of time, the structure and function of the nail matrix can be damaged, inducing nail dystrophy. This leads to changes in the shape, color, and texture of the nail plate, resulting in an empty toenail. 2. Nail fungus: when the body resistance is low or neglect foot hygiene, it is easy to be infected by fungi, so that the nail plate and sub-nail tissues are infringed upon, thus inducing an inflammatory reaction of the tissues, leading to nail fungus. It makes the nail plate appear cloudy, thickened and discolored. When the subnail tissue is infected too deeply, it will lead to the occurrence of empty toenails. 3. Gray nails: Nail lesions caused by fungal infections. The nail bed is damaged and missing, causing white powdery substances to appear in the toenail. At this time, you should actively carry out antifungal treatment. It is recommended to pay attention to foot hygiene and keep the feet dry and clean. If the symptoms are serious, it is recommended to go to a regular hospital for timely treatment to avoid delaying the condition.