Toenail loss may be caused by trauma, fungal infection, malnutrition and other reasons. 1. Trauma: it may be caused by localized external smashing and extrusion of the toes, which can make the bruise appear in the position of the nail bed, the toenail and the nail bed are separated, and the toenail will buckle up, and the toenail will appear the phenomenon of toenail detachment. 2. Fungal infection: due to fungal infection in the nail tissue of toenail, common fungi are non-skin fungus filamentous fungi, dermatophytes and so on. As the fungus can invade the inside of the toenail, which can make the toenail flaky peeling phenomenon. 3. Malnutrition: It may be caused by the lack of B vitamins, calcium and other nutrients. Since there is no nutrition to provide the normal metabolism of the patient’s body, dry skin, brittle hair, ascites and anemia can occur. In severe cases, the toenails may suffer from stunted growth and development, leading to loss. It is recommended that patients with detached toenails go to the hospital in time and follow the doctor’s instructions for treatment to avoid delays.