The foot thumb nail is empty, mostly considered to be physiological factors, such as nail malnutrition, as well as pathological factors, such as onychomycosis or external impact and other reasons. 1. Nail malnutrition: when the nail plate in the formation process, was affected, can change the nail plate texture, structure, shape and color, can lead to toe nail empty. 2. Ringworm of the nail: when the hands or feet for a long time by the fungal infection, can gradually involve the nails, triggering ringworm of the nail. In the long run, it will cause under-nail debris, thickening and clouding of nails, and when a large amount of nail debris accumulates, it can cause the nail plate to be lifted up to a certain extent, making the under-nail cover become empty. 3. Nails were hit by external forces: when the nails were hit by external forces, initially the nails and the nail bed connection is good, the nails may only show pain or bleeding, but with the growth of the nails, it is slowly detached from the nail bed, from the appearance of the empty state. There may also be other reasons for an empty thumbnail, such as prolonged immersion of the feet in irritating chemicals, which can also cause this symptom over a long period of time. It is recommended that the patient be admitted to the hospital as soon as possible, complete the examination, clarify the cause of the disease and then give targeted treatment or treatment under the guidance of the doctor.