Onychoptosis is the medical term for a toenail falling off. This term comes from Greek origins and literally means "Nail falling off". There are two reasons why a toenail may fall off: Injury and Fungus. Nail fungus is called onychomycosis, and usually occurs when fungus enters the nail area through a small cut or some other injury. There are various injuries that can cause a nail to fall off, stubbing a toe or jamming into a small area like a door are a couple of causes. A toenail falling off due to injury or fungus is not uncommon.
Look at the Toenail area.
A sign of injury can be bruising of the skin, or blood clotting beneath the toenail, which is called a subungual hematoma. If this occurs a physican may need to let the blood out. A subungual hematoma is a painful bleeding under the nail and is not to be confused with a bruised nail, which is not as painful.
A symptom of fungs is the nail turning yellow, white or brown. The nail may also become thick and brittle.
Clean the area well with soap and lukewarm water.
Keep it dry
Apply an antisceptic (benzalkonium chloride) to the area once or twice daily. The new nail should grow in within a couple of months.
If the nail does not grow in, consult a podiatrist (foot doctor). The doctor may prescribe a topical ointment to treat a fungal infection, or she may give you an oral medication to kill the infection. In some rare cases surgery (removal of the nail or infected area) may be necessary.
In most cases a toenail falling off due to injury will grow back on its own over a period of months. During the regrowth process, try not to put pressure on the injured area.
Avoid wearing pointy-toed shoes, or high heels.
Keep feet dry
If your nail does not grow back, or is growing back in a way that is painful or unsightly, consult a doctor.