Toenail fungus is a condition that disfigures and sometimes destroys the nail. It is also called onychomycosis
Toenail fungus can be caused by several different types of fungi. Fungi are microscopic organisms related to mold and mildew.
These fungi thrive in the dark, moist and stuffy environment inside shoes. As they grow, fungi feed on keratin. Keratin is the protein that makes up the hard surface of the toenails.
Factors that increase the risk of developing toenail fungus include:
Wearing tight-fitting shoes or tight hosiery
Practicing poor foot hygiene
Wearing layers of toenail polish, which doesn't allow the nail to breathe
Being a military personnel, athlete or miner. This is because toenail fungi may spread from foot to foot on the floors of showers and locker rooms.
Having a chronic illnesses, such as diabetes or HIV
Having a circulatory problem that decreases blood flow to the toes
However, many people with toenail fungus have no clear risk factors.
Toenails on the big toe and little toe are the most likely to develop a toenail fungus. This may be partly because the big toe and little toe are constantly exposed to friction from the sides of shoes.
To continue reading this article, you must login
Subscribe to Harvard Health Online for immediate access to health news and information from Harvard Medical School.