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by Shannon DW
(Tinea Unguium; Fungal Nail Infection)


Onychomycosis is an infection of the toenail or fingernails.

Fungal Infection of the Toenails
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The infection is caused by a fungus. It can spread to humans from direct contact. This type of fungus lives in warm, moist places such as showers.

Risk Factors

Things that increase the risk of onychomycosis include:


Onychomycosis may cause:

  • Thickened nail that is difficult to cut
  • Brittle or ragged nail
  • Discolored or unsightly nail
  • Pain in the nail with normal use

It may happen in one or more of the nails.


The doctor will ask about and past health. A physical exam will be done. A piece of the nail may be removed for testing. Results make take several weeks.


Onychomycosis can be hard to treat. It may return after treatment. Treatment options include:

  • Antifungal medicine—may be pills or creams and lotions applied to the area
  • Surgery—nail may need to be removed for severe infections

Nails grow slowly. It can take up to a year to clear the nail.


Steps that may lower the chance of onychomycosis:

  • Keep feet clean. Dry them completely after washing.
  • Keep hands dry. Wear rubber gloves when cleaning.
  • Keep nails short and clean. Trim them straight across.
  • Do not trim or pick at the skin near nails.
  • Do not wear shoes that are too tight.
  • Wear cotton socks that can pull moisture away from skin. Change socks if they are damp.
  • Use footwear when walking around swimming pools, locker rooms, and other public places.
  • Avoid artificial nails. They can trap moisture.


American Academy of Dermatology  https://www.aad.org 

Foot Health Facts—American College of Foot and Ankle Surgeons  https://www.foothealthfacts.org 


Canadian Podiatric Medical Association  http://www.podiatrycanada.org 

The College of Family Physicians of Canada  http://www.cfpc.ca 


Nandedkar-Thomas MA, Scher RK. An update on disorders of the nails. J Am Acad Dermatol. 2005;52(5):877-887.

Onychomycosis. EBSCO DynaMed Plus website. Available at:  https://www.dynamed.com/topics/dmp~AN~T115521/Onychomycosis  . Updated December 3, 2018. Accessed January 11, 2019.

Onychomycosis. Merck Profesional Manual. Available at: https://www.merckmanuals.com/professional/dermatologic-disorders/nail-disorders/onychomycosis. Updated November 2017. January 11, 2019.

Westerberg DP, Voyack MJ. Oonychomycosis: Current trends in diagnosis and treatment. Am Fam Physician. 2013;88(11):762-770.

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