Definition of Onychomycosis

OnychomycosisA common fungal infection, typically candidiasis or tinea, of the fingernail or toenail.

The infection causes the nail to thicken, discolor, fragment, and peel or crack.

Though some people experience itching, pain, or other discomfort, most people seek medical care because of the nail’s appearance. Onychomycosis affects the structure and function of the nail, however.

Onychomycosis affecting multiple toenails can interfere with proper walking, and onychomycosis of the fingernails may reduce gripping ability and the ability to perform tasks such as typing or keyboarding.

The doctor often can make the diagnosis based on the appearance of the nails, though may choose to examine tissue samples under the microscope to confirm the presence of the infective fungus.


Eradication of the fungus often requires oral antifungal medication in combination with topical antifungal medication. Onychomycosis can be a stubborn infection, making several courses of treatment necessary.

Early diagnosis and treatment affords the most successful results.


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