Fungal Infection of a Nail (Onychomycosis)

What is onychomycosis?

Onychomycosis, also called tinea unguium, is a fungal infection of the fingernail or toenail.

How does it occur?

The fungus that causes this infection usually spreads from infected skin close to the nail.

What are the symptoms?

Infected nails are thickened and yellow or brown. They are more brittle than uninfected nails. They may crumble or flake.

How is it diagnosed?

Your health care provider will examine the nail. Your provider may take a scraping of the nail and look at it under a microscope for evidence of fungal infection. A sample of the nail may be sent to the lab for tests.

How is it treated?

If the infection is very mild, your provider may prescribe medicine you can put on the nail. For more severe infections, your provider may prescribe an antifungal medicine to be taken by mouth.

How long will the effects last?

You may need to take the medicine until the nail grows all the way out and there is no longer any sign of the fungal infection. This usually takes about 6 months for fingernails and 12 months for toenails.

How can I help prevent onychomycosis?

Fungi grow where it is wet. To keep fungal infections from occurring or to keep them from coming back once they have been treated, it's important to keep your hands and feet as dry as possible. It may help to:

• Put an antiperspirant medicine on your feet to prevent sweating.
• Change your socks often.
• Wear shoes that breathe well.
• Avoid going barefoot in public places where you might be exposed to a fungus, such as shower stalls at the gym. Wear shower shoes and clean them often.