Onychomycosis (Nail Fungus)

Onychomycosis (Nail Fungus)

Patient Information


Onychomycosis, commonly known as fungal nail infections, can affect the fingernails or toenails. These infections can cause the nail to become discolored, thick, and brittle.


Common symptoms of nails with a fungal infection include:

    • White, yellow or brown discoloration
    • Thickening of the nail
    • Fragile or cracked
    • Nail separation from the nail bed

Fungal infections more frequently affect the toenails but can also occur on the fingernails. Often, this is painless unless it becomes severe. People who have fungal toenail infections may also develop athlete’s foot, an infection of the foot skin caused by the same fungus.


Fungal nail infections occur when certain types of fungi (yeasts or molds) enter the nail and skin through small cracks on the tissue surface. Anyone can get a fungal nail infection but older adults and those with the following conditions are more likely to become infected:

    • A nail injury or nail surgery
    • Diabetes
    • A weakened immune system
    • Blood circulation problems
    • Athlete’s foot (ringworm on the foot)


The following steps will help prevent the risk of getting a fungus infection:

    • Keep your hands and feet clean and dry.
    • Clip your fingernails and toenails short and keep them clean.
    • Avoid walking barefoot in areas like locker rooms or public showers.
    • Avoid sharing nail clippers with other people and verify licensed nail salon before visiting or bring your own equipment. 


Your doctor may diagnose a fungal nail infection by examining the affected nail and your symptoms. He or she may also take a sample of your nail to look at under a microscope or send to a laboratory for a fungal culture.


Fungal nail infections can be difficult to cure and do not go away on its own. The most common and effective treatment is oral antifungal medication. In more severe cases, your doctor may surgically remove the infected portion or the entire nail completely. It can take several months to a year for the infection to go away.



Centers of Disease Control and Prevention. (2017). Fungal nail infections. Retrieved from https://www.cdc.gov/fungal/nail-infections.html