What is toenail fungus?

Toenail fungus is a widespread fungal infection that affects the toenails. Less commonly, nail fungus infects the fingernails. Nail fungus is also called onychomycosis.

Toenail fungus happens when fungi get between the toenail and the toenail bed (tissue right underneath the toenail). This usually happens through a crack or cut in your toe.

How common is toenail fungus?

Toenail fungus is very common, especially as people get older. Medical experts estimate that onychomycosis affects 1 in 10 people overall. That number jumps to 1 in 2 (50%) for people older than 70.

What causes toenail fungus?

More than one type of fungi can affect the toenails. Dermatophytes (a type of mold) cause most toenail fungal infections.

Dermatophytes are fungal microorganisms (too tiny to see with the naked eye). They feed off of keratin, a protein found in your fingernails and toenails. Keratin makes nails hard.

Is toenail fungus contagious?

Yes, many types of toenail fungi are quite contagious. An infected person can spread the fungus to someone else through direct contact. You can also get toenail fungus by touching an infected surface.

What are common ways you can get toenail fungus?

Nail fungi like warm, moist, dark places. Many people get toenail fungus by:

  • Walking around the perimeters of swimming pools.
  • Using a public locker room or shower.
  • Walking barefoot in a public area.

Can toenail fungus spread to other areas of the body?

Yes. But toenail fungus usually doesn’t spread beyond the toe.

Some dermatophyte fungi spread easily to the skin. (Your skin and scalp also contain keratin.) When dermatophyte fungi affect the skin, it’s called ringworm.

Toenail fungus may spread to:

  • Other toenails.
  • Skin between your toes (called athlete’s foot).
  • Groin area (called jock itch).
  • Scalp (skin on top of your head).

Who is likely to get toenail fungus?

Anyone can get toenail fungus. It often affects older adults, especially people over 60.

You may have a higher risk of getting toenail fungus if you have:

What does toenail fungus look like?

Toenail fungus can change your toenail’s appearance in more than one way. Your toenail may:

  • Change color, looking white, yellow or brown.
  • Look chalky or cloudy in some spots.
  • Thicken and possibly look misshapen.
  • Separate from the nail bed (leaving space between the nail and the skin underneath).
  • Crack or break in one or more spots.

Is toenail fungus painful?

Not typically. Toenail fungus can be unsightly to look at, but it usually isn’t painful.

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