Nail fungus

Nail fungus is a common condition that begins as a white or yellow spot under the tip of your fingernail or toenail. As the fungal infection goes deeper, nail fungus may cause your nail to discolor, thicken and crumble at the edge. It can affect several nails but usually not all of them.

If your condition is mild and not bothering you, you may not need treatment. If your nail fungus is painful and has caused thickened nails, self-care steps and medications may help. But even if treatment is successful, nail fungus often comes back.

Nail fungus is also called onychomycosis (on-ih-koh-my-KOH-sis) and tinea unguium. When fungus infects the areas between your toes and the skin of your feet, it's called athlete's foot (tinea pedis).

Symptoms Causes Risk factors Complications Prevention

You may have nail fungus — also called onychomycosis (on-ih-koh-my-KOH-sis) — if one or more of your nails are:

  • Thickened
  • Brittle, crumbly or ragged
  • Distorted in shape
  • Dull, with no shine
  • A dark color, caused by debris building up under your nail

Infected nails also may separate from the nail bed, a condition called onycholysis (on-ih-KOL-ih-sis). You may feel pain in your toes or fingertips and detect a slightly foul odor.

When to see a doctor

You may want to see a physician if self-care steps haven't helped. Also see a doctor if you have diabetes and think you're developing nail fungus.

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