Nail fungal infections are typically caused by a dermatophyte fungus. Yeasts and molds also can be responsible for nail fungal infections.

What are fungi?

Fungi are microscopic organisms that don't need sunlight to survive. Some fungi have beneficial uses. Others cause illness and infection. Fungi:

  • Live in warm, moist environments, including swimming pools and showers
  • Can invade your skin through cuts so tiny you can't even see them or through a small separation between your nail and nail bed
  • Can cause problems if your nails are often exposed to warm and moist conditions

Toenails vs. fingernails

Nail fungus occurs more often in toenails than in fingernails, partly because:

  • Toenails often are confined in a dark, warm, moist environment — inside your shoes — where fungi can thrive
  • Toes usually have less blood flow than do fingers, making it harder for your body's immune system to detect and stop infection
Jul. 26, 2014

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