Causes of a fungal nail infection 

The most common causes of fungal nail infections are a fungal skin infection or damage to the nail or skin.

Athlete's foot

A fungal infection in the toenail is often caused by a fungal skin infection such as athlete's foot. About a third of people with athlete's foot also develop a nail infection. Athlete's foot usually affects the skin between your toes, causing it to become red, flaky and itchy.

Fungi grow and thrive easily in warm, damp environments, so an infection is more likely to occur after wearing trainers for long periods or if you often have hot, sweaty feet.

Other causes

Fingernail infections are most often caused by a yeast called candida, which causes infections such as vaginal thrush.

You're more likely to develop a fingernail infection if your job involves a lot of handwashing or your hands are in water for long periods of time. This is because the skin at the base of your nail can become damaged and is more likely to become infected.

Your risk of developing a fungal nail infection is also increased if you have certain health conditions or health issues, such as:

Other factors that can increase the risk of nail infections include:

  • using artificial (cosmetic) nails
  • nail damage
  • constant nail biting
  • living in a warm and humid climate
  • smoking

Nail infections are more likely to occur with increasing age. Sometimes there's no obvious cause for an infection.

Page last reviewed: 10/01/2014

Next review due: 10/01/2016