Introduction 

A fungal nail infection affects the hard material (keratin) that makes up the nails.

Fungal nail infections can affect part or all of the nail, including the nail plate, nail bed and root of the nail.

The infection develops slowly and causes the nail to become discoloured, thickened and distorted. The toenails are more frequently affected than the fingernails.

Onychomycosis is the medical name for a fungal nail infection.

Read more about other nail abnormalities.

Signs and symptoms of a fungal nail infection

The most common sign of a fungal nail infection is the nail becoming thickened and discoloured. The nail can turn white, black, yellow or green.

You'll not usually feel any pain at first, but the nail can look ugly. In most cases, a fungal nail infection won't cause any further complications. However, it may cause pain and discomfort if the infection isn't treated, although this is rare.

Read more about the signs and symptoms of a fungal nail infection.

What causes a fungal nail infection?

Most fungal nail infections are caused by dermatophyte fungi, which also cause athlete's foot.

Athlete's foot is a fungal skin infection that affects the skin between the toes. It can easily spread to the toenails.

Ocassionally, a nail infection can be caused by other types of fungi, such as Candida (a yeast that causes infections such as vaginal thrush).

Several factors increase the risk of a fungal nail infection developing. For example:

  • wearing shoes that cause your feet to get hot and sweaty
  • being in a humid environment
  • regular damage to the nail or skin
  • poor health or certain health conditions, such as diabetes or psoriasis

Read more about the causes of a fungal nail infection.

Treating a fungal nail infection

Treatment isn't always needed for mild fungal nail infections. Your GP may send a clipping of your nail for laboratory testing to discover the exact cause of the infection and rule out other conditions. They'll then discuss appropriate treatments with you.

Fungal nail infections can be treated and usually cured, but some treatments can take several months to work. Antifungal medicines include antifungal tablets and nail paint.

Antifungal tablets are usually effective, but they may cause side effects. You should discuss this with your GP before deciding which treatment to use.

Surgery to remove the nail may be recommended in very severe or painful cases. Laser treatment, where a high energy laser is used to destroy the fungus, is also an option. However, this is expensive and is only available privately.

During and after treatment it's important to look after your nails properly and practise good foot hygiene to stop the infection returning.

Read more about treating a fungal nail infection.

Who gets fungal nail infections?

Fungal nail infections mainly affect older adults. They are rare in children.

People with certain health conditions have an increased risk of developing a fungal nail infection. These include:

  • fungal skin infections, such as athlete's foot
  • psoriasis, a skin condition that causes red, flaky and crusty patches of skin covered with silvery scales
  • diabetes
  • peripheral vascular disease

Nail infections are also more common in people with lowered immune systems.

Read more about who's at risk of developing a fungal nail infection.

Page last reviewed: 10/01/2014

Next review due: 10/01/2016