Many people develop a fungal nail infection at some point in their life. It's not usually serious, but can be unpleasant and difficult to treat.
The infection develops slowly and causes the nail to become discoloured, thickened and distorted.
Toenails are more frequently affected than the fingernails.
The medical name for a fungal nail infection is onychomycosis.
Signs and symptoms of a fungal nail infection
A fungal nail infection may not cause any obvious symptoms at first.
As it progresses, the infection can cause:
discolouration of the nail – it may turn white, black, yellow or green
thickening and distortion of the nail – it may become an unusual shape or texture and be difficult to trim
pain or discomfort – particularly when using or placing pressure on the affected toe or finger
brittle or crumbly nails – pieces may break off and come away completely
Sometimes the skin nearby may also become:
What causes a fungal nail infection
Most fungal nail infections occur as a result of the fungi that cause athlete's foot infecting the nails.
These fungi often live harmlessly on your skin, but they can sometimes multiply and lead to infections. The fungi prefer warm, dark and moist places like the feet.
You're more likely to get a fungal nail infection if you:
don't keep your feet clean and dry
wear shoes that cause your feet to get hot and sweaty
walk around barefoot in places where fungal infections can spread easily, like communal showers, locker rooms and gyms
have damaged your nails
have a weakened immune system
have certain other health conditions, like diabetes, psoriasis or peripheral arterial disease
Fungal nail infections can be spread to other people, so you should take steps to avoid this if you have an infection.
Speak to your GP or pharmacist if:
you're bothered by the appearance of a nail with a fungal nail infection
the fungal nail infection is causing problems like pain or discomfort
Treating a fungal nail infection
A fungal nail infection is unlikely to get better without treatment. However, if you're not bothered by it you might decide it's not worth treating because treatment:
can take a long time
can cause side effects
isn't always effective
Treatment may also be unnecessary in mild cases of fungal nail infection. It's also unlikely to cause any further problems so you may feel it's not worth treating.
For more severe or troublesome fungal nail infections, antifungal medication may be recommended.
Antifungal medication comes in tablets or a special paint you apply directly to the nail.
A small sample of the infected nail may need to be taken and sent off for testing before treatment starts, to confirm that you do have a fungal infection.
If the treatment is working, you should see a new healthy nail start to grow from the base of nail over the course of a few months. The old infected nail should begin to grow out and can be gradually clipped away.
Antifungal treatments are thought to be effective in treating about 60 to 80% of fungal nail infections. It can take between 6 and 18 months for the appearance of the affected nail to return to normal, and in some cases the nail may not look the same as before the infection.
Terbinafine and itraconazole are the 2 medicines most commonly prescribed for fungal nail infections.
These usually need to be taken once or twice a day for several months to ensure the infection has completely cleared up. If you stop taking the medication too early, the infection may return.
Possible side effects of antifungal tablets can include:
If you prefer not to take antifungal tablets, your GP or pharmacist may suggest you try antifungal nail paint instead.
Nail paint isn't generally considered to be as effective as tablets because it can be difficult for it to reach the deeper layers of the nail. However, it doesn't usually cause any side effects.
Like antifungal tablets, antifungal nail paint also normally needs to be used for several months to ensure that the infection has cleared up.
Speak to your GP if new, healthy nail doesn't start to grow after a few weeks of treatment.
Keep using the treatment until your GP says you can stop. Stopping too early could result in the infection returning.
Softening and scraping away the nail
As it can take a long time for antifungal medication to work, some people may prefer to use a treatment that involves softening and removing infected parts of nail over a few weeks.
Treatment kits are available from pharmacies that contain a 40% urea paste, plasters and a scraping device. The paste softens the infected parts of the nail, allowing them to be scraped away so they can be gradually replaced with healthy nail.
To use the treatment:
wash the affected area and dry it thoroughly
carefully apply the paste to the infected nails
cover the nails with plasters and leave them for 24 hours
wash the paste off the next day and scrape away the softened parts of the nail
repeat this process each day for 2 to 3 weeks
Once no more infected parts of the nail can be removed, ask your pharmacist for antifungal nail paint to prevent re-infection as the nail regrows over the next few months.
Removing the nail
A procedure to remove affected nails completely isn't usually necessary, but may be recommended if the infection is severe or painful and other treatments haven't helped.
If your nail is surgically removed, a new nail should eventually grow back in its place. However, it could take a year or more for the nail to grow back completely.
Laser treatment is a possible option if you have a fungal nail infection that's particularly stubborn. The laser emits high doses of light energy, which are used to destroy the fungus.
Early research suggests the treatment may be helpful in treating fungal nail infections, but there's currently not enough evidence to recommend it as a routine treatment.
If you want to try laser treatment, you'll have to pay for it privately because it's not available on the NHS. Be aware that the treatment may need to be repeated several times for up to a year, so it could get very expensive.
How to prevent fungal nail infections
Whether or not you decide to have treatment, you should still follow self-help advice to help stop the condition getting worse or spreading to others.
keep your hands and feet clean and dry
wear well-fitting shoes made of natural materials and clean cotton socks – these will allow your feet to "breathe"
clip your nails to keep them short – don't share clippers or scissors with other people
replace old footwear that could be contaminated with fungi
treat athlete's foot as soon as possible to avoid the infection spreading to your nails
ensure your towels are washed regularly
make sure any equipment is properly sterilised between uses if you visit a nail salon
do not share towels and socks with other people
do not walk around barefoot in public pools, showers, and locker rooms – special shower shoes are available to protect your feet