If one of your toenails or fingernails is thick and white, or if it crumbles when you touch it, you probably have a fungal infection. It may look bad, but it's not serious. And treatment can help.
We've brought together the best research about fungal nail infections and weighed up the evidence about how to treat them. You can use our information to talk to your doctor and decide which treatments are best for you.
If one of your nails is thick and looks white or yellow, or if it crumbles when you touch it, you probably have what doctors call a fungal infection. It may look bad, but it's not serious. Treatments can stop it hurting and help clear up the infection.
It's easy to catch a fungal nail infection, especially in a toenail. But the sooner you treat it, the easier it is to get rid of the infection.
This condition is sometimes called tinea or ringworm. But it's not caused by a worm.
Key points for people with fungal nail infections
Fungal infections of your nails don't usually cause serious problems.
If you don't get treatment for an infected nail, it can spread to other nails.
Serious infections can damage your nail. This can make it hard to walk.
You don't need to be embarrassed about having a fungal nail infection, no matter how horrible you think it looks. Doctors are used to seeing them.
Fungal nail infections can be cured.
You can buy some treatments over the counter. Or your doctor can prescribe others if you need them.
It might take up to one year to get rid of an infection if it's bad.
What causes it?
You may not like the idea of a fungus living on your skin. But the fungi that grow under your nails are tiny organisms, like bacteria or a virus. The fungus is so small that you can't see it.
The type of fungus that gets under your nails lives only on top of your skin. It doesn't go inside your body. This condition is sometimescalled ringworm, but it's not caused by a worm.
You can't see the tiny fungi that cause these infections. They live in warm, damp places, such as showers, and floors around swimming pools and in changing rooms.
There are lots of things you can do to avoid getting another nail infection. For example, you can wear flip-flops when you use changing rooms at the swimming pool. See How to avoid getting a fungal nail infection for more tips.
Fungal infections often affect the nail on your big toe. If you don't treat the infection, it can spread to other nails on your toes and to your fingernails.
A condition called athlete's foot is also caused by a fungus. It's an itchy infection of the skin on and between your toes, but it can spread to your nails.