Black toenail
What is black toenail?
Black toenail, also called runner's toe or tennis toe, is an injury that causes your toe to become blackened under the toenail.
It happens after doing exercise that puts pressure on your feet. Wearing shoes that are too tight, or stopping suddenly are common causes.
Symptoms
The key symptom of black toenail is a black or dark red area under a toenail, usually on the first or second toe. It will also feel hot and painful, especially under pressure.
As it heals, the toenail may loosen and drop off.
Causes
Black toenail is caused by bleeding underneath the toenail. This can be due to several things.
- An injury, for example your toe being crushed.
- Poorly fitting shoes or trainers, especially when they are too tight around the toes.
- Downhill running.
- Overly long, or misshapen toenails.
Treatments
Black toenail will heal slowly without treatment. After a few days the pain will begin to subside. You will be able to run and play sports again.
If it is very painful, you may need to have a procedure to release the blood building up under the toenail. A heated needle is used to puncture the nail and let the blood escape. A doctor will be able to do this.
Do
- Keep your toenails trimmed.
- Make sure you get shoes that fit properly, especially ensuring there is enough room at the toe box.
- Consider altering your running route to change the pressure on your feet.
- Wear socks, if you don't.
Don't
- Just ignore black toenail. Change your shoes to stop it happening again.
Peer reviewed by Alex Floyd, MCSP, Bupa Sports Medicine physiotherapist
Publication date: June 2009
