A black toenail, also called Subungual Hematoma or jogger’s toe is a common sports injury. It is caused either suddenly by direct trauma, or gradually through repetitive rubbing inside shoes.
Medically reviewed by Dr Chaminda Goonetilleke, 20th Jan. 2022
Black toenail symptoms
- Your toenail appears black.
- Your toe may feel like it is throbbing.
- Eventually, your nail may loosen from the nail bed and eventually fall off.
What causes a black toenail?
If you have suffered a black toenail then it is likely you have either stubbed your toe, dropped something on it, or run a very long way. Trauma causes soft tissue injury resulting in bleeding under the nail. As a result, the nail appears black.
Blood has nowhere to drain to, therefore pressure under your nail increases causing pain. You may feel a throbbing sensation. This is because as your heart beats (creating a pulse) your blood pressure varies, hence the pressure in your toe increases.
Black toenails are common in long-distance runners and soldiers who undertake long-distance marches in boots.
Treatment for a black toenail
Black toenails usually heal by themselves, but if they are particularly painful or severe, further treatment may be necessary.
Trephining is the process of making a hole in your nail to release pressure by draining blood from under the nail.
A professional therapist or chiropodist may use something about the size of a paperclip to pass easily through the nail. As a result, a tiny hole is made through the nail. If pressure under your nail is high enough blood may briefly spurt out.
The nail is then covered with a small dressing to prevent infection. Once pressure under the nail is released, it should no longer be as painful.
- Nail removal is used in more extreme cases where the nail becomes misshaped or disrupted by the hematoma (swelling).
- Or if there is a more serious underlying injury such as a fracture of your toe.
- Anaesthetic is not usually used, but sometimes nerve blocks are used.
Subungual Hematomas usually heal by themselves with little incident other than the pain but can become infected or disrupt the nail.