Black Spot Under The Toenail

A black spot under the toenail is usually caused by one of four common problems: Learn what to do below!

Black Spot Under The Toenail Causes:

There are four common causes that I have seen of a black spot under the big toenail, here they are listened in order from most common to least common:


1) Jogger’s Toe (Subungual Hematoma).


Jogger’s toe is essentially just “overuse toe”.

  • The trick with this one is it sneaks up on people without any pain!
  • Be aware that you can still have bleeding underneath your toenail and it doesn’t have to be extremely painful.
  • For example I just saw a woman had a scary black toenail without any cause.
  • But the more I talked to her I realized she bought new shoes and started Zumba classes.
  • She was exercising more, had small shoes and was not suffering from any pain!




  • Sometimes no pain.
  • Small shoes.
  • New shoes.
  • New exercise regimine.
  • Heavy running or work.
  • Traumatic injury.
  • Dropping something on your foot.
  • It will grow out over time.
  • It will not get bigger over time.



2) Subungual Melamona (Black Streak or Mole).

This is as a result of a mole!

  • These can appear underneath your toenail or around the toenail.
  • The first step is to keep an eye on these and see if they are getting bigger.
  • These can be dangerous, so if they are getting bigger or growing into the skin- go see a podiatrist or foot doctor immediately!




  • No Pain.
  • It is getting bigger.
  • It has been there a long time.
  • No cause for its appearance.
  • It may be growing into the tissue.
  • See our “Is it dangerous guide?



3) Pseudomonas Bacterial Infection.

This is different than toenail fungus- this is an bacterial infection.

  • This means it comes quick and strong, then gets cured for good once you see a podiatrist.
  • This goes against toenail fungus which is very slow and resistant.



  • Pseudomonas is a bacteria that loves oxygenated moist environments like wet mud and pond water.
  • If you have been around any of these recently and you start getting greenish-black toenails, it may be this!
  • You should go see your podiatrist or foot doctor for some antibiotics!
  • It can also be confirmed by it’s sweet smelling grape-like odor.


  • No Pain.
  • Greenish-black.
  • Appears quickly.
  • Sweet, grape-like odor.
  • History of swimming in pools or ponds.



4)Toenail Fungus Can Cause Black Streaks:

If the above does not sound like your situation, consider toenail fungus as well.

  • Toenail fungus is associated with 80% of all toenail problems.
  • It usually manifests as thick yellow toenails, but there can be brown and black marks as well.


Toenail Fungus Is Associated With 80% Of All Toenail Problems:


Symptoms of Toenail Fungus:

  • Thick yellow toenails.
  • Crumbling debris underneath the toenails.
  • Incurvated or possibly ingrown toenails.
  • Discoloration or streaking.

Click on this link to our comprehensive nail fungus home treatment guide. Always be sure to see a podiatrist if you are ever unsure!


  • Thick Toenails.
  • Yellowish-green.
  • Crumbling toenails.
  • Discolored.
  • Appear slowly and last forever.
  • No Pain.
  • Usually associated with older age, smoking and diabetes.



 Discolorations Of The Toenails:

Consider these other toenail color distortions:

  1. Red Spot Under The Toenail.
  2. White Patches On Toenails.
  3. Black Streaks Under The Nails
  4. Bruised Toenails