Black Spot under the Toenail or Fingernail

Welcome to the Complete Guide for a  Black Spot under the Toenail or Fingernail!

A black spot under the toenail or fingernail can have a few major causes. The most common cause of black under your toenail is due to bleeding  that can come from dropping something onto your toe, getting stomped on or even closing the door on your finger. In athletes it can also be caused by repetitive rubbing against the inside of a shoe, for example in the case of long distance runners, it is frequently referred to as ‘Jogger’s Toe’. If you have definitely not had any friction against the tips of your toenails, but you have instead been exposed to f moisture- then it is likely a Pseudomonas infection. If you have not experienced any of these situations then you may be at risk for melanoma. Read the guide below for more information.

Runner’s toe– Runner’s toe occurs if the toenail is rubbing against the front of the shoe; even if it is not really painful, blood could accumulate in the form of leakage or blistering under the nail. This page is dedicated to treating runner’s toe.

Pseudomonas bacterial infection– If your nails have green or black little spots on them. This can occur if you are around moisture. **Smell your toes to see if they give off a Sweet grape-like odor- Seriously!**. The treatment for this is to go see your podiatrist for medication.

Toenail fungus– If your nails gradually become thick, discolored and crumbly under the border then read our comprehensive guide to toenail fungus.

Melanoma If you have an unusual streak of black pigment that is pain free and just appeared over a without any incident- it is essential that you read our guide to black streaks in your nail.


The Following Guide is for the Most Common Cause:

Bleeding under the Toenail or Fingernail


Signs & Symptoms

  • Throbbing pain from blood building up under your nail. Even slight irriation can be runner’s toe.
  • Usually the big toe or the second toe.
  • Black, blackish red or bruised toenail.
  • Loose toenail at the far end of the toe.

Who is at risk

-1 in 100 develop runner’s toe from shoe friction while running, but it is much more common in marathon runners and ultra marathon runners.

-Up to 55% of Marathon runners can develop runners toe in their running career.


When to Seek Treatment for pain under the toenail

If over 25-50% of the nail is involved there is a high chance of a broken toe or finger, there is also a chance that the cut under the nail may become infected and would need antibiotics.


Prevention for athletes

  • Steel toe cleats or boots are needed for sports that present the risk of getting stomped on.
  • Great Results = Wear shoes that are 1/2 a size bigger and see if that helps.
  • Clip the toenail to prevent rubbing. Trim them straight across without curving the corners.
  • Use a Brannock Device to properly measure your shoe, it is very likely that your shoe is too tight.
  • Switch from cotton socks- once they get wet they stay wet. Get a sock made from synthetic materials for the summer & synthetic wool like smartwool for the winter. Double layered socks also help with blister formation and runner’s toe prevention.
  • Lace your shoes more tightly if you run downhill to prevent increased friction.
  • Get your biomechanics evaluated by a podiatrist. A jogger’s toe very routinely leads to a change in your running pattern and can cause hamstring, hip, ankle or knee problems! Be careful that you don’t change how you run, it could take you months or years to stretch out the tight muscles that you develop as a result.
  • Click the toenail and then put some duct tape over it to prevent friction. Vaseline or petroleum oil may be used to further prevent friction.



Treatment for a Pain under the Toenail or Fingernail


Home Treatment

  • In the minor cases with slight irritation, the pain will resolve in 1-2 days without treatment.
  • Ice for 15mins, this helps with pain but also helps the injury heal faster in the long run. Wrap ice into a towel (or something frozen) and hold it for 15 mins until you are numb to the cold and the pain. This improves bloodflow, healing and decreases inflammation
  • Elevation- keep the arm or leg above your heart early on.
  • Pain medication- Anti-inflammatory
  • If the nail bed is detached- cut off the loose part of the nail.
  • To prevent infection, use an antibiotic ointment like bacitracin, neosporin or triple antibiotic. This is very important, the toes and fingers are very likely to develop an infection compared to the rest of the body.
  • Clip the toenail to prevent further rubbing & cover it with a thick bandaid or duct tape.

What can a Podiatrist do?

  • X-ray for a fractured finger or toe- very possible if over 25% of the nail is damaged.
  • Check for a cut or tear underneath the
  • Draining the blood
  • The toenail can be numbed with lidocaine so that the nail can be punctured with a drill or a hot needle pain free. The blood is drained and as the pressure drops the nail should be pain free.
  • Nail removal
  • If over 25-50% of the nail is destroyed, the skin under the nail should be inspected for a cut or infection. Lidocaine injection numbs the toe and this can all be done pain free.
  • Stitches that are absorbed by the skin in the next few weeks are used to close the skin underneath the fingernail and toenail.
  • If there is an infection, then antibiotics will need to be prescribed


For more on a Black Spot under the Toenail or Fingernail:

Subungual Hematoma

Good Luck!