Updated: August 18th, 2021
The black toenail; A runners right of passage? (everything you ought to know)

It’s odd to think your first black toe nail is more like a medal of honour in the running world, especially considering the reasons why they occur. If you’re a consistent runner who’s increased your weekly mileage, they are likely to be as regular as your post-race T-shirt’s, ice baths and bananas.

Maybe you enjoy your right of passage in form of a hampered toenail (or loss of one) but there are ways to reduce your toenail woes; stay tuned throughout the article and you’l be the go-to nail guide for all your running chums.

Why do runners get black toenails?

Your toenails take quite the pounding as your putting in the miles, damage occurring when your toenail repeatedly makes contact with the front or side of your shoes (which is why it occurs most commonly with the big or second toe). The discolouration of the nail is simply bruising or a trapped bleed.

Runners toenail

Usually black toenails are not painful itself, as more often than not, it is the repetitive collision with your shoe that creates pressure and pain; A micro trauma damaging surrounding blood vessels. So the more times you hit your toe, the more damage will accumulate.

Although some runners develop black toenails following a fungal infectionsomething we runners are particularly prone to since fungi thrives in moist environments (like the sweaty socks you love so much). There are, of course other reasons for black toenails such as:

  • Anemia (low iron)
  • Heart disease
  • Kidney disease
  • Diabetes
  • Melanoma (skin cancer)
  • Blood blister (from the friction and repetitive micro trauma)

But if you notice your black toenail after increasing your running mileage; that is much more likely to be the cause.

Signs and symptoms of ‘runners toenail’

Most common symptoms include:

  • Blackening, browning or red discolouration of toenail
  • Pain
  • Loose or lifted toe nails
  • Blood blisters
  • Pressure feeling under toenail
  • Loss of toenail

However if you develop an infection you may experience:

  • Sharp/throbbing pain
  • Redness
  • Swelling
  • Localised heat
  • Oozing pus
  • Unpleasant odour
  • Pain when putting on a closed toe shoe/when bending the affected toe

Runners toenail

How to treat a black toenail


If you find your black toenail has come off, apply pressure to the bleed until it stops. It would be really beneficial to apply antibacterial cream and cover with a bandaid/bandage. You will want to keep the dressing fresh so repeat each day, preferable after a shower, until the wound has healed (usually a week or two).

No bleeding:

So you notice your nail has fallen off but theres no bleeding; still use the antibacterial cream and bandaid/bandage to help the wound fight infection (as the wound is prone to infections at this stage).

Toe bandaid

Blood blister:

Treating a blood blister under the nail also needs some TLC. Especially if it has started to lift the nail DO NOT PULL THE NAIL OFF. I get it is tempting, but you could damage your nail bed (more risk for infection) and have a deformed nail re-growth, potentially more pain.
If too much blood collects under the nail, you may need a podiatrist to drain the blood which will offer some pain relief for you too.

“Some runners chose to hide their black toenails with nail polish. Yes it improves the look of your nail whilst it heals, it prevents the nail from breathing and isn’t healthy long term.” – Advice from podiatrist Dr.Botek

How to prevent runners toe from happening

  • Change your running shoes (and buy ones that properly fit). Think ahead too, and take the socks you tend to run in when trying on potential new running shoes. Be mindful that your feet swell so they need some room, but not too much that your feet slide around (or we will be back to square one with another black toenail!) buying your shoes from stores that specialise in running would be beneficial (with help from our guides too of course)
  • throwing a sport shoe

  • Keep your toenails short. This will help reduce the end of your nail making contact with your shoes (oh and clipping your nails straight will help avoid other toenail issues too like ingrowing nails).
  • Look at how you tie your laces. There are many different ways to tighten your laces, so have a search online and find out the best way that works for you. (And if you’re a no-shoe-lace-user, that might be why your feet are sliding around?)
  • Laces

  • Take it slower to increase your mileage. The recommended amount is 10% increase per week. Allow your body time to get used to your training demands, that includes your feet! You might find you need shoes with more support for prolonged distances. Similarly if you are transitioning from road to trail (or vice-versa) there is a difference in running technique, mechanics, demands on your body, let along the shoes you will need). So if you complete road marathons, don’t jump onto a trail marathon – adjust slowly.
  • Work on your run technique. Understanding the force-velocity curve, the implications on your running technique and how you can alter your training to make your running as effortless and economical as possible. (You may also find your foot striking patterns affect the impact on your toes too).
  • Incorporate cross-training into your schedule. Not only will this benefit your fitness, your mentality and ironing out any muscle imbalances you may have. It also decreases the risk of over-use injuries, your feet wont be taking the pounding they usually do from miles and miles on end.
  • group training workout

  • Wear cushioning socks. The socks you wear are important – ensure they are not too tight or too loose that they rub on the end of your toes. Also it is wise to invest in socks that are breathe-able and padded in all the right areas. Running socks tend to cushion at the heel and ball of your foot for extra support; soo how you feel in them (mine made such a difference!)
  • Consider silicone pads. Sometimes they absorb some pressure from pavement pounding so your feet don’t have to!
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