#579 How can a bruised toenail from running cause toenail fungus? - DOC

#579 How can a bruised toenail from running cause toenail fungus?

How can a bruised toenail from running cause toenail fungus? Well, that’s what we’re talking about today on the Doc On The Run podcast.



If you’re watching this episode, it’s probably not because you love toenail fungus. In fact, you probably think it’s pretty gross and you would be right. But this is a thing that happens and it is mostly preventable and there are certain circumstances that can really predispose you to getting the fungus infection in the nail that we call toenail fungus, or which doctors call onychomycosis and what this is, is that you get a fungus, usually, it’s the fungus that actually causes the skin infection called athlete’s foot. It’s very, very common. The fungus is all over the place. It’s probably in your shoes right now and whether or not it causes an infection, just depends upon the circumstances that you set up as a runner that actually allow it to get in and cause real trouble.

Now, if you look at your fingernails or your toenails, you can see that the toenails that are intact, the fingernails that are intact, the ones that have not been infected, they’re clear and you can basically see some pinkish tissue, which is the nail bed, right through the nail plate. Once it gets infected, then it’s a different story.

The nail starts to change. It gets thicker. It gets ugly. It starts crackling and crumbling and turns yellow or brown or all kinds of different disgusting colors, but it has to get infected and the nail is not typically infected because the fungus gets on the outer surface of the nail and eats its way through. It’s really because the fungus gets in between the nail plate and the nail bed underneath. How can that happen? Well, a couple of ways. You can smash the toe. If you smash the toe hard enough that you actually lift the toenail up off of the nail bed, well then the fungus can get in there and start causing the infection.

A good example of this is that one of my friends who is a podiatrist, she called me one day, somewhat in a panic because her son, his foot was smashed while playing soccer. So it was really smashed and she was worried about it and she called me and actually said, “Hey, can I borrow your laser because I want to treat my son’s toe preemptively to make sure that he doesn’t get a nail fungus infection.” Now, that is definitely overkill. I do not generally do that, but she was very worried about it. So I let her borrow my laser and do the laser procedure on his toenail to make sure it didn’t get infected.


When you get a bruise under the nail, let’s say you go out for a long trail run and you’re basically smacking the nail and the toe inside the shoe over and over and over in a way that actually causes a bruise under the nail. You may not even feel it when it’s happening. You might not even discover it until the next day or something. Maybe it feels a little bit sore that night, but the next day you notice it’s kind of black and blue.

Well, the question is, how does that cause a fungus infection? If you smash the toe and you lift the nail up, then it’s pretty obvious how that could get in there. But when you have this circumstance where you’re basically beating the toes on the inside of the shoe when you’re running on trails and it turns black and blue, there are a couple of ways that you can actually get fungus in there underneath the nail after that happens.

One of them is if you do one of these old tricks where you heat up a pin, or you take a tiny little drill and make a hole in the nail to try to drain the blood or the fluid out of that space and this is an old thing that has been done a lot. I typically do not do this because when you make that hole, you’re creating a way for the fungus to get in there. So if the fungus gets in there, it’s going to cause a nail infection. So that’s way number one, is that you make the hole that lets it in. The second way is if the bruise itself actually gets big enough and it actually separates the nail plate from the nail bed and then forms a blister at the end of the toe that looks like a blister and you pop that blister, then that can let the fungus get in and start to cause a nail fungus infection as well.

The other way, the fourth way, I guess, would be if you actually have the nail lifted off of the nail bed and it becomes loose and you have to cut the entire nail off as it starts to loosen and separate from the nail bed. But all of these are different ways that you’re basically creating a portal for infection or a way for the fungus to get in between the nail plate and the nail bed, and then set up this nail fungus infection.

There are lots of ways to prevent the bruising of your toes when you’re running on trails or doing marathons. You’ve got to take a little extra care to make sure that you don’t get the fungus in the nail and under the nail plate by the nail bed before this ever happens.

Prevention is key with this. So make sure you understand the steps that you can use to prevent the nails from turning black and blue. Check out the playlist on the Doc On The Run YouTube channel and you’ll see that I’ve done a number of different videos that talk about bruising under the nail and how to avoid those and some real simple tips that might actually help you prevent this from becoming a problem because it’s really difficult to treat the fungus once it gets in there.

So prevention is key. If you like this video, please share it with one of your friends, some other runner who’s beaten up their toes and getting black and blue toenails so that they don’t wind up with nasty toenail fungus infections either. Thanks for watching. I’ll see you in the next training.