---
title: "Runner's Toe: How to Treat and Prevent a Black Toenail From Running"
description: "Runner's toe turns a toenail black after the toe keeps hitting your shoe. Learn what to do now, when to see a doctor, healing time, and how to prevent it."
url: "https://wisdomrunning.com/runners-toe/"
language: "en"
author: ["Alex Gorovenko"]
published: "2026-10-07T13:36:38.000-07:00"
modified: "2026-10-08T03:13:03.000-07:00"
tags: ["Training","Injury Prevention"]
---

# Runner's Toe: How to Treat and Prevent a Black Toenail From Running

![A runner jogs down a gentle tree-lined park path in morning light](https://wisdomrunning.com/content/images/2026/10/runners-toe-downhill-path-run.webp)

Runner's toe is a black, purple, or dark red toenail caused by repeated pressure inside your shoe. Blood pools beneath the nail, often after a long run, race, or hilly route. If there's little or no pain, care usually means protecting the toe and correcting your shoe fit while the nail grows out.

A nail that throbs with pressure in the first day or two may need a clinician to drain it. Some dark marks under a nail aren't from running at all. Here's what to do now, when to get it checked, whether to keep running, and how to prevent it from happening again.

## What does runner's toe mean?

The medical name for blood trapped beneath a nail is subungual hematoma. With runner's toe, each stride can press or rub the nail against the shoe. Over many miles, that repeated contact can damage the tissue under the nail and cause bleeding, as [Cleveland Clinic's podiatry guidance](https://health.clevelandclinic.org/how-to-prevent-and-treat-runners-toe) explains.

The big toe is the usual target. If your second toe is longer, it may take the hits instead. The trapped blood can look reddish, purple, brown, or black, and the color can shift as it ages, as [DermNet's overview of subungual hemorrhage](https://dermnetnz.org/topics/subungual-haemorrhage) explains.

The problem can develop gradually over weeks of training. If your foot slides in your shoes, it can also appear after a single race, a long run, or a hilly route.

![Runner seated on a park bench checking a bare foot after removing a sock](https://wisdomrunning.com/content/images/2026/10/runners-toe-post-run-foot-check.webp)

*Illustrative scene: a runner checks their toes after a hilly run.*

## Is it runner's toe or a different problem?

These signs suggest runner's toe, though they can't confirm the cause on their own:

-   The dark nail appeared after long runs, a race, a hilly route, or wearing new shoes.
-   It affects the toe that bumps against the end of your shoe.
-   You feel tenderness, soreness, or pressure in the nail.
-   Clear nail begins growing at the base over the next few weeks, with the dark area moving toward the tip.

That last point matters. DermNet notes that with a bruise under the nail, a clear edge of normal nail appears at the base within a few weeks because the nail keeps growing.

### Nail fungus

A fungal infection can also discolor a toenail, sometimes black. According to the [American Academy of Dermatology (AAD)](https://www.aad.org/public/diseases/a-z/nail-fungus-symptoms), fungus tends to make the nail thick, brittle, or crumbly, and the nail may lift away from the skin. [Shoes that make your feet sweat, damp socks, and a previous nail injury](https://www.aad.org/public/diseases/a-z/nail-fungus-causes) all raise the risk, which is why it can show up in runners. A dermatologist or podiatrist can confirm it and recommend treatment.

### Signs to get checked

Melanoma under a nail is rare, but it can also look like a dark mark. The [AAD lists these warning signs](https://www.aad.org/public/diseases/skin-cancer/types/common/melanoma/nail-melanoma):

-   A dark streak, often a brown or black band running the length of the nail, frequently on the big toe or thumb.
-   Darkening skin next to the nail.
-   The nail lifting from the nail bed.
-   The nail splitting down the middle.
-   A bump or nodule under the nail.

Also get a dark spot checked if it appeared without any injury or long run, doesn't move toward the tip as the nail grows, or keeps spreading. [Cleveland Clinic notes](https://my.clevelandclinic.org/health/diseases/subungual-hematoma) that a provider who suspects melanoma will refer you to a dermatologist. You don't need to diagnose it yourself. If something doesn't fit the runner's toe pattern, book a visit.

## How to care for a black toenail

Your next step depends on how the toe feels, as well as how it looks.

| What you notice | What to do |
| --- | --- |
| Dark nail, little or no pain | Leave it alone, keep it clean, and fix the shoe cause |
| Throbbing pressure in the first day or two | See a clinician soon; drainage works best within 24 to 48 hours |
| Loose or lifting nail | Don't pull it; trim only unattached edges and protect it |
| Redness, warmth, swelling, pus, or fever | Get it checked for infection |
| Dark streak, or a spot with no injury | See a dermatologist |
| You have diabetes, nerve damage, or poor circulation | Have it looked at instead of waiting it out |

### If there's little or no pain

A dark nail that isn't painful usually needs time to grow out. Keep the toe clean and let the nail grow. If an edge snags on socks, trim only the part that is no longer attached to the skin. For soreness, [Cleveland Clinic suggests ice](https://my.clevelandclinic.org/health/diseases/subungual-hematoma) wrapped in a soft cloth.

Next, work out what caused it. A black toenail calls for a closer check of your shoe fit, lacing, or route.

### If your toe throbs or feels full of pressure

Blood trapped under the nail can cause sharp, throbbing pain. A doctor or podiatrist can relieve it by making a tiny hole in the nail to let the blood drain. This is called trephination. [Cleveland Clinic says it works best within 24 to 48 hours](https://my.clevelandclinic.org/health/procedures/nail-trephination) of the injury, and DermNet gives the same 48-hour window for acute pain.

Only a healthcare provider should drain the blood, Cleveland Clinic says. Trying to drain the nail at home can cause infection, more damage, and a longer healing time. Never use heated paper clips or needles to drain it.

### When the nail gets loose

Don't pull the nail off. Cleveland Clinic quotes a podiatrist who warns that doing so can damage and scar the nail bed, possibly causing the new nail to grow in misshapen. Trim only a hanging edge that is no longer attached to the skin. Protect the toe with a light bandage to keep the nail from catching on your sock, and let it come off by itself. A podiatrist can remove it if it's painful or in the way.

### When to see a doctor

Get medical care if you notice:

-   Intense pain, or pain that keeps getting worse.
-   Bleeding that won't stop, or a deep cut.
-   Redness, warmth, swelling, pus, or fever; any of these may indicate infection.
-   Severe pain or swelling after you stubbed the toe or dropped something on it. You may need an X-ray to see whether a bone is broken.
-   Any melanoma warning sign listed above, or a dark spot without a clear cause.

If you have diabetes, nerve damage in your feet, or poor circulation, don't wait it out. The [CDC advises people with diabetes](https://www.cdc.gov/diabetes/diabetes-complications/diabetes-and-your-feet.html) to check their feet every day for changes to the skin or nails and to see a doctor about foot problems.

## Can you keep running with runner's toe?

Often, yes, when there's little or no pain and no warning signs listed above. Cleveland Clinic says reducing activity gives the nail a chance to heal, especially when it hurts.

Choose your activity level based on how your toe feels:

-   **Sore:** cut back on running or take a break until the soreness eases. If the toe throbs with pressure, see a clinician soon rather than waiting for it to settle.
-   **Mild or no pain:** keep running, but skip long runs and steep downhills until you've fixed whatever caused it.
-   **Loose nail:** trim only an unattached edge and protect the toe with a light bandage.
-   **Pain building during a run:** stop running and get it checked if the pain keeps getting worse.

Address the cause before your next long run. If your foot keeps sliding or the shoe keeps pressing on the nail, more miles can mean more damage.

## How long will runner's toe take to heal?

Pain from the pressure usually eases well before the nail looks normal. The color doesn't fade the way a skin bruise does. It leaves as the damaged nail grows out.

Toenails grow slowly. A [2010 study of 22 healthy young adults](https://doi.org/10.1111/j.1468-3083.2009.03426.x) measured toenail growth at about 1.6 mm (roughly 1/16 inch) a month, less than half the speed of fingernails. The big toenail grew faster than the other toenails. A bruise near the tip may grow out in a few months, while one near the base takes much longer.

Sources give different timelines:

-   [Cleveland Clinic](https://my.clevelandclinic.org/health/diseases/subungual-hematoma) gives six to nine months for a bruised nail to grow out completely and return to its normal color. Its page covers both fingernails and toenails.
-   The [AAD](https://www.aad.org/public/diseases/a-z/nail-fungus-treatment) gives 12 to 18 months for a toenail to regrow after removal, in guidance about treating nail fungus.

These are broad estimates from different clinical contexts, not a countdown for your toe. A small bruise near the tip can grow out before the whole nail is replaced; a nail that comes off needs to regrow. Where the mark sits, how fast your nail grows, and the extent of the damage all affect the wait. Cleveland Clinic also lists a thickened or disfigured nail among the problems runner's toe can cause, so preventing repeated injuries matters.

![Line chart: toenails grow about 1.6 mm a month, roughly 10 mm by 6 months and 19 mm by 12 months](https://wisdomrunning.com/content/images/2026/10/runners-toe-toenail-growth-timeline.webp)

*Average toenail growth from one small study, with Cleveland Clinic and AAD regrowth estimates shaded; individual rates vary.*

## How to prevent runner's toe

Start with when and where it happens. The pattern usually points to the fix.

| When it happens | Likely cause | Fix to try |
| --- | --- | --- |
| After downhill or trail runs | Foot slides forward on descents | Secure your heel and recheck laces before long descents |
| After races or your longest runs | Feet swell and toes take more hits over time | Check toe room late in the day; test race shoes on long runs |
| After switching shoes | Different length, shape, or toe box | Recheck fit with your running socks |
| Your heel lifts or slips | Loose fit lets the foot shift | Use the top eyelet for a runner's loop |
| Mostly on your second toe | It may be your longest toe | Measure toe room from your longest toe |
| On wet or sweaty runs | Damp socks slide and bunch | Use moisture-wicking socks that stay smooth |
| Toenails hit the shoe | Nails are too long | Trim straight across, not past the toe tip |

### Get the length right

The [American Academy of Orthopaedic Surgeons](https://www.orthoinfo.org/en/staying-healthy/athletic-shoes/) recommends at least 1/2 inch between your longest toe and the tip of the shoe. That's about a thumb's width. Try shoes on at the end of the day or after a workout, when your feet have swollen, and wear the socks you run in.

Measure from your longest toe, and fit your larger foot. A shoe that's too short is the obvious problem, but simply sizing up isn't a cure. A shoe that's too roomy lets your foot slide forward instead. Our guide to [how running shoes should fit](https://wisdomrunning.com/how-should-running-shoes-fit/) walks through the full standing test.

### Lock your heel in place

Toe room only helps if your foot stays back in the shoe. The firm back of the shoe, called the heel counter, should hold your heel securely. If your heel slips, tie a runner's loop, also called a heel lock, using the extra eyelet near the top of the shoe.

A [lab study of 20 runners](https://doi.org/10.1080/02640410802482425) found that lacing all the way to the top eyelet held the foot more firmly to the shoe, while low lacing appeared to let the foot slide. The study measured forces and pressures, not toenail injuries, so it supports keeping your foot secure in the shoe but doesn't prove that lacing prevents runner's toe. Our [break-in guide](https://wisdomrunning.com/how-to-break-in-running-shoes/) shows how to use that extra eyelet.

### Trim your toenails short and straight

Long nails catch the shoe first. Trim toenails straight across, as the [AAD recommends](https://www.aad.org/public/everyday-care/nail-care-secrets/basics/how-to-trim-nails), and keep them from extending past the tip of your toe. Cutting straight across also lowers your chances of an ingrown toenail.

### Pick socks that stay in place

Cleveland Clinic's podiatry advice says socks that wick moisture help keep your foot from sliding and bunching. Skip socks so thick that they make your shoes tight, and check for thick seams over your toes. Sweaty, damp socks also increase the risk of nail fungus. For ways to prevent rubbing from socks and shoe linings, see our [chafing guide](https://wisdomrunning.com/chafing-from-running/).

### Prepare for long runs and downhills

Downhill running pushes your toes toward the front of your shoe. Check that your laces are snug before starting a long descent. Running some flatter routes can reduce how often your toes are pushed forward.

Build up your long runs gradually as you prepare for a race. On some of those runs, wear your race shoes and socks. A long training run is a better time to discover a fit problem than race day.

### Padding is optional

For a toe that takes repeated hits, some podiatrists suggest cushioning it with silicone toe pads or caps. These may help, but they can't fix a shoe that's too short or too loose. Address fit and lacing first.

If black toenails keep happening after you've corrected your shoe fit, lacing, and nail length, see a podiatrist. The shape of your toes or the way your foot moves may also contribute.

## Frequently asked questions

### Will runner's toe clear up by itself?

Usually, yes. As the damaged nail grows out, the dark color goes with it. That can take several months, or longer when the entire nail needs to regrow. See a doctor if pain gets worse, you notice signs of infection, or the dark mark doesn't move toward the tip as the nail grows.

### Can I still run with runner's toe?

When there's little or no pain and no other warning signs, you can usually continue running. Cut back or take a break if your toe is sore. If it throbs with pressure, see a clinician soon. Hold off on long runs and steep downhills until you've corrected the shoe fit or lacing that caused it. Stop running and get it checked if the pain keeps building.

### Should I drain my black toenail at home?

No. Cleveland Clinic says only a healthcare provider should drain blood from beneath a nail. Trying to drain it on your own can cause infection and further damage. If the toe throbs with pressure, see a clinician soon, since drainage works best within 24 to 48 hours.

### Could my toenail come off?

It might. The nail can loosen and come off if enough blood builds up beneath it. Don't pull it off; trim only an edge that is no longer attached to the skin, protect the toe, and let a podiatrist remove it if it's painful. A new nail usually grows to replace it.

### Are my shoes too small if I have a black toenail?

Not always. Shoes that are too short can cause it, but shoes that are too loose can let your foot slide forward and cause it, too. Check that your heel stays secure and that there's at least 1/2 inch of space in front of your longest toe.

### How long does a toenail take to grow back after runner's toe?

Toenails grow slowly: one study of healthy young adults measured about 1.6 mm of growth a month. Cleveland Clinic gives six to nine months for a bruised nail to grow out, in guidance covering both fingernails and toenails. The American Academy of Dermatology gives 12 to 18 months for a toenail to regrow after removal, in guidance on nail fungus. These are broad estimates; a small bruise near the tip can grow out sooner.