Subungual Haematoma

Skin and Nail Conditions· Also known as: blood under the toenail, black toenail, bruised toenail, subungual hematomaUpdated Oct 2026

Reviewed by Andrew Schox, BSc(Hons) PGradDipPod MPod, October 2026

At a Glance

A subungual haematoma is a pool of blood trapped under a toenail or fingernail, usually after a knock, a crush injury or repeated pressure. It is a common nail injury, and runners and people in sports like soccer and basketball are at higher risk. The nail turns dark red to black, and the trapped blood can cause throbbing pain. A small, painless one often needs no treatment. If it hurts, a practitioner can drain it, which gives quick relief. Most people do well.

What is it?

A subungual haematoma (sub-UNG-gwal hee-ma-TOE-ma) is blood trapped under a nail. The nail bed is the skin under your nail. When it is injured, it bleeds, and the blood has nowhere to go.

The nail is a tight space, so the trapped blood presses on the nail bed. That pressure is what causes the pain. Through the nail, the blood looks dark red, maroon or black. Many people call it a black toenail or a bruised toenail.

Who does it affect?

Anyone can get it. It is a common nail injury. Nail injuries make up as much as 8 per cent of hand emergencies, and blood under the nail is one of the two most common kinds. Children get it too, most often when a fingertip is caught in a door.

You are more likely to get it on a toe if you play sports like soccer or basketball, or if you run. Runners and dancers can get it from repeated pressure on the toes, such as the big toe. Ill-fitting shoes can also cause it.

People who take blood thinners or have a condition that affects blood clotting can be more prone to it. People with diabetes or poor blood flow to the feet may feel less pain, so they can be slow to get help.

Signs and symptoms

The most common symptom is sudden, throbbing pain after the nail is hurt. The nail turns dark, usually from maroon to black. Sometimes it looks blue-white.

If it happened recently, the colour is often bright red and the nail is tender when pressed. If it has been there a while, the colour is more purple-black and often doesn't hurt. A small haematoma with no pain usually needs no treatment.

What causes it?

The main cause is a single injury to the nail. Examples are dropping something heavy on your toe, a direct knock, or a crush injury.

Repeated small injuries can also do it. This can happen to runners, or to people whose shoes press on the toes. The pressure can build up over time without any one moment of injury.

How is it diagnosed?

Your podiatrist can usually tell from your story and an examination. They will ask how and when it happened. They will look at how much of the nail is dark and check the skin around the nail. They will also check the blood flow, feeling and movement in your toe.

An X-ray is usually advised, because a broken bone at the tip of the toe often goes with a haematoma. If a break is suspected, the X-ray is done before any draining.

Occasionally a dark nail is something other than blood. This includes some nail growths and a type of skin cancer of the nail called subungual melanoma. It can look like a bruise, especially when there was no injury. If your podiatrist is unsure, they may refer you or take a small sample (a biopsy) to be sure.

It helps to take a photo of the nail and note the date. That way you and your practitioner can see whether it changes.

Treatment

Treatment depends on how big the haematoma is and how much it hurts. A small haematoma, under about a quarter of the nail, may not need anything. Medical attention is advised if more than half the nail is involved or the pain is severe.

Looking after it at home

For a minor haematoma, use ice, keep your foot raised and take simple pain relief. Wrap the ice in a cloth. Don't put ice directly on your skin. Moderate to severe pain needs a practitioner to look at it.

Treatment from your podiatrist

If the pain is moderate to severe, the usual treatment is trephination (tre-fi-NAY-shun). Your practitioner makes a tiny hole in the nail so the blood can escape. They may use a fine needle or a heated tool. The pain eases straight away once the blood drains.

Afterwards, the area is covered with a clean dressing. Keep it clean and dry. Most people need no further treatment.

If the pain is bad, the nail will usually be drained or removed. How the nail looks afterwards doesn't seem to depend on which method is used. Complications are rare with any of them.

Other options

If you also have a broken bone at the toe tip, it is treated as well. Many breaks are only slightly out of place. They are often treated by gently setting the bone back and using a splint. A break that hasn't moved is watched. Digits with a broken bone usually need a follow-up visit at a fracture clinic. Open breaks, or breaks that involve a large part of a joint, need a specialist surgeon.

Surgery

A larger haematoma can hide a cut in the nail bed underneath. When more than half the nail is involved, about 6 in 10 people have a cut that needs repair. In that case the nail is lifted off and the nail bed is checked and stitched. The same is done if the nail itself is damaged, or if a break needs to be held in place. Severe injuries, where the nail bed is in pieces or torn away, are repaired at the emergency department.

Recovery

The outlook is good. After simple draining, about 85 per cent of people had an excellent or very good result. About 67 per cent had no lasting changes to the nail. Only 2 per cent had a poor result, because the nail split.

Problems can still happen, even with the best care. The nail can lift off the nail bed, change shape for a while or for good, or become infected. These are more likely if you have a long-term health condition or a more serious injury. People with diabetes or poor blood flow to the feet are at higher risk of complications. They heal more slowly and need care that is tailored to them.

After draining, keep the toe clean and dry. Go back if you notice more pain, redness, swelling or discharge. Nail changes can take time to settle, so be patient.

Preventing it

Wear shoes that fit and leave room for your toes. This matters most if you run or play sports that put a lot of pressure on your toes. It isn't clear yet that changing your shoes or habits stops it coming back, but well-fitting shoes are sensible anyway.

If you take blood thinners or have a clotting condition, tell your practitioner. If you have diabetes, check your feet every day.

When to see a podiatrist

When to book

Book an appointment with your podiatrist if your toenail has turned dark after a knock or crush injury and the pain is moderate to severe or throbbing. Book too if more than half the nail is dark. It's also worth going if a small dark patch worries you or you are unsure what caused it. Let your podiatrist know if you take blood thinners or have a clotting condition. If you have diabetes or poor blood flow to your feet, see your podiatrist promptly for any nail injury, because you may feel little pain.

When to get help sooner

Call your local emergency number if your toe suddenly turns cold and pale, white or blue, with pain or numbness. Call too if you have an injured toe or a wound and you also feel very unwell, with confusion or slurred speech, severe shivering or muscle pain, severe breathlessness, mottled or discoloured skin, or little or no urine. This could be sepsis.

Go to the nearest emergency department without delay if your toe becomes very swollen and tight with severe pain after a crush injury. Pressure can build up inside the toe, and this needs urgent treatment.

These signs need urgent medical assessment: see your GP today, or go to an urgent care clinic or the nearest emergency department.

Your toe sits at an odd angle, or a bone may be broken after an injury. A broken toe can look like a bruise.
The nail is torn, in pieces, or has come away from the nail bed.
Your toe or foot is swollen with visible pus, or has redness, warmth or a fever. This matters most if you have diabetes or a weakened immune system.

If you have diabetes and a cut, blister or bruise on your foot hasn't started to heal after a few days, or the skin on your foot becomes red, warm or painful, call your health care provider right away.

See your GP or podiatrist promptly if a dark nail has no clear injury behind it, keeps coming back, or gets darker. See them too if the dark patch isn't moving forward as the nail grows. Don't assume it is a bruise, as other nail conditions can look the same and need to be ruled out.

Frequently asked questions

Can I drain the blood under my toenail myself?

It is best not to. A broken bone often goes with this injury, and an X-ray should come first. A hole made in the nail can also let germs in. A trained practitioner can drain it safely, and you should get relief straight away.

Is a black toenail always blood from an injury?

No. Most often it is, but a dark nail with no clear injury, or one that doesn't move forward as the nail grows, may be something else. Your podiatrist can check it. A dated photo helps show any change.

Do I need an X-ray for a bruised toenail?

Often, yes. Breaks at the tip of the toe commonly come with blood under the nail. An X-ray from several angles can show whether the bone is broken, and that changes the treatment you need.