Subungual Hematoma: Symptoms, Causes and Treatment

A subungual hematoma is a collection of blood beneath a fingernail or toenail, usually after a crush injury or direct trauma. Most cases are manageable, but evaluation helps rule out fractures, nail-bed injury, or signs that more treatment is needed.

Overview

A subungual hematoma is the medical term for blood collecting underneath a fingernail or toenail after an injury. It often happens when a finger or toe is slammed, crushed, pinched, or struck by a heavy object. The trapped blood has nowhere to go, so pressure builds beneath the nail and the area can become dark, tender, and intensely sore.

For many people, the most striking part is the color change: the nail may turn red, purple, brown, or nearly black in a small area or across most of its surface. While the appearance can be dramatic, the condition itself is usually straightforward. The important question is not only how it looks, but whether the nail bed, the bone underneath, or the surrounding skin has also been injured.

Because fingers and toes are used constantly, even a small injury can affect daily tasks, walking, work, or travel plans. That is why a careful, practical assessment matters. Some subungual hematomas settle with simple protection and time, while others benefit from medical drainage or an X-ray to look for a fracture.

Symptoms

The earliest and most common symptom is pain that starts soon after the injury. The discomfort may feel throbbing or pressure-like, especially if the blood collection is large. Touching the nail, wearing shoes, or using the finger can make the pain more noticeable.

Visible changes usually follow quickly. The nail may look bruised under the surface, and the dark area often expands over several hours. Depending on the injury, the nail may also be partly lifted, cracked, or accompanied by swelling and redness around the fingertip or toe.

• Throbbing or pressure under the nail
• Dark red, purple, brown, or black discoloration
• Swelling or tenderness around the nail
• Possible nail lifting or splitting
• Pain that worsens when the area is pressed

In more serious cases, the pain is out of proportion to the visible injury or the finger/toe may be difficult to move. That can signal a larger underlying injury, such as a fracture or nail-bed laceration, and should be assessed by a clinician.

Causes & Risk Factors

Most subungual hematomas are caused by a direct blow or crushing force. A door closing on a fingertip, a dropped tool, a sports injury, or a heavy object landing on a toe are common examples. Repetitive microtrauma can also contribute, especially in runners, hikers, or people wearing tight footwear for long periods.

The nail is a firm cover, but the skin and tissue beneath it are delicate and richly supplied with blood vessels. When those vessels rupture, blood becomes trapped under the nail plate. The larger the trapped collection, the more pressure it creates and the more intense the pain may be.

Certain circumstances make the injury more likely or can make recovery more complicated. Wearing shoes that crowd the toes, using hands in manual work, participating in contact sports, or having brittle nails may increase the chance of nail trauma. People taking blood-thinning medicines may also bruise more easily and should mention this to a doctor during evaluation.

Diagnosis

Diagnosis usually begins with a discussion of how the injury happened and a close examination of the nail, surrounding skin, and fingertip or toe. A clinician will look for the size of the blood collection, whether the nail is intact, and whether there are signs that the nail bed or bone may be involved.

In some cases, an X-ray is recommended. This is especially helpful if there is significant pain, major swelling, nail deformity, or concern for a fracture after a crush injury. Imaging can also guide whether the injury can be managed conservatively or whether additional treatment is needed.

It is also important to distinguish a traumatic hematoma from other causes of dark nail discoloration. When the history is unclear, or if the dark area does not grow out with the nail as expected, further evaluation may be needed. A careful diagnosis helps avoid missing more serious injuries while preventing unnecessary procedures.

Treatment Options

Treatment depends on the size of the hematoma, the level of pain, and whether the nail or bone has been damaged. Small, mildly painful collections often improve with rest, protection, and observation. Keeping the finger or toe elevated at first can help reduce swelling and throbbing.

When pressure under the nail is strong, a clinician may recommend drainage to release the trapped blood. This procedure is often done in a medical setting and may provide quick relief when performed appropriately. If a fracture or nail-bed injury is suspected, the treatment plan may be different and can include splinting, wound care, or referral to a specialist.

If the nail is significantly torn, loosely attached, or the surrounding skin is cut, the injury may need more detailed care. The main goals are to relieve pain, protect the nail bed, support proper healing, and preserve nail growth as much as possible. In international-care settings, this kind of assessment is often coordinated with imaging and specialist review so that a patient can return home with a clear follow-up plan.

• Observation and protection for minor injuries
• Drainage for painful pressure under the nail, when appropriate
• X-ray if fracture is suspected
• Wound care for associated cuts or nail-bed injury
• Splinting or specialist review for more complex trauma

Prevention & Self-care

Not every nail injury can be prevented, but a few habits reduce the risk. Wearing well-fitting shoes, using protective gloves during manual tasks, and staying alert around doors, tools, and heavy equipment can help protect fingertips and toes. Athletes may also benefit from sport-specific protective gear when appropriate.

At home, simple self-care measures often support recovery. Resting the injured digit, keeping it clean, and avoiding pressure from tight shoes or repeated impact can reduce discomfort. If the nail is tender, a loose bandage or protective covering may help, as long as it does not become too tight.

It is best not to cut into the nail or attempt drainage at home. Doing so can increase the risk of infection or worsen the injury. If pain is significant, the nail is lifting, or the skin is broken, professional evaluation is the safer route. Patients traveling for care should also plan for a short period of reduced activity and ensure they know how to protect the area during flights, walking, or transfers.

When to See a Doctor

Medical assessment is advisable when the pain is severe, the dark area covers much of the nail, or the injury followed a strong crush or direct blow. A doctor should also evaluate the injury if the nail is split, loosened, or partly detached, or if the finger or toe looks deformed.

Prompt care is important if there is trouble bending the finger, difficulty bearing weight on the toe, numbness, or an open wound near the nail. These features can suggest a deeper injury that may not be obvious at first glance. Children, older adults, and people with circulation problems or diabetes may need extra caution.

After the initial visit, follow-up is useful if pain is not improving, swelling increases, or the nail begins to show signs of infection such as warmth, pus, or spreading redness. If a fracture is diagnosed, the clinician may recommend additional monitoring until healing is clear. Acibadem Health Point’s multidisciplinary specialists and JCI-accredited hospitals can diagnose and treat this condition for international patients who need coordinated care abroad.

Recovery and Outlook

Most subungual hematomas heal well. Pain often improves first, while the discolored part of the nail remains visible until it grows out. Fingernails usually grow more quickly than toenails, so the cosmetic change may take longer to disappear on the foot.

In some cases, the nail may eventually loosen and fall off, especially after a larger injury. That can look worrying, but new nail growth often continues underneath. The new nail may appear ridged or slightly irregular for a while before it smooths out.

Good follow-up matters if the injury was significant. A clinician can check that healing is on track and advise when it is safe to resume sports, work, or travel-related activities. With the right care, the long-term outlook is usually favorable.

Frequently asked questions

This article is for general information only and is not a substitute for professional medical advice. Please consult a qualified doctor about your individual situation.