What is swelling or hematoma?
A hematoma is a pocket of blood beneath the skin or nail caused by a broken blood vessel. Hematomas are often associated with swelling and bruising, and they usually feel tender to the touch. Hematomas can also develop into a hard mass under the skin.
Because hematomas can affect the surrounding nerves and tissues, they can cause pain at or near the injury site. In many cases, no special treatment is needed and the body re-absorbs the blood over time. Depending on your symptoms and the size of the hematoma, your doctor may recommend draining the hematoma to speed recovery.
However, not all swelling is a result of hematoma. A common musculoskeletal symptom, swelling may also be a sign of another problem, such as:
- Sprain or strain
- Tendon tear (rupture)
- Direct injury, often being hit by a blunt object
What causes swelling or hematoma?
When tissues are injured, the blood vessels can get damaged. A hematoma is caused by blood vessels bleeding beneath the skin. This can occur after an injury – such as getting hit – or after surgery.
Your surgeon can stop bleeding during an operation, but sometimes hematomas occur after the wound is closed.
As the damaged blood vessels bleed beneath the surface of the skin, the blood collects and can cause pain, tenderness and swelling.
What are the risk factors for swelling or hematoma?
A number of activities or circumstances can cause a hematoma: contact sports, an accident, bumping into an object or having a medical condition that increases the risk of bleeding (e.g., hemophilia).
Certain medications can also increase your risk of swelling or hematoma: drugs that affect blood clotting (anti-inflammatories such as aspirin or ibuprofen), anti-platelet drugs (e.g., Plavix) or anticoagulants/blood thinners (e.g., warfarin, Coumadin).
What are the symptoms of swelling or hematoma?
Signs of a hematoma may include pain, a lump under the skin, swelling and discolored skin (purple, green-yellow and yellow beneath the skin).
Bruises (known as muscle contusions) may have a similar appearance. However, with a bruise the blood is dispersed in the tissues; with a hematoma, the blood pools in one spot.
How is swelling or hematoma diagnosed?
Unless you have a minor hematoma, it’s a good idea to see a doctor. He or she will first do a physical exam, which is often all that’s needed to make a diagnosis.
It can sometimes be difficult to distinguish a bruise from a hematoma. Your doctor may suggest an ultrasound or other imaging test to determine if you have a hematoma. You can’t do anything to treat a bruise other than give it time, but in some cases your doctor may drain a hematoma.
Tests such as X-rays can identify a different problem or additional injuries, such as a fracture or dislocation that may accompany the hematoma.
What are the treatment options?
For a minor hematoma, rest, ice, compression and elevation are the most common treatments. Ice the injury site for about 20 minutes, three to four times a day. After 48 hours or once the swelling has subsided, use heat (a warm bath or heating pad) to promote circulation and healing.
Over-the-counter medications such as acetaminophen (e.g., Tylenol) or ibuprofen (e.g., Advil) can help ease discomfort, as can topical creams or ointments that numb the skin. Avoid massaging the injury or the bleeding may start again.
More serious hematomas may require medical attention. In some cases, your doctor may drain the hematoma using a sterile needle – a procedure called aspiration. Pain, pressure and swelling usually significantly improve after aspiration because there is less pressure on the surrounding tissues.
Your doctor may also inject a hyaluronidase, an enzyme that speeds up your body’s absorption of the blood.
Hematomas under the nail usually go away with time. If they are very painful, your doctor can drill a small hole in the nail to allow the blood to exit, which relieves pressure and pain.
How is swelling or hematoma prevented?
Hematoma is often a result of an accident, which you can’t prepare for. However, if you play a contact sport, use the appropriate gear to protect yourself.
If you get injured, use the R.I.C.E. approach (rest, ice, compression, elevation) to minimize pain and swelling until you can see a doctor.
What is the short- or long-term impact of swelling or hematoma?
A hematoma can be painful, and it takes time for the injury to go away. Most hematomas take between two weeks and two months to disappear, unless the blood is removed via aspiration.
The majority of hematomas don’t have long-term effects; however, complications can sometimes arise:
- If you wait too long to treat a hematoma, you may have permanent muscle and nerve damage.
- You can get an infection if the skin was broken during the injury or when your doctor drains the hematoma.
- Recovery can take longer if you’re too active too soon after being injured.
- If the blood clot in the hematoma breaks down (which can happen if you’re too active before it heals), you may develop a scar, calcification (when calcium builds up in the soft tissue and causes it to harden) or stiffness.
See your doctor if you’re not sure about the seriousness of your hematoma.
Questions to Ask Your Doctor
- How can you tell that this is a hematoma and not a bruise?
- Is the hematoma causing any problems?
- What happens if it's not treated?
- What should I do to treat it?
- Will you need to drain it?
- What does draining it involve? What are the risks?
- How long will recovery take?
- What are potential side effects of a hematoma?
Our Medical Advisory Board
Wiser Motion's physician advisors review all information on the site to ensure its accuracy, relevance, and consistency with medical best practices.
James Herndon, MD
Orthopaedic surgeon at Massachusetts General Hospital (Boston, MA) and Professor at Harvard Medical School
Leslie Scott Matthews, MD
Chief of Orthopaedic surgery at the Union Memorial Hospital (Baltimore, MD) and Asst. Professor at Johns Hopkins Hospital
Peter Johnson, MD
Medical Director of occupational medicine and employee health at the McLeod Regional Medical Center (Florence, SC)