A hematoma is a collection of blood trapped outside of a blood vessel. It is what we think of as a bruise or a contusion. It is usually seen under the skin as a black and blue spot on your arm or leg, or a bump on your head after an injury. It can be almost anywhere on or in your body. It can also occur in an internal organ where it can be more serious.
A hematoma is caused by an injury with damage to small blood vessels. This causes blood to leak into the tissues. Blood forms a pocket under the skin that swells and looks like a purplish patch. Hematomas sometimes form under the skin from bleeding during childbirth and can be particularly serious. Another serious form of hematoma forms after a fall on the head, called a subdural hematoma.
Gradually the blood in the hematoma is absorbed back into the body. The swelling and pain of the hematoma will go away. This takes from 1 to 4 weeks, depending on the size of the hematoma. The skin over the hematoma may turn bluish then brown and yellow as the blood is dissolved and absorbed. Usually, this only takes a couple of weeks but can last months.
Limit motion of the joints near the hematoma. If the hematoma is large and painful, avoid sports and other vigorous physical activity until the swelling and pain goes away.
Apply an ice pack (ice cubes in a plastic bag, or a frozen bag of peas, wrapped in a thin towel) over the injured area for 20 minutes every 1 to 2 hours the first day. Continue with ice packs 3 to 4 times a day for the next 2 days. Continue the use of ice packs for relief of pain and swelling as needed.
If you need anything for pain, you can take acetaminophen, unless you were given a different pain medicine to use. Talk with your healthcare provider before using this medicine if you have chronic liver or kidney disease. Also talk with your healthcare provider if you have had a stomach ulcer or digestive tract bleeding, or are taking blood-thinner medicines.
Follow up with your healthcare provider, or as advised. If X-rays or a CT scan were done, you will be notified if there is a change in the reading, especially if it affects treatment.
When to seek medical advice
Call your healthcare provider right away if any of the following occur:
Redness around the hematoma
Increase in pain or warmth in the hematoma
Increase in size of the hematoma
Fever of 100.4ºF (38ºC) or higher, or as directed by your healthcare provider
If the hematoma is on the arm or leg, watch for: