Hematoma: Understanding Pooled Blood and When to Seek Emergency Care
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Quick Answer: 5 Key Facts
A hematoma is a collection of blood that fills a space inside the body, often pushing surrounding tissues outward. A bruise is a visible hematoma, but serious ones can be hidden in the skull or internal organs. Many result from injuries. Hematomas inside the skull are especially dangerous, while small surface ones are treated with rest, ice, compression and elevation. [1]
What the research says
Ice has less proof behind it than most people assume. A systematic review of 22 randomized trials of ice for acute soft-tissue injury found the trials were generally low quality (mean PEDro score 3.4 out of 10). There was marginal evidence that ice plus exercise works best after ankle sprain and surgery, little evidence that adding ice to compression made a significant difference, and no evidence of an optimal mode or duration of treatment. (Bleakley et al., Am J Sports Med, 2004) [2]
Delayed bleeding after a head injury is uncommon, but it happens. A systematic review and meta-analysis of 26 studies (7,218 head-trauma patients taking oral anticoagulants) found delayed intracranial hemorrhage on repeat CT in 2.0% of patients; 0.1% needed neurosurgery and 0.1% died. Risk factors included a Glasgow Coma Scale score below 15, loss of consciousness, post-traumatic amnesia and a more severe head injury score. (Pessôa et al., World Neurosurg, 2024) [3]
What Is a Hematoma?
A hematoma is a closed wound in which blood collects and fills a space inside your body because it cannot flow or drain out. Unlike a bleed where blood escapes from the body, the trapped blood can push surrounding tissues, such as skin or muscle, outward, leading to visible swelling and discomfort. [1]
Most people recognize hematomas as common bruises, but they can occur almost anywhere in the body. How serious one is depends on what caused it, how big it is, where it is, and whether it is pressing on or damaging something nearby, such as breathing or brain function. [1]
Type | Location | Potential severity |
Subdural / epidural | Inside the skull | High (potentially life-threatening) |
Subchorionic | During pregnancy | Varies (needs monitoring by a clinician) |
Muscle hematoma | Within muscle tissue | Varies (can press on nerves and cause pain) |
Subungual | Under a fingernail or toenail | Usually low (painful but rarely dangerous) |
Recognizing the Symptoms and Warning Signs
The bigger a hematoma is, the more likely it is to cause symptoms, and symptoms are also more likely when it fills a small space or sits next to critical tissue. Shallow hematomas are usually recognized by pain, swelling and the color changes of a bruise. Deeper ones can press on nerves, causing pins and needles, numbness or nerve pain. [1]
Emergency Red Flags
Hematomas inside the head or abdomen require immediate medical attention. Because the skull has limited space, blood buildup eventually presses on and damages brain tissue. Warning signs of a hematoma in the head include: [1]
A sudden, severe headache
Weakness or paralysis, especially on one side of the body or face
Nausea and vomiting
Trouble speaking or swallowing
Loss of balance or trouble coordinating movements
Seizures
Loss of consciousness or coma
A large hematoma from internal bleeding in the chest or abdomen can cause trouble breathing or changes in breathing, chest or abdominal pain, skin that turns pale, cold or clammy, and severe pain that has no clear reason or seems much worse than expected. [1]
When to See a Doctor
Talk to or see a healthcare provider if you have bruising that does not heal within two weeks, frequent or recurrent bruising you cannot explain, or bruising along with symptoms that could point to a deeper problem, such as muscle weakness, tingling or numbness, or color changes from poor circulation. Seek emergency care for trouble breathing, loss of consciousness, chest pain, a sudden extremely painful headache, one-sided weakness, vision changes or trouble speaking. [1]
Common Causes and Complications
Traumatic injuries are a key cause of hematomas. Blunt force, such as a fall or a car accident, can rupture blood vessels without breaking the skin, so the blood has nowhere to go. Bone fractures, especially complete breaks, head injuries and muscle contusions are common examples. [1]
Non-Traumatic Factors
Hematomas can also develop without an obvious injury. Causes include: [1]
Blood disorders: Clotting disorders such as hemophilia, or blood cancers such as leukemia and lymphoma.
Vessel damage: Ruptured aneurysms, aortic dissections, or high blood pressure leading to non-traumatic brain bleeds.
Medical procedures: Internal bleeding after surgery, or a "blown vein" during IV insertion.
Hematomas usually do not cause complications unless a lot of bleeding is involved. Possible complications include hypovolemic shock from major blood loss, ischemia when the pooled blood presses on vessels and stops blood from reaching nearby tissue, and nerve compression symptoms. [1]
Diagnosis and Professional Treatment
A healthcare provider typically diagnoses a hematoma with a physical exam, looking for skin changes and feeling the area, because hematomas feel different from healthy tissue. Imaging finds deeper ones: MRI is the best at showing hematomas, especially deep ones, while CT scans can show whether a hematoma in the skull is pressing on the brain. Ultrasound and angiography can also help. [1]
The Path to Recovery
Minor hematomas: Most respond to the RICE method: Rest the injury, apply Ice wrapped in a towel, use Compression with an elastic bandage, and Elevate the area above your heart. [1] The evidence for ice itself is limited, so it is best used as one part of overall care. [2]
Serious cases: Emergency treatment may include blood transfusion to replace severe blood loss, along with surgery to repair damaged vessels and tissue. [1]
Definitive procedures: Doctors may drain pooled blood with a needle (centesis) or remove it surgically when it presses on vital structures, and they treat the underlying cause, such as setting a broken bone or managing blood pressure or clotting problems. [1]
Conclusion
While most hematomas are minor bumps that fade with time, knowing the difference between a simple bruise and a serious internal bleed matters. By recognizing the emergency warning signs and getting timely care, you give yourself the best chance of preventing lasting damage and recovering safely. [1]
For more expert guidance on injury recovery and internal health, visit Rinnit.com.
Related Reading
Frequently Asked Questions
How long does it take for a hematoma to go away?
Minor bruises often fade within about two weeks. Cleveland Clinic advises seeing a healthcare provider if bruising has not healed within two weeks, and larger or deeper hematomas can take considerably longer for the body to reabsorb. [1]
Can I treat a hematoma at home?
Small surface hematomas, such as a bruise or a mild sprain, can be treated with the RICE method (Rest, Ice, Compression, Elevation). Deep, large or painful hematomas, or ones that come with other symptoms, need professional evaluation. [1]
Is a hematoma the same as a blood clot?
No. A hematoma is a collection of blood that has pooled outside the blood vessels, while a blood clot (thrombus) usually refers to blood that has solidified inside a vessel or heart chamber.
When is a headache a sign of a serious hematoma?
A sudden, severe headache after a head injury, especially with weakness on one side, nausea and vomiting, trouble speaking or loss of consciousness, is a major red flag for bleeding inside the skull and needs emergency care. [1]
Can high blood pressure cause a hematoma?
Yes. Chronic high blood pressure can weaken blood vessels and lead to non-traumatic brain bleeds, which can form hematomas. [1]
What is a subungual hematoma?
A subungual hematoma is blood trapped under a fingernail or toenail, usually after a crush injury such as slamming a finger in a door or having a toe stepped on. [1]
Can a hematoma cause a fever?
A fever is not a typical feature of a hematoma. A fever together with increasing pain, warmth or redness could signal an infected hematoma or another infection and deserves prompt medical review.
Why do hematomas change color?
As the body breaks down the hemoglobin in the pooled blood, a bruise shifts from red or purple to blue, green and finally yellow or brown.
Can a hematoma press on a nerve?
Yes. Hematomas can press on nearby nerves, causing a pins-and-needles feeling, numbness or nerve pain, and large ones may cause weakness in the affected limb. [1]
What is hypovolemic shock?
Hypovolemic shock is a life-threatening complication in which blood loss is so great that the heart cannot pump enough blood to the organs. It is a risk when a hematoma involves a lot of bleeding. [1]
Do I need surgery for a hematoma?
Most do not. Smaller hematomas usually need no treatment or only simple home care. Procedures to drain blood or surgery to repair damaged vessels are used for more serious cases, such as hematomas pressing on vital structures or ones caused by ongoing bleeding. [1]
What is the RICE method?
RICE stands for Rest, Ice, Compression and Elevation. It is the standard home treatment for simple bruises and sprains. Wrap ice packs in a towel to avoid frostbite, compress with an elastic bandage, and keep the injured area above heart level. [1]
Can infants get hematomas?
Yes. A cephalohematoma is a collection of blood under the scalp that can occur in newborns, often related to the birth process. [1]
Are hematomas preventable?
Most are not, because they result from unpredictable injuries or conditions. You can lower your risk by wearing safety gear such as helmets and protective padding, using a seat belt, managing chronic conditions, and training and exercising cautiously. [1]
What is a "blown vein"?
A "blown vein" happens when an IV needle goes through a vein or the vein ruptures, so blood leaks into the surrounding tissue and forms a small hematoma. [1]
References
Cleveland Clinic. Hematoma. Cleveland Clinic. Last updated November 14, 2024. https://my.clevelandclinic.org/health/diseases/hematoma
Bleakley C, et al. The use of ice in the treatment of acute soft-tissue injury: a systematic review of randomized controlled trials. Am J Sports Med. 2004;32(1):251-261. PMID 14754753. https://doi.org/10.1177/0363546503260757
Pessôa RL, et al. Incidence and Risk Factors of Delayed Intracranial Hemorrhage in Anticoagulated Head Trauma Patients: A Systematic Review and Meta-Analysis. World Neurosurg. 2024;192:190-200.e6. PMID 39265937. https://doi.org/10.1016/j.wneu.2024.09.018
Medical disclaimer
This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. If you think you may have a medical emergency, call your doctor or your local emergency number immediately.
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