What happens if you don't get a hematoma treated? A look at the risks and complications

September 28, 2025 •

4 min read

While most minor bruises resolve on their own, a true hematoma, a collection of clotted blood outside a blood vessel, can have severe consequences if left untreated, especially depending on its location. It is crucial to understand the risks of ignoring these injuries.

Quick Summary

An untreated hematoma's outcome is highly dependent on its size and location, potentially leading to persistent pain, infection, nerve damage, or even life-threatening conditions like increased intracranial pressure or tissue death in severe cases.

Key Points

Intracranial Hematomas Are Life-Threatening: Untreated hematomas inside the skull can rapidly increase pressure on the brain, leading to severe brain damage, coma, or death.
Risk of Serious Infection: A collection of trapped blood in a hematoma can become a breeding ground for bacteria, potentially developing into a severe infection or abscess.
Potential for Tissue and Nerve Damage: Large or deep hematomas can press on nerves or restrict blood flow, causing numbness, weakness, and even tissue death (necrosis).
Compartment Syndrome is an Emergency: In the limbs, an expanding hematoma can cause compartment syndrome, a dangerous condition requiring urgent intervention to prevent irreversible muscle and nerve damage.
Chronic Complications are Possible: Even if a hematoma eventually heals on its own, it can leave behind scar tissue, causing chronic pain, stiffness, or other long-term functional issues.
Medical Evaluation is Often Necessary: Significant or symptomatic hematomas, especially after a head injury or for those on blood thinners, should always be evaluated by a doctor to prevent complications.

The Dangers of Ignoring an Untreated Hematoma

Many people confuse a simple bruise with a hematoma. While both result from damaged blood vessels, a hematoma involves a larger pooling of clotted blood that can create a firm, tender mass. For some minor, superficial hematomas, the body can reabsorb the blood over time without intervention. However, failing to seek treatment for certain types of hematomas—particularly those that are large, deep, or located in sensitive areas—can lead to severe and lasting complications.

Life-Threatening Intracranial Hematomas

Among the most dangerous are intracranial hematomas, which occur inside the skull and can have deadly consequences if not treated promptly. The rigid structure of the skull means there is limited space for any swelling or blood collection. As the hematoma grows, it exerts pressure on the brain, a condition known as increased intracranial pressure.

Types of Intracranial Hematomas and Their Risks

Subdural Hematoma: Often caused by head trauma, a subdural hematoma is a collection of blood between the brain and its outer lining (dura mater). If untreated, the pressure can cause brain damage, coma, or death.
Epidural Hematoma: This occurs between the skull and the dura mater, typically from an arterial bleed after a head injury. It can expand rapidly and is a medical emergency requiring urgent surgical evacuation.

Localized Complications from Untreated Hematomas

Not all serious hematomas are in the brain. Other locations can also lead to significant problems if ignored. The severity depends heavily on the amount of blood pooled and the fragility of the surrounding tissue.

Infection and Abscess: A hematoma is essentially a pool of blood trapped within tissues. This creates an ideal breeding ground for bacteria. If bacteria enter the site, it can result in a serious infection or abscess, which then requires drainage and antibiotic treatment.
Tissue Death (Necrosis): In a subcutaneous hematoma, a large collection of blood can increase pressure to the point that it restricts blood flow to the overlying skin. If the pressure exceeds the blood pressure in the capillaries, it can cause the skin to die and slough off, leading to a large, open wound.
Nerve Damage and Neurological Deficits: A hematoma expanding near a nerve or a bundle of nerves can compress it, leading to pain, numbness, tingling, or even permanent weakness or paralysis in the affected limb or area.
Compartment Syndrome: This is a severe complication of large hematomas within a confined space, most often in the limbs. Increased pressure from the swelling compromises blood supply to the muscles and nerves. Untreated, it can cause permanent tissue damage and loss of function.
Chronic Pain and Fibrosis: Even if a hematoma eventually resolves on its own, it can leave behind scar tissue (fibrosis) that leads to chronic stiffness, pain, or functional impairment. In muscles, this can develop into a condition called myositis ossificans, where bone-like material forms within the muscle.

Comparison: Treating a Minor Hematoma vs. Leaving It


Aspect	Minor Hematoma (Treated with R.I.C.E.)	Minor Hematoma (Left Untreated)
Healing Time	Often a week or two, depending on severity.	Weeks to months; the body slowly reabsorbs the blood.
Symptom Duration	Pain and swelling managed and reduced relatively quickly.	Pain, tenderness, and swelling may persist for a longer period.
Pressure Risk	Minimized by compression and elevation.	Increased risk of pressure on surrounding tissues or nerves.
Complication Risk	Very low risk of infection or other serious issues with proper care.	Small risk of chronic symptoms or infection, even if it eventually resolves.
Aesthetic Outcome	Bruise fades; area returns to normal.	Can result in a residual lump, hardened mass, or discolored skin.

The Importance of Medical Evaluation

While minor hematomas often don't need significant medical intervention, it is critical to know the warning signs that indicate a more serious condition. Any hematoma resulting from a head injury warrants immediate medical evaluation, regardless of its apparent size. Similarly, a hematoma that is rapidly expanding, causes significant pain, restricts movement, or shows signs of infection like pus, increased redness, or warmth requires a doctor's attention. Patients on blood thinners are also at a higher risk and should consult a physician for any significant hematoma. For further information on general health concerns, you can consult reliable sources like the Cleveland Clinic.

Conclusion: When to Seek Treatment

In summary, while the body can handle small hematomas, assuming all will resolve without intervention is a dangerous gamble. The location and size are the most important factors in determining risk. Ignoring an untreated hematoma can range from a minor inconvenience to a life-threatening emergency. Always err on the side of caution and seek a medical professional's opinion, especially if the injury is severe, located on the head, or exhibits concerning symptoms. Early intervention can prevent serious complications and ensure a complete recovery.

Frequently Asked Questions

A bruise typically appears as a flat, discolored area, while a hematoma is often a raised, tender, and firm lump under the skin due to a larger accumulation of blood. Hematomas also tend to be more painful and can take longer to heal.

Yes, a hematoma in the leg can be dangerous depending on its size and location. Large leg hematomas can cause significant swelling and pressure, increasing the risk of infection or compartment syndrome, which can damage nerves and blood vessels.

Signs of an infected hematoma include increased pain, persistent swelling, redness, warmth around the site, and possibly fever or pus. If these symptoms appear, seek medical attention immediately.

Yes, an untreated hematoma can cause permanent damage, particularly if it's intracranial (in the brain) or causes compartment syndrome. This can lead to lasting neurological problems, nerve damage, or restricted mobility.

No, not always. Many small hematomas resolve on their own as the body reabsorbs the blood. However, large, painful, or strategically located hematomas often require drainage, especially if they are causing pressure on vital structures.

The R.I.C.E. method stands for Rest, Ice, Compression, and Elevation. It is a common home-care treatment for minor hematomas to help manage swelling and pain. Resting the area, applying ice, using a compression wrap, and elevating the limb can aid healing.

You should seek emergency medical care for a hematoma if you experience a severe headache, confusion, loss of consciousness, vision problems, weakness, or unexplained severe pain. If the hematoma is the result of a head injury, it should always be evaluated promptly.