A hematoma is a collection of blood outside of a blood vessel. It occurs because of an injury to the wall of a blood vessel, allowing blood to seep out into surrounding tissues where it does not belong. Small hematomas may reabsorb quickly, but larger ones can take weeks or months to fully reabsorb.
What is a hematoma?
A hematoma forms when a blood vessel wall is damaged, allowing blood to seep out. This commonly occurs with trauma or injury, but can also happen spontaneously or with certain medical conditions that affect clotting. When blood pools in the tissues, it forms a reddish-blue mass called a hematoma.
Hematomas can occur almost anywhere in the body, but are most common in skin and muscle. Some common locations include:
- Scalp – Often caused by a blow to the head
- Ears – Called an auricular hematoma or “cauliflower ear” when on the outer ear
- Eyelids – May cause a “black eye”
- Arms and legs – Often from IV placement or blunt trauma
- Intestines – Can be life-threatening if large
- Under the fingernail or toenail – Called a subungual hematoma
Hematomas vary greatly in size. Small ones may only be a few millimeters across, while large hematomas can be several centimeters to more than a foot long. The amount of bleeding and location impacts the size.
Stages of hematoma healing
A hematoma goes through several stages as it gradually reabsorbs over time:
- Swollen stage – The acute phase immediately after the bleed occurs. The area rapidly swells as blood accumulates.
- Dark purple stage – The pooled blood coagulates and loses oxygen, becoming dark reddish-purple.
- Blue-black stage – The hematoma turns bluish-black as the blood further breaks down but is still liquid.
- Greenish stage – White blood cells break down the clotted blood into biliverdin and bilirubin, giving the hematoma a greenish tint.
- Yellowish stage – The iron in hemoglobin is converted into ferritin and hemosiderin, creating a yellowish color.
- Reabsorption stage – The body gradually reabsorbs the broken down blood components and clears away the hematoma.
The timeline varies based on the hematoma size and location. A very small one may go through all the stages within a week. Large hematomas can take many weeks to months to fully reabsorb.
Timeline for reabsorption
The average timeline for a hematoma to reabsorb is:
- Small hematomas: 1-2 weeks
- Medium hematomas: 2-6 weeks
- Large hematomas: 6 weeks to 3 months
- Very large hematomas: Over 3 months
However, this can vary substantially based on:
Location on the body
Areas with lots of muscle tissue and good blood flow tend to reabsorb hematomas faster. Locations like the arms, legs, back, and buttocks clear hematomas quicker than less vascular areas like ears, fingers, and toes.
Cause and age of injury
A traumatic hematoma caused by a cut or blow may take longer to heal than one caused spontaneously. Repeated trauma to an existing hematoma further slows healing. Older hematomas tend to linger longer as the blood congeals and clots more.
Bleeding disorders
Hematomas reabsorb slower in people with bleeding disorders like hemophilia or vitamin K deficiency. Medications that thin the blood, like warfarin or aspirin, also delay hematoma healing.
Individual factors
Age, genetics, diet, lifestyle habits, and other health conditions affect healing rates. For example, hematomas tend to linger longer in older adults and smokers.
Here is a table summarizing the average reabsorption timeline based on hematoma size and location:
| Hematoma Size | Common Locations | Healing Timeline |
|---|---|---|
| Small (<5 cm) | Fingers, toes, ears, eyelids | 1-2 weeks |
| Medium (5-10 cm) | Limbs, buttocks, back, scalp | 2-6 weeks |
| Large (10-20 cm) | Limbs, buttocks, back, abdomen | 6 weeks – 3 months |
| Very large (>20 cm) | Limbs, abdomen, back | Over 3 months |
Factors affecting reabsorption time
Many factors can speed up or delay a hematoma’s reabsorption process:
Hematoma size
Larger hematomas have more blood to reabsorb and often thicker clots, so take longer to heal. A study in Plastic and Reconstructive Surgery found small hematomas under 5 centimeters reabsorbed in around 2 weeks. Large hematomas over 10 centimeters took a median of 5 weeks but sometimes over 20 weeks.
Location
Areas with more vasculature and blood flow, like muscles, reabsorb hematomas quicker than less vascular areas like subcutaneous tissue. Hematomas in confined spaces also tend to linger longer.
Age of injury
Recent hematomas within 48 hours of forming tend to reabsorb quickest. After a few days, the blood congeals and is harder to break down and reabsorb.
Bleeding disorders
Disorders impairing proper blood clotting often cause hematomas to persist longer. This includes hemophilia, vitamin K deficiency, thrombocytopenia, and anticoagulant medications.
Infection
Infected hematomas take longer to heal. Signs of infection include pus, foul odor, warmth, redness, and fever.
Blood thinners
Anticoagulant and antiplatelet drugs like warfarin, aspirin, clopidogrel and heparin reduce clotting so hematomas may bleed longer. However, these drugs may help reabsorption once bleeding stops.
Diabetes
Poor circulation and wound healing in diabetics often delays hematoma reabsorption. Tight blood sugar control helps minimize this effect.
Age
Elderly patients tend to have slower healing times due to poorer circulation and impaired immunity. However, hematomas in children can linger if the blood vessel wall is not strong enough to heal properly.
Genetics
Research suggests certain genetic factors affect wound healing and response to trauma. Individual variation in reabsorption rates partly depends on genetic makeup.
Nutrition
Poor nutrient intake negatively impacts wound healing and cell regeneration. Proper nutrition provides the vitamins and minerals needed for tissue repair.
Smoking
Smoking restricts blood flow and delays healing. One study found smokers took 42% longer for bruises to fade than nonsmokers.
Chronic diseases
Conditions like cancer, kidney disease, HIV, autoimmune disorders, and heart disease can impair healing and extend hematoma resolution.
Medications
Corticosteroids, chemotherapy drugs, and other medications may retard healing. However, drugs that improve circulation may accelerate it.
Considering all these factors can help estimate an expected timeline for a hematoma to fully reabsorb in a specific individual.
Treatments to speed reabsorption
While most hematomas gradually reabsorb on their own, certain treatments can help expedite the process and minimize complications:
Rest, ice, compression, elevation (RICE)
Resting the injured area, icing to reduce swelling, gentle compression, and keeping it elevated helps reduce hematoma size and promote healing.
Blood flow enhancement
Gentle massage, exercise, and medications improving circulation may help reabsorption by dispersing pooled blood and enhancing tissue repair.
Aspiration
For large hematomas, a doctor may aspirate or drain out some of the collected blood using a needle. This reduces pressure and lets the body focus on the remaining blood.
Medications
Drugs that help blood clotting or wound healing may be used in some cases. Anti-inflammatory medication can also aid the healing process.
Surgery
Surgeons may opt to cut open and drain particularly severe hematomas, especially in confined spaces like the skull or abdomen. This prevents complications from pressure.
When to seek medical care
Many minor hematomas can be cared for at home. But it is important to seek prompt medical attention if you experience:
- Rapid swelling or enlargement of the hematoma
- Signs of infection like fever, redness, warmth, foul odor, or pus
- Numbness, tingling, coolness, or blue color in the limb below the hematoma
- Difficulty moving or using the affected body part
- Dizziness, blurred vision, severe or worsening headache
- Bleeding that cannot be stopped
Large hematomas, certain locations like the skull or abdomen, and suspected internal bleeding warrant urgent medical care to prevent potentially serious complications.
Preventing recurrence
You can reduce chances of a hematoma recurring in the same spot by:
- Avoiding re-injury or trauma to the affected area while it heals
- Treating any bleeding disorders or stopping anticoagulant medications
- Quitting smoking to improve circulation and healing
- Eating a nutritious diet to provide wound healing nutrients
- Keeping the area protected and supported with bandages or compression
- Doing physical therapy exercises to strengthen blood vessels
- Using medication to prevent clot breakdown after severe hematomas
Conclusion
Most hematomas gradually reabsorb on their own, but healing times vary substantially based on the size, location, cause, and individual factors. Very small hematomas may resolve in just 1-2 weeks, while large or complicated ones can take many months to fully reabsorb. Treatments like draining, medication, and surgery may expedite reabsorption. With proper care, most hematomas will eventually fully resolve without complications.