Definition

A hematoma is an accumulation of blood that occurs outside of a blood vessel due to damage to the vessel wall. This allows blood to leak into surrounding tissues where it doesn't belong. Hematomas can form in any blood vessel, including arteries, veins, or capillaries. One type of hematoma is a subcutaneous hematoma, also known as a bruise or ecchymosis, which forms under the skin due to injury to the blood vessel wall, usually in a vein close to the skin's surface.

Most people experience a hematoma at some point in their lives. While most hematomas are harmless, some can indicate more serious medical conditions.

Causes

The most common cause of a hematoma is trauma or injury. This can result from car accidents, falls, physical blows, fractures, head injuries, or gunshot wounds. Fractures often cause hematomas at the fracture site, especially when long bones like the femur or humerus are involved, leading to significant bleeding and a large hematoma. However, even minor trauma can cause a hematoma. Simple activities like aggressive sneezing or sudden twisting movements of limbs can lead to a hematoma. Subungual hematomas, or hematomas under the nails, are often caused by minor trauma such as stubbing a toe.

Medical procedures like injections (e.g., insulin, vaccines) may also cause hematomas, as the needle can damage surrounding tissue and blood vessels.

Subcutaneous hematomas can also occur spontaneously without a clear cause, especially in individuals with certain risk factors.

Risk Factor

Several factors can increase the risk of hematoma, including:

• Blood thinners or anticoagulants like warfarin, aspirin, clopidogrel, prasugrel, rivaroxaban, apixaban, and dipyridamole can raise the risk of spontaneous bleeding and make it difficult for the body to repair blood vessel damage. Certain supplements can also increase this risk, such as: 
• Vitamin E
• Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen
• Garlic supplements
• Ginkgo biloba 
• Conditions affecting blood platelets: diseases that reduce platelet count or function, such as viral infections (rubella, parvovirus, mumps, chickenpox, HIV, and hepatitis C), anemia, cancer, or vitamin D deficiency.
• Blood disorders; conditions like hemophilia and Von Willebrand disease affect the body’s ability to clot and can lead to hematomas.
• Chronic alcohol consumption can damage the liver, an essential organ in blood clotting. Liver dysfunction impairs the body's ability to stop bleeding, increasing the risk of hematoma.

Symptoms

Typically, the body can repair small blood vessel damage through the blood clotting process. However, if the damage is severe or extensive, the body's clotting mechanisms may fail, leading to continued blood leakage and hematoma formation. The larger the hematoma, the more blood clots it contains.

For a subcutaneous hematoma, the main symptom is a change in skin color, ranging from mild spots to large areas of discoloration accompanied by tissue swelling. As blood leaks out of the vessel, it can irritate the surrounding tissue, resulting in symptoms like:

• Pain
• Swelling
• Redness
• Warmth at the site and surrounding area

Diagnosis

A subcutaneous hematoma is usually diagnosed through a review of medical history and a physical examination. Based on the patient’s medical background, additional tests may be conducted to identify any underlying conditions contributing to the hematoma. These tests can include a complete blood count, blood clotting tests, metabolic and chemical panels, and liver function tests. If a fracture is suspected, an X-ray may be performed, while a CT scan might be necessary if the hematoma involves a head injury.

Management

Most subcutaneous hematomas resolve on their own as the body reabsorbs the trapped blood over time. The healing process involves several stages:

• Initially, the blood clot feels firm but softens as the body gradually breaks it down.
• The shape of the hematoma changes as the fluid is reabsorbed, and the swelling reduces.
• The color of the hematoma changes from blue-purple to yellow-brown, reflecting the breakdown of blood components. This color change signals the healing process.

Treatments for subcutaneous hematoma include:

• Resting the affected area
• Applying a cold compress, such as ice wrapped in cloth, for 20 minutes at a time, 4–8 times daily, to reduce swelling and pain
• Applying pressure to the hematoma with an elastic bandage
• Elevating the affected area above heart level to reduce swelling

Pain caused by a hematoma is often related to the inflammation around the blood. Over-the-counter painkillers can help relieve discomfort. However, if you are on blood thinners, consult your doctor before taking medications like ibuprofen, as they can increase the risk of gastrointestinal bleeding. If you have liver disease or blood clotting disorders, medications like acetaminophen should also be avoided. It's essential to consult a doctor when managing a hematoma related to underlying medical conditions.

In rare cases, the hematoma may continue to grow due to ongoing bleeding from the damaged blood vessel. In such situations, a doctor may need to surgically remove the hematoma.

Complications

A frequent complication of hematoma is infection. The accumulation of stagnant blood without fresh blood supply can create an environment conducive to bacterial growth.

Prevention

Accidents that cause hematoma are often unavoidable. If you are on blood thinners, it's important to avoid high-risk situations that could lead to injury. Ensure that you adhere to the prescribed dosage of blood thinners, as exceeding it can increase the risk of bleeding.

When to See a Doctor?

Most hematomas resulting from minor injuries resolve within a few days. However, if a hematoma develops after a serious incident, such as a car accident or a fall from a significant height, it’s essential to seek medical attention.

If you are on blood thinners, even minor injuries carry a higher risk of bleeding. In such cases, visiting a healthcare facility is recommended.

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