Hematoma: What It Is and the Different Types

What is a hematoma?

When a blood vessel wall is torn, blood escapes into the surrounding tissue. If it spreads thinly through the tissue, you see a bruise. If it collects in one place, it forms a hematoma: a pocket of blood that clots and often feels like a firm, rubbery or spongy lump.

The body breaks the clot down gradually. Hemoglobin is converted into other pigments, which is why the skin over a hematoma changes color: red or purple at first, then blue, green, yellow and brown over 1 to 3 weeks. Deep hematomas may not change the skin color at all.

Hematoma vs bruise vs hemorrhage

See bruise (contusion) for more on ordinary bruises.

Types of hematoma

Hematomas under the skin and in soft tissue

• Subcutaneous hematoma: just under the skin, after a knock, a blood draw or an injection.
• Intramuscular hematoma: in a muscle after a direct blow, such as a "dead leg" (thigh contusion). A large one can rarely calcify into bone (myositis ossificans).
• Subungual hematoma: blood trapped under a nail after crushing it, which causes throbbing pain and a dark nail.
• Auricular hematoma: blood between the ear cartilage and its covering after a blow. If not drained, it leads to "cauliflower ear".
• Septal hematoma: blood in the nasal septum after a nose injury. It must be drained quickly to prevent septal collapse.
• Scalp hematoma: the "goose egg" after a head bump. In newborns, a cephalohematoma can follow delivery.

Hematomas inside the skull

• Epidural hematoma: bleeding between the skull and the brain's outer covering, usually from an artery after a skull fracture. A person may be lucid for a while before rapidly worsening. See epidural hematoma.
• Subdural hematoma: bleeding beneath the covering from torn veins. Acute ones follow major head injury. Chronic ones can develop slowly over weeks in older adults or people on blood thinners after a minor bump. See subdural hemorrhage.
• Intracerebral hematoma: bleeding within the brain tissue itself.

Hematomas in the trunk and abdomen

• Retroperitoneal hematoma: bleeding behind the abdominal organs, often linked to anticoagulants, trauma or procedures through the groin. See retroperitoneal hematoma.
• Rectus sheath hematoma: bleeding into the abdominal wall muscle, often after coughing in people on blood thinners.
• Hematomas of the liver or spleen after abdominal injury.

Hematomas in pregnancy

A subchorionic hematoma is bleeding between the placenta and the wall of the uterus in early pregnancy. Many resolve without harm. See subchorionic hematoma.

After surgery and procedures

Postoperative hematomas can form at wound sites, after breast or neck surgery, around pacemaker pockets, and at catheter sites in the groin. A spinal epidural hematoma after an epidural or lumbar puncture is rare but can compress the spinal cord.

Causes and risk factors

• injuries: falls, blows, sports collisions, crush injuries
• surgery, injections, IV lines and blood draws
• blood thinners: warfarin, newer anticoagulants, antiplatelet drugs such as aspirin and clopidogrel
• bleeding disorders such as hemophilia and von Willebrand disease
• low platelets from leukemia, liver disease or medicines
• older age, fragile vessels and heavy alcohol use
• aneurysms and abnormal blood vessels

Symptoms

Symptoms depend on location and size:

• Skin and muscle: a swollen, tender, firm lump with discoloration, and stiffness of the nearby joint.
• Head: headache, vomiting, drowsiness, confusion, weakness on one side, seizures or unequal pupils.
• Abdomen and back: pain, swelling, and signs of blood loss such as dizziness, a fast heartbeat and paleness.
• Limbs: severe pain out of proportion to the injury, numbness and tightness suggest compartment syndrome.

Diagnosis

Small hematomas under the skin are diagnosed by looking and feeling. Imaging is used for deep or internal ones:

• Ultrasound for soft tissue, muscle and pregnancy hematomas
• CT of the head or abdomen for internal bleeding
• MRI for spinal and some muscle hematomas

Blood tests check the blood count, platelets and clotting (INR, PT and aPTT), particularly for unexplained or recurrent hematomas.

Treatment

Minor hematomas

• Rest the area.
• Ice wrapped in a cloth for 15 to 20 minutes several times a day for the first 48 hours.
• Compression with an elastic bandage.
• Elevation above heart level.
• Pain relief: acetaminophen (paracetamol) is preferred, because NSAIDs such as ibuprofen can increase bleeding in the first day or two. Follow the label dose.
• After 48 hours, warmth and gentle movement help reabsorption and prevent stiffness.

Avoid massaging a fresh muscle hematoma, and avoid strenuous use of the muscle until pain allows.

Medical treatment

• Drainage: a needle or small incision to drain large, tense or infected collections, ear and septal hematomas, and painful nail hematomas (by making a small hole in the nail).
• Surgery: urgent surgery for many brain hematomas, spinal compression and compartment syndrome.
• Reversing blood thinners: with vitamin K, specific reversal agents or clotting factor concentrates when bleeding is serious.
• Treating bleeding disorders with clotting factors or other therapies.

Healing time and complications

Small skin hematomas fade in 1 to 3 weeks. Large muscle hematomas can take 1 to 3 months and may leave a firm lump that softens slowly. Complications include infection, calcification in muscle, pressure on nerves, and, for internal hematomas, significant blood loss or brain injury.

Frequently asked questions

What is a hematoma?

A hematoma is a collection of blood outside the blood vessels, usually clotted, that forms after a vessel is damaged. It often feels like a firm, tender lump under the skin. Hematomas can also form inside the skull, abdomen, muscles or other organs, where they may be more serious.

What are all the types of hematoma?

By location, the main types are subcutaneous, intramuscular, subungual (under a nail), auricular (ear), septal (nose), scalp, epidural, subdural, intracerebral, retroperitoneal, rectus sheath, subchorionic (in pregnancy), spinal epidural and postoperative hematomas. Seriousness depends mainly on where the blood collects.

How long does a hematoma take to go away?

Small hematomas under the skin usually disappear in 1 to 3 weeks. Larger muscle hematomas can take 1 to 3 months. If a lump is not shrinking after about 4 weeks, or is growing, see a doctor to check for an ongoing bleed, infection or another cause.

When is a hematoma dangerous?

A hematoma is dangerous when it is inside the skull, around the spinal cord or deep in the abdomen, when it presses on nerves or blood vessels, or when it keeps growing in someone on blood thinners. Warning signs include worsening headache, confusion, weakness, severe pain and dizziness.

Should a hematoma be drained?

Most do not need draining and are reabsorbed naturally. Drainage is advised for ear and nasal septum hematomas, painful blood under a nail, large tense collections, infected hematomas, and those pressing on nerves, the brain or the spinal cord.