Hematoma: Symptoms, Causes, Types, Treatment, and When to Seek Care

Quick Answer

A hematoma is a localized collection of blood that forms outside a blood vessel after it is damaged. It can appear as a swollen, discolored area or a firm lump under the skin, but hematomas can also develop deeper in muscles, around organs, or inside the skull.

• Many small, superficial hematomas are similar to a bruise with a lump underneath and improve on their own.
• Deeper or internal hematomas—especially in the brain, abdomen, or behind the knee/inside the leg—can sometimes be serious.
• Seek medical care if the hematoma gets bigger, becomes very painful, does not improve, limits movement, or is associated with neurologic symptoms, chest pain, or abdominal pain.

What Is a Hematoma?

A hematoma develops when a blood vessel leaks or ruptures, allowing blood to collect in nearby tissues or spaces. Instead of spreading out thinly (like a simple bruise), the blood pools and clots in one spot, forming a more noticeable lump or swelling.

Common locations include:
• Under the skin (subcutaneous hematoma)
• Under a nail (subungual hematoma)
• In muscles (intramuscular hematoma)
• In or around organs (for example, splenic or hepatic hematoma)
• Inside the skull (intracranial hematoma)

Bruise vs. Hematoma vs. Blood Clot

Bruise (contusion)

• Caused by small blood vessels breaking near the surface of the skin.
• Blood spreads out in a thin layer, causing discoloration without a distinct lump.

Hematoma

• Involves a larger amount of blood that collects in one place.
• Often feels like a firm or rubbery lump under a bruise (“bruise with hard lump,” “pea-sized lump under bruise,” “big lump under bruise”).

Blood clot (thrombus)

• Forms inside a blood vessel.
• May be related to conditions like deep vein thrombosis (DVT) and has different risks than a superficial skin hematoma.

A hematoma is not the same as a DVT or internal blood clot in a vein, but both involve blood that has clotted.

Types and Classifications of Hematomas

Hematomas are usually classified by location:

Superficial / External Hematomas

Easier to see and feel; often related to minor trauma.

• Subcutaneous hematoma – under the skin, common on the leg, shin, thigh, arm, or buttock after a bump or fall.
• Subungual hematoma – under a fingernail or toenail after a crush injury.
• Scalp hematoma (“goose egg”) – a lump on the head after impact.
• Aural (ear) hematoma – between the skin and cartilage of the ear (e.g., wrestling, trauma).
• Septal hematoma – inside the nasal septum after nose trauma; can threaten nasal cartilage if not treated.

Deep / Internal Hematomas

Harder to recognize; may cause internal pain or swelling without obvious bruising.

• Intracranial hematomas
• Epidural, subdural, or intracerebral hematoma inside the skull
•Can compress brain tissue and are medical emergencies

• Retroperitoneal hematoma
• Behind the abdominal lining; may occur from trauma or in people on blood thinners

• Splenic or hepatic hematoma
• In or around the spleen or liver, often after abdominal trauma

• Intramuscular hematoma
•Within a muscle (e.g., thigh/hamstring); common in sports injuries

Location-Specific Concerns (Leg, Knee, Arm, Hand, Skin)

• Hematoma behind the knee (popliteal area)
May cause a visible or deep lump, pain, and difficulty bending or walking. Needs evaluation to rule out other issues (like a Baker’s cyst or DVT).

• Leg hematoma (thigh, shin, calf)
Often appears as a large bruise with a hard lump after impact. Larger muscle hematomas may be slow to resolve.

• Arm or hand hematoma
Can follow a fall, blow, or even blood draw. A firm swelling may appear under the skin.

• Buttock or hip hematoma
Common after falling on a hard surface. Large collections can be painful when sitting or walking.

• Head/scalp hematoma
A “goose egg” bump is often superficial, but any head injury with neurologic symptoms must be treated as a potential brain bleed.

If a lump under a bruise, especially on the leg or behind the knee, is increasing in size, extremely painful, warm, or associated with trouble walking, medical assessment is recommended.

What Does a Hematoma Look and Feel Like?

Typical features:

• Color:
• Early: red, deep purple, or blue
• Later: green, yellow, or brown as it heals

• Texture / Feel:
• A firm or rubbery lump under the skin (“lump under bruise”)
• May feel tender or sore when pressed
• Sometimes feels warmer than surrounding skin in the first days

• Size:
•Ranges from pea-sized to several centimeters or more.
•“Large hematoma” is less about a specific number in centimeters and more about whether it is expanding, painful, or affecting function.

A small hard lump after a bruise has healed often represents organized, clotted blood that the body is still breaking down. It may take several weeks to fully flatten, as long as it is not growing, red, hot, or very painful.

Symptoms of a Hematoma

Common Local Symptoms

• Swelling or a raised area
• Discoloration (bruise-like)
• Pain or tenderness
• A lump or knot under the skin
• Mild warmth at the site
• Stiffness or reduced movement if over a joint or in a muscle

Internal Hematoma Symptoms

• Deep, aching pain (chest, abdomen, back, or limb)
• Swelling or a sense of fullness without obvious bruising
• Dizziness, lightheadedness, or faintness if blood loss is significant
• Shortness of breath (if chest or large volume involvement)
• Pale, clammy skin in more serious bleeding

Brain (Intracranial) Hematoma Symptoms

Symptoms can appear immediately or hours to days after a head injury:

• Worsening or severe headache
• Repeated vomiting
• Drowsiness, confusion, or behavior changes
• Trouble speaking or understanding speech
• Weakness or numbness on one side of the body
• Unequal pupils
• Seizures
• A “lucid interval” (feeling okay after the injury) followed by sudden deterioration

These are emergency signs and require immediate medical care.

Causes of Hematomas

Common causes:
• Direct trauma (falls, bumps, sports, car accidents)
• Surgery or invasive procedures (including IVs and blood draws)
• Fractures or crush injuries
• Rupture of vessels inside organs (e.g., liver, spleen)
• Use of blood thinners (warfarin, DOACs, heparin) or antiplatelet drugs
• Bleeding disorders (low platelets, clotting factor deficiencies)

Hematoma “without injury”

Sometimes people notice a hematoma without recalling obvious trauma. Reasons may include:

• Small, unnoticed bumps (e.g., hitting furniture)
• Fragile blood vessels (older age, steroid use, sun-damaged skin)
• Medication-related bleeding tendency
• Underlying clotting or platelet disorders

Spontaneous or recurrent hematomas without clear injury should be discussed with a clinician.

Risk Factors

• Older age
• Blood thinner or antiplatelet use
• Clotting disorders or low platelets
• High blood pressure
• Frequent falls or balance problems
• Heavy alcohol use
• Recent surgery or major trauma

How Long Does a Hematoma Last?

Timeframes vary:

• Small superficial hematomas: often improve significantly in days to a couple of weeks.
• Larger muscle or thigh hematomas: may take several weeks to a few months to fully reabsorb.
• Subungual hematomas: usually improve with pain relief or drainage and then resolve as the nail grows out.
• Internal or intracranial hematomas: healing depends on severity, location, and treatment; they require medical follow-up.

A lump that is slowly shrinking, not red, not hot, and not more painful is usually healing. A lump that does not change, gets larger, or remains very painful should be reassessed.

Complications of Hematomas

Most hematomas are benign. However, possible complications include:

• Infection (redness, warmth, increasing pain, pus, fever)
• Pressure on nerves or blood vessels
• Reduced joint motion (if near a joint)
• Compartment syndrome in severe limb injuries (rare, but serious)
• Significant internal bleeding (retroperitoneal, organ, or intracranial hematomas)

A hematoma can contribute to serious illness or death when:

• It is intracranial (brain bleed) and not treated promptly.
• It is large and internal, causing major blood loss or pressure on vital structures.

This is not typical of simple skin or small muscle hematomas, but it explains why some hematomas are considered dangerous and why “when to worry” guidance is important.

How Doctors Diagnose and Classify Hematomas

Diagnosis can include:

• History and physical exam
• Palpation of the lump or swelling
• Neurologic exam if head or spine involvement is suspected
• Imaging when needed:
• Ultrasound – for soft tissue, muscle, or superficial hematomas
• CT scan – for head, chest, abdomen, pelvis
• MRI – for muscle, spinal, or deep soft tissues

Doctors also classify hematomas by size, depth, cause (traumatic vs spontaneous), and associated complications.

Treatment – How to Treat a Hematoma (Home Care vs Medical Care)

Home Care for Mild, Superficial Hematomas

Always follow your clinician’s instructions, but for many small, uncomplicated hematomas:

• Rest: Avoid activities that worsen pain or swelling.
• Ice: Use a cold pack wrapped in cloth for 15–20 minutes at a time during the first 24–48 hours.
• Compression: A light elastic bandage may help reduce swelling (if comfortable and not too tight).
• Elevation: Keep the limb up (above heart level if possible) to decrease swelling.
• Pain relief: Use over-the-counter pain relievers as directed by your clinician, especially if you are on blood thinners or have other conditions.

After the first 48 hours, some clinicians recommend warm compresses to support circulation and help the body reabsorb the blood. This should be done gently and stopped if pain worsens.

Avoid:
• Massaging a fresh or painful hematoma
• Applying excessive heat early, which can increase bleeding
• Changing or stopping blood thinners without medical advice

When Drainage or Surgery Is Needed

Medical procedures may be needed if:

• A subungual hematoma is large and very painful (nail drainage)
• A hematoma is large, tense, or limiting movement
• A hematoma is pressing on nerves or organs
• There is a brain or spinal hematoma increasing pressure
• A postoperative hematoma is causing pain, infection, or wound problems

Drainage or surgery is always decided by a clinician based on location, size, symptoms, and risk.

When to Worry About a Hematoma – and When to See a Doctor

Call a doctor or urgent care if:

• The lump is getting larger instead of smaller
• Pain is severe or worsening
• The skin becomes very tight, shiny, or hot
• You develop fever or the area becomes red and more painful (possible infection)
• The hematoma is near a joint and you cannot bend or straighten it
• You are on blood thinners and a large bruise or lump appears

Seek emergency care (ER) if:

• There is head trauma with headache, vomiting, confusion, weakness, seizures, or unequal pupils
• There is severe chest or abdominal pain
• You feel faint, dizzy, or short of breath
• The limb is very swollen, extremely painful, or numb, or you cannot move it
• Bleeding appears uncontrolled or rapidly expanding

When in doubt, especially for leg hematomas, hematomas behind the knee, or any internal pain, it is safer to seek medical advice.

Prevention Tips

You cannot prevent all hematomas, but you can reduce risk by:

• Wearing protective gear during sports and physical work
• Using seat belts and helmets
• Reducing fall risk (good footwear, home safety, managing vision and balance issues)
• Following instructions for blood thinners and getting recommended monitoring
• Applying pressure and keeping the arm straight after blood draws or IV lines as instructed

Frequently Asked Questions

Medical Disclaimer

This information is for general education only and is not a substitute for professional medical advice, diagnosis, or emergency care. Always consult a healthcare professional for personal medical concerns, and call your local emergency number or go to an emergency department for urgent symptoms.

APA Reference List

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