How to tell when a bruise is really bad? Recognizing severe injury signs

October 1, 2025 •

4 min read

While most bruises are minor injuries that heal on their own, some can signal a much more serious underlying issue. A bruise that is particularly painful, swollen, or won't go away could indicate anything from a significant hematoma to deep vein thrombosis, making it crucial to know how to tell when a bruise is really bad and needs a doctor's evaluation.

Quick Summary

Recognize the signs of a serious bruise by paying attention to severe pain, unusual swelling, numbness, and discoloration that deviates from a normal healing timeline. Knowing when to seek medical attention can prevent serious health complications.

Key Points

Intense Pain and Swelling: Pain that worsens or is disproportionate to the injury, along with significant or rapidly increasing swelling, can indicate a serious issue like a deep hematoma or fracture.
Unusual Bruising: Frequent, large, or unexplained bruising, especially without a known cause, may signal an underlying health problem such as a clotting disorder or vitamin deficiency.
Delayed Healing: A bruise that does not begin to improve or fade after two weeks should be checked by a doctor, as it could indicate a deeper injury or hematoma.
Lumpiness and Hardness: The presence of a firm or lumpy area, known as a hematoma, indicates a larger, deeper blood pool that may need medical attention.
Numbness and Weakness: Numbness, tingling, or weakness in the limb with the bruise can be a sign of nerve damage or a serious condition like compartment syndrome.
Location Matters: Bruises on the head, eye, or abdomen require immediate medical evaluation, as they can mask internal injuries or more severe trauma.
Signs of Infection: Increased warmth, redness, pain, pus, or red streaks extending from the bruised area, along with a fever, require immediate medical attention.

Understanding a Normal Bruise

Bruises, also known as contusions, occur when small blood vessels (capillaries) beneath the skin break, and blood leaks into the surrounding tissue. The resulting discoloration, tenderness, and minor swelling are a normal part of the body's healing process.

A typical bruise goes through a predictable color progression as the body reabsorbs the blood:

Initial Stage (Red/Purple): Immediately after impact, the area may appear reddish due to fresh, oxygen-rich blood. It can quickly turn purple as the blood loses oxygen.
Blue/Black Stage: Within a day or two, the bruise darkens to a blue, black, or deep purple.
Green/Yellow Stage: After about 5 to 10 days, the bruise often turns green or yellow as the body breaks down the hemoglobin.
Fading (Yellow-Brown): Over the next one to two weeks, the bruise becomes a lighter, yellowish-brown color before fading completely.

Most normal bruises heal within two to four weeks with basic home care, such as the RICE method (Rest, Ice, Compression, Elevation). However, certain symptoms should trigger a closer look and potentially a trip to the doctor.

Recognizing the Signs of a Really Bad Bruise

Knowing when a bruise crosses the line from a minor annoyance to a serious health concern can be life-saving. The following signs suggest a more significant injury or underlying condition:

Severe Pain and Swelling

If the pain is far more severe than you would expect from the injury and seems to worsen instead of improve after a few days, it's a major red flag. Severe, rapidly increasing swelling that develops within 30 minutes of the injury is also cause for concern. This can indicate a significant internal injury or a large hematoma.

Bruises That Don't Heal or Spread

A bruise that doesn't start to fade after two weeks, or one that reappears in the same spot for no reason, should be evaluated by a healthcare professional. Similarly, if the bruise continues to grow in size or density, it may indicate ongoing bleeding.

Unexplained or Recurrent Bruising

If you begin to bruise easily or frequently without a clear cause, especially in unusual areas like your back, chest, or face, it may point to an underlying medical condition. This can sometimes be related to medication, vitamin deficiencies, or a blood disorder.

Signs of a Hematoma

Unlike a typical bruise, a hematoma is a larger collection of pooled, clotted blood that creates a firm, spongy, or lumpy mass under the skin. While many hematomas are not serious, if the lump grows rapidly or is extremely painful, it warrants medical attention.

Dangerous Complications Associated with Severe Bruises

In rare cases, what appears to be a severe bruise can mask life-threatening conditions. Be vigilant for these red flags:

Deep Vein Thrombosis (DVT)

A severe impact can damage a deep-seated vein, leading to a blood clot called DVT. While the bruising itself doesn't cause DVT, the injury can trigger it. Symptoms often appear in the calves and include leg swelling, pain described as a cramp, warmth, and redness.

Compartment Syndrome

This is a medical emergency that occurs when increased pressure inside a muscle compartment cuts off blood flow. It can be triggered by a very badly bruised muscle. Symptoms include pain far greater than the injury suggests, a feeling of extreme tightness or swelling, and numbness or tingling.

When to See a Doctor

It is important to know when to escalate care from home remedies to professional medical evaluation. Seek medical attention if you experience any of the following:

The pain or swelling is severe, rapidly increasing, or lasts more than a few days.
The bruise doesn't fade or show improvement after two weeks.
You get frequent, large, or painful bruises for no apparent reason.
You notice numbness, tingling, or weakness in the bruised limb.
There is a firm lump (hematoma) under the skin.
You suspect a broken bone or can't move a nearby joint.
You have a black eye with vision changes or difficulty moving your eyes.
The bruise is on your head, abdomen, or trunk and was caused by a significant impact.
You experience signs of infection, such as fever, pus, or red streaks.
You have other unusual bleeding, like nosebleeds or blood in urine.

Comparison Table: Normal Bruise vs. Severe Bruise


Feature	Normal Bruise	Severe Bruise (or Hematoma)
Appearance	Starts red/purple, fades through green and yellow.	Large, dark, possibly lumpy; may develop rapidly.
Pain	Mild to moderate tenderness that improves over time.	Intense pain, disproportionate to the injury, that may worsen.
Swelling	Minor swelling at the site of impact.	Significant or rapidly increasing swelling, may feel tight.
Lumpiness	A mild lump or firmness may be present.	A distinct, firm, or spongy lump (hematoma) is often palpable.
Healing Time	Typically resolves within two to four weeks.	May last longer than four weeks or fail to show signs of healing.
Associated Symptoms	None, other than the bruise itself.	Numbness, weakness, fever, red streaks, vision changes, or signs of internal bleeding.

Conclusion

While the vast majority of bruises are harmless and heal on their own, paying close attention to the severity and accompanying symptoms is essential for protecting your health. Learning how to tell when a bruise is really bad involves recognizing key red flags, such as disproportionate pain, excessive swelling, delayed healing, or unexplained appearance. If any of these warning signs are present, it is always best to seek professional medical advice to rule out more serious complications like DVT or compartment syndrome and ensure a proper diagnosis and treatment plan. For further reading on first aid for bruises, the Mayo Clinic provides comprehensive information.

Frequently Asked Questions

A minor bruise involves small, broken capillaries under the skin, resulting in discoloration. A hematoma is a more severe injury with a larger collection of pooled, clotted blood, which often forms a firm, painful lump.

While a bruise itself doesn't cause a blood clot, the injury that caused the bruise can, especially if it affects a deep vein. Symptoms of a deep vein thrombosis (DVT) include swelling, pain, warmth, and redness in the limb.

Any head injury with bruising, especially if accompanied by confusion, severe headache, dizziness, or loss of consciousness, requires immediate medical attention to rule out a concussion or internal bleeding.

Signs of infection include increased pain, swelling, warmth, and redness, as well as pus draining from the area or red streaks extending from the bruise. A fever can also indicate infection.

Compartment syndrome pain is typically much higher than expected for the injury and worsens with movement. It is often accompanied by a feeling of extreme tightness, tingling, or numbness.

Frequent or unexplained bruising, without a known injury, should be evaluated by a doctor. This can sometimes point to underlying issues like a clotting disorder or certain vitamin deficiencies.

Most bruises heal within two to four weeks. If a bruise is still very painful, swollen, or hasn't started to fade after two weeks, it warrants a doctor's visit.