What is bruising?
Bruising is a very general term for a condition in which blood leaks out of the blood vessels into the tissues of the skin, mucus membranes or other organs, including muscles and bones. Different types of bruises include contusions, hematomas and purpura.
Contusions are common types of bruises that are caused by trauma, often blunt-force injury, that damages and breaks open the tiny blood vessels in the tissues of the skin, mucus membranes or other organs. Contusions are often accompanied by pain and swelling due to the body’s inflammatory response to injury. This is why a bruise on your shin caused by bumping a table can become swollen.
When a contusion develops in your skin, it turns red, then black and blue or purple, and finally a greenish-yellow shade as the blood is broken down and absorbed by the body. Bone contusions and deep muscle contusions can be very painful and take longer to heal than contusions that only affect the skin tissues.
The most serious type of contusions are contusions of important organs, such as the brain, kidneys, spleen, liver, lungs and heart. These contusions can be life threatening and are generally caused by severe trauma, such as a fall from a significant height, being hit by a car, serious crush injury, or motor vehicle accident, especially without wearing a seat belt.
Hematomas are a type of bruising in which there is significant bleeding that results in a collection of blood that pools at the site of injury. Hematomas can be caused by the same forces that cause contusions but generally cause more pain, swelling and complications than contusions.
Hematomas can be also be caused by surgical procedures or spontaneous rupture of a blood vessel, such as a ruptured aneurysm. Hematomas can occur in any area or organ of the body, and when they occur in certain organs, such as the brain or spleen, they can be life threatening.
Common hematomas include:
Epidural, subdural and intercerebral hematomas are collections of blood in the brain and/or under the skull, which can cause a critical increase in pressure in the skull and brain.
Nasal septum hematoma is a collection of blood that pools in the septum that divides the nose.
Subcutaneous hematoma is a collection of blood that pools just beneath the skin.
Subungal hematoma is a collection of blood that pools under a fingernail or toenail.
A shearing injury can also cause a hematoma in major organs. For example, shaking a baby can cause dangerous shearing forces inside the brain, a brain hematoma, irreversible brain injury, and death.
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Purpura is caused by spontaneous leaking of blood from tiny blood vessels (capillaries). It is a type of bruising that causes purple or red flat spots or patches on the skin and mucus membranes.
Purpura that results in tiny spots on the skin is called petechiae. A large area of purpura is called ecchymosis, although any type of bruising of the skin is often referred to as ecchymosis.
Purpura is not caused by trauma, as are contusions, but by a variety of medical diseases, disorders and conditions including:
Autoimmune diseases, such as lupus and rheumatoid arthritis
Certain infectious diseases, such as meningitis, mononucleosis and measles
Certain medications, such as aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), antibiotics, antihistamines, and blood thinners
Thrombocytopenia (low platelet count that causes problems with clotting)
Vasculitis (inflammation of blood vessels)
If you experience easy or frequent bruising, especially if it is associated with nosebleeds or bleeding gums, seek prompt medical care. If you, or someone you know, develops petechiae, which are small, flat, purple-colored spots that can indicate meningitis or other serious conditions, seek immediate medical care (call 911).
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- Bleeding into the skin. Medline Plus, a service of the National Library of Medicine National Institutes of Health. www.nlm.nih.gov/medlineplus/ency/article/003235.htm
- Bruises. Medline Plus, a service of the National Library of Medicine National Institutes of Health. www.nlm.nih.gov/medlineplus/bruises.html
- Bleeding and Bruising: A Diagnostic Work-up. American Family Physician. www.aafp.org/afp/2008/0415/p1117.html
- Intracerebral Hemorrhage. Internet Stroke Center. www.strokecenter.org/patients/ich.htm
- Subdural Hematoma. PubMed Health, a service of the NLM from the NIH. www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001732
- Purpura. University of Maryland Medical Center. www.umm.edu/ency/article/003232.htm