What causes bruising?

Skin bruising is usually caused by a minor contusion or injury. You may find that you bruise more easily on your legs, because your legs are generally more prone to injury and the effect of gravity on blood flow. You may bruise easily from minor bumps or scrapes. This may simply be a familial, or inherited tendency to bruise easily and it is not necessarily a cause for concern. Easy bruising is also referred to as purpura simplex. However, frequent and unexplained bruising can also be a sign of something more serious, such as a blood clotting disorder or a blood disease, so contact your health care provider to discuss your symptoms.

In some cases, bruising is a symptom of a serious or life-threatening condition that should be immediately evaluated in an emergency setting.

Bruising due to injury

Bruising is often caused by everyday injuries or more serious trauma including:

  • Blunt force, such as a blow to the face

  • Child or domestic abuse

  • Falling

  • Motor vehicle collision

  • Sports injury

Bruising due to age, gender and lifestyle factors

Easy or unexplained bruising can be caused by age, gender and lifestyle factors such as:

  • Aging skin

  • Alcohol abuse (decreases blood clotting)

  • Female gender (women bruise more easily than men)

Bruising due to serious underlying diseases

A variety of diseases, disorders and conditions can cause bruising symptoms, including easy or unexplained bruising and purpura. Purpura is caused by spontaneous leaking of blood from tiny blood vessels (capillaries), resulting in purple or red flat spots or patches on the skin and mucus membranes. Some underlying causes of unexplained bruising or purpura include:

  • Aplastic anemia

  • Autoimmune diseases, such as lupus and rheumatoid arthritis

  • Certain infectious diseases, such as meningitis, mononucleosis and measles

  • Cushing’s disease

  • Hemophilia (inherited bleeding disorder)

  • Insect bites

  • Leukemia

  • Organ failure

  • Thrombocytopenic purpura diseases (potentially life-threatening platelet disorders that cause problems with blood clotting)

  • Vasculitis (inflammation of blood vessels)

  • Vitamin C deficiency (scurvy)

  • Von Willebrand's disease (inherited bleeding disorder)

Medications that can cause bruising

Always tell your doctor about any medications or treatments you are using including prescription drugs, over-the-counter medications, supplements, and herbal or alternative treatments. The following medications may be a possible cause of easy bruising or purpura:

  • Anticoagulants (blood thinners such as warfarin and heparin)

  • Antidepressants including serotonin reuptake inhibitors and tricyclics

  • Aspirin

  • Fish oil

  • Ginkgo biloba

  • Interferon

  • Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen

  • Penicillin

  • Plavix (antiplatelet medication)

  • Radiation or chemotherapy

  • Testosterone replacement therapy

What are the potential complications of bruising?

Complications associated with bruising can be progressive and vary depending on the underlying cause. Because easy or unexplained bruising can be due to serious diseases, failure to seek treatment can result in complications and permanent damage. It is important to contact your health care provider when you experience any kind of persistent or recurrent bruising or bleeding symptoms, such as lacerations or cuts that take a long time to stop bleeding. Once the underlying cause is diagnosed, following the treatment plan outlined by your doctor can lower your risk of potential complications including:

  • Coma due to brain contusion or hematoma

  • Compartment syndrome (complication of severe muscle bruise)

  • Hematoma

  • Hypovolemic shock and coma due to contusions or hematomas of organs such as the liver or spleen

  • Risk of fracture, especially in the elderly


  1. 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.
  2. Bruises. Medline Plus, a service of the National Library of Medicine National Institutes of Health. www.nlm.nih.gov/medlineplus/bruises.html.
  3. Bleeding and Bruising: A Diagnostic Work-up. American Family Physician. www.aafp.org/afp/2008/0415/p1117.html.
  4. Intracerebral Hemorrhage. Internet Stroke Center. www.strokecenter.org/patients/ich.htm.
  5. Subdural Hematoma. PubMed Health, a service of the NLM from the NIH. www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001732.
  6. Purpura. University of Maryland Medical Center. www.umm.edu/ency/article/003232.htm.

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.

... Read more about bruisingintroduction


What other symptoms might occur with bruising?

Bruising may be accompanied by other symptoms that vary depending on the underlying disease, disorder or condition. Skin bruises are often associated with local pain, swelling and skin discoloration. Easy bruising or unexplained bruising, which may be due to an underlying bleeding or blood disorder, may be accompanied by other bleeding symptoms.

Symptoms that may occur along w... Read more about bruisingsymptoms

Medical Reviewer: Cynthia Haines, MD Last Annual Review Date: Aug 1, 2013 Copyright: © Copyright 2014 Health Grades, Inc. All rights reserved. May not be reproduced or reprinted without permission from Health Grades, Inc. Use of this information is governed by the HealthGrades User Agreement.

This Article is Filed Under: Heart, Blood and Circulation, Skin, Hair and Nails