When to Worry About a Bruise

Bruising is a common physical symptom. What causes bruising and how do you know when a bruise is something you should worry about?

Sanaz Majd, MD
4-minute read
Episode #254

a photo of a dark bruise on skin

We've all experienced a bruise or two here and there throughout our lives. Some of us who are a bit clumsier may have seen a few more. Bruising is a very commonly reported symptom at the doctor's office. But it can infrequently be a sign of something more concerning. 

How do you know when a bruise is something you should worry about? And what causes them? 

What is a Bruise?

A “bruise,” or “ecchymosis” (the fancy medical term for a bruise), is a collection of blood and fluid underneath the skin where blood vessels lie to feed the skin and nearby tissues in the body (such as muscle). These blood vessels can leak and release blood into the skin layers and become easily visible.

Causes of Easy Bruising

What exactly causes these blood vessels to leak more easily?

There are three main ways it can all go haywire. There can be a malfunction with the blood vessel lining itself; there can be a problem with the surrounding tissue in which it feeds; or there can be a dysfunction in the body’s protective reaction—this protective reaction is to normally activate a blood clotting process to an injured or leaky blood vessel and helps “patch up” the boo-boo. In the latter, the clotting cascade, or process, includes some vital components, such as clotting factors, platelets, and vitamin K.

Here are more specific causes of these dysfunctions:

  1. Trauma: Trauma is the most common cause of bruising. A contusion at the site of the bruise can injure your superficial blood vessels and they can burst and release some of that blood. Even minor bumps and thumps can do it. You may have bumped into the couch without realizing it after you cleaned that glass of lime margarita, or perhaps another player smashed into your shoulder during football practice a couple of days ago. Or maybe you are just a little clumsy.
  2. Blood thinners: Aspirin, anti-inflammatories (such as ibuprofen and naproxen) are easily accessible over-the-counter and are an ingredient in some cough/cold concoctions. They block the activity of certain clotting processes. Corticosteroids, which are used for treatment of many ailments from asthma exacerbations to autoimmune disorders like lupus, can also cause blood thinning.
  3. Liver disease: Heavy alcohol intake (that affects the liver) or cirrhosis of the liver can cause blood thinning. The liver produces many of our vital clotting factors. These are the structures in our blood stream that help stop bleeding. If these clotting factors are lacking because the liver has shut down, then you can bleed.
  4. Bleeding Disorders: This is why hemophiliacs bleed—they are genetically missing one of these blood factors mentioned in #3 above. Besides hemophilia, there are a few other hereditary bleeding disorders that can cause easy bruising and bleeding. Von Willibrand’s Disease is another. A family history of one of these disorders or excessive bleeding is a tip off.
  5. Platelet dysfunction: Besides clotting factors, platelets are also released and produced by the bone marrow in order to respond to a bleed. If they are dysfunctional, or lacking, then it is a problem.
  6. Vitamin C and K Deficiency: Scurvy (vitamin C deficiency) is quite rare in the United States. Vitamin K deficiency is slightly more common. Malnutrition (think elderly), Celiac Disease, antibiotics, and other medications that interfere with Vitamin K (like Coumadin and cholestyramine) can cause easy bruising and bleeding. Vitamin K is an essential element in the clotting process.
  7. Hereditory disorders of tissues: Connective tissue disorders and Ehlers-Danlos Syndrome are diseases of the surrounding tissues provide less structural support for the nearby blood vessels and hence they tend to more easily injure. There’s usually a family history.
  8. Blood, lymph, and bone marrow cancers: This is a much less common, yet most feared, cause of bruising—and bruising is a highly common medical phenomenon. Also having increased nosebleeds, or bleeding elsewhere, in addition to easy bruising are especially concerning for these cancers. A simple blood test can often rule this one out.


Please note that all content here is strictly for informational purposes only. This content does not substitute any medical advice, and does not replace any medical judgment or reasoning by your own personal health provider. Please always seek a licensed physician in your area regarding all health related questions and issues.

About the Author

Sanaz Majd, MD

Dr. Sanaz Majd is a board-certified Family Medicine physician who graduated from Drexel University College of Medicine in Philadelphia. Her special interests are women's health and patient education.