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Top 9 Causes of Unexplained Bruising

How to tell when bruises are no big deal and when they might be a sign of a serious medical condition.
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Last updated February 2, 2024

Unexplained bruising quiz

Take a quiz to find out what's causing your unexplained bruising.

8 most common cause(s)

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Cushing's Syndrome
Hemophilia B
Chronic Kidney Disease
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Blood cancers (leukemia, lymphoma, myeloma)
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Von willebrand disease
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Immune thrombocytopenia
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Ehlers-danlos syndrome

Unexplained bruising quiz

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Bruises are a normal response to an injury or trauma such as a fall, a cut, or bumping into something hard, like furniture. These injuries can cause blood vessels near the surface of the skin to rupture. The blood from the vessels leaks into the tissues under the skin and gets trapped there, forming a bruise.

It’s also normal to experience more bruising as you get older. Your skin becomes thinner and more delicate, so even a minor injury may cause a bruise.

In addition, taking certain medications can also make you more likely to bruise. These include NSAIDs (nonsteroidal anti-inflammatory drugs like Motrin and Aleve), anticoagulants (blood thinners), steroids, aspirin, antidepressants, antibiotics, chemotherapy, and supplements such as vitamin E and ginkgo biloba.

But if you’re getting a lot of bruises with no obvious cause, it may be a symptom of a serious medical condition, such as liver or kidney disease or even cancer. It’s very important to see your doctor right away if you’re experiencing unexplained bruising—especially if you have other symptoms like unintentional weight loss, fatigue, or a low-grade fever.

When to see a hematologist

"One important question to ask your doctor is “Do I need to see a hematologist?” A hematologist is a type of doctor who is an expert in bleeding disorders. If you have recurrent unexplained bruising without any trauma, bleeding from other areas of the body such as the nose or gastrointestinal tract, other family members who have similar symptoms, or if your blood tests show any certain abnormalities, you should see a hematologist for further evaluation." —Dr. Elizabeth Grand


1. Vitamin deficiency


  • Unexplained and easy bruising and bleeding
  • Fatigue
  • Swollen or bleeding gums
  • Corkscrew-shaped hair
  • Tooth loss
  • Mood changes
  • Heavy periods
  • Blood in stool
  • Blood in urine

Certain vitamins are important for blood clotting and healing, such as vitamins C and K. If you are deficient in these vitamins, you may bruise easily because your blood may not be clotting as it should.

A blood test will reveal if you have a vitamin deficiency. Treatment includes eating a more varied diet and taking vitamin supplements.

2. Liver disease


  • Unexplained bruising
  • Swelling in the abdomen
  • Spider-like red spots on your skin
  • Enlarged breasts
  • Fatigue
  • Confusion
  • Yellowing of skin and eyes
  • Vomiting blood
  • Dark stools

Your liver has many functions, including helping in digestion, removing waste from the body, and producing certain proteins. One type of protein made by the liver is clotting factors. Clotting factors help prevent and stop bleeding. If your liver isn’t functioning properly, it will not make enough clotting factors, which makes you more prone to bruising and bleeding.

There are many different causes of liver disease, such as hepatitis. See your doctor if you suspect a liver disorder.

Treatment of liver disease depends on the cause, but generally involves avoiding alcohol and not taking any medications that could do more damage to the liver. If liver disease is severe, a liver transplant may be necessary.

3. Kidney disease


  • Easy bruising
  • Swelling in the feet, ankles, and legs
  • High blood pressure
  • Fatigue
  • Itching
  • Confusion
  • Decreased urination
  • Blood in urine
  • Frothy urine

One of the kidneys’ jobs is to help your platelets function normally. Platelets are a type of blood cell that prevent bleeding. In kidney disease, platelets do not work properly, causing easy bruising.

If you have symptoms of kidney disease, see your doctor. They will run blood and urine tests to see if your kidneys are functioning properly. If kidney disease is suspected, an ultrasound or CT scan of the kidneys may be needed to determine the cause.

Treatment of kidney disease involves fixing any reversible problems that may be harming the kidneys, such as removing a kidney stone. You also need to avoid any substances that could cause more damage, such as alcohol.

In very prolonged or severe kidney disease, a treatment called dialysis may be required. Dialysis removes blood from the body, filtered through a machine that works just like a kidney, and then returns to the body. In some cases, a kidney transplant may be necessary.

4. Von Willebrand disease


  • Unexplained bruising
  • Bleeding more easily
  • Heavy menstrual periods
  • Nosebleeds
  • Bleeding after dental procedures
  • Heavy bleeding after giving birth
  • Blood in stool

Von Willebrand disease (VWD) is the most common inherited bleeding disorder, affecting up to 1% of the population. People with VWD have a deficiency of Von Willebrand factor, which is a protein that prevents and stops bleeding. So these people bruise more easily.

Both women and men can get VWD. But women are more likely to see a doctor because it causes very heavy periods.

Treatment involves avoiding any activities that increase the risk of bleeding. Medication may also be needed, particularly if you have to have surgery or are experiencing extreme bleeding.

5. Blood cancers (leukemia, lymphoma, myeloma)


  • Easy bruising
  • Low grade fever that may come and go
  • Unexplained weight loss
  • Fatigue
  • Tiny red dots under the skin
  • Night sweats
  • Shortness of breath
  • Dizziness
  • Lightheadedness

Blood cancers affect blood cells and account for nearly 10% of all cancers in the U.S., according to The Leukemia and Lymphoma Society. These cancers lead to low levels of platelets. A low platelet count makes you bruise easily—one of the telltale symptoms of blood cancers.

If you have symptoms of blood cancer, see your doctor immediately. Treatment may include chemotherapy, radiation, and bone marrow transplantation.

6. Cushing syndrome


  • Unexplained bruising
  • Weight gain in certain areas of your body (midsection, face, area between shoulders)
  • Fatigue
  • Elevated blood pressure
  • Stretch marks
  • Acne on face
  • Increase in face and body hair in women
  • Irregular menstrual cycle in women
  • Low libido

Cushing syndrome is a disorder caused by high levels of the hormone cortisol in the body. It may occur due to a tumor in the adrenal glands or pituitary gland in the brain. Long-term use of medications that have cortisol-like components, such as steroids, can also lead to Cushing syndrome.

Over time, high levels of cortisol may lead to serious disorders, such as diabetes, high blood pressure, osteoporosis, anxiety, and depression.

Treatment depends on the cause. If Cushing syndrome is related to medication, your doctor will adjust your medications. If it is caused by a tumor, surgery is usually required, though medication may be recommended as well.

7. Hemophilia


  • Large or deep bruises
  • Easy bleeding
  • Frequent nosebleeds
  • Tightness in the joints
  • Joint pain
  • Blood in the stool or urine
  • Unexplained irritability (in infants)

Hemophilia is an inherited condition that interferes with your blood’s ability to clot properly, leading to frequent bruising. Hemophilia can range in severity from mild to severe. It primarily affects men.

There are two types of hemophilia: Hemophilia A and Hemophilia B. Both types have similar symptoms but are caused by different genes in your body.

Most people who have hemophilia had it at birth. But in very rare cases, people develop hemophilia later in life when the body produces antibodies that attack the clotting factors in the blood. This type of hemophilia is called autoimmune hemophilia.

Bleeding from hemophilia can be prevented with a medication called emicizumab that improves the blood’s ability to clot. Replacement therapy—getting injections of clotting factors into the veins—may also be recommended. In people with severe liver disease and hemophilia, a liver transplant may be needed.

8. Ehlers-Danlos syndrome


  • Bruising easily
  • Joint hypermobility (being able to move your joints more easily than most, also referred to as being “double jointed”)
  • Joint pain
  • Stretchy skin
  • Fragile skin
  • Poor wound healing
  • Fatigue
  • Digestive problems such as heartburn, constipation, and abdominal pain
  • Dizziness

Ehlers-Danlos syndrome (EDS) is an inherited condition that affects connective tissue like tendons and ligaments. It can range from mild to severe.

There are several types of EDS and easy bruising occurs to some degree in all of them. Connective tissue is within and surrounds blood vessels, providing support and protection. In EDS, the connective tissue is weak, so blood vessels are more easily damaged. Because connective tissue is located all throughout our bodies, people with EDS can have a wide range of symptoms.

There is no cure for the condition. Treatment of EDS is focused on easing symptoms such as joint pain and improving joint function. This includes physical and occupational therapy, lifestyle changes, and pain medications such as acetaminophen (Tylenol) and nonsteroidal antiinflammatory drug (Advil and Aleve).

9. Immune thrombocytopenia


  • Easy bruising
  • Red spots under the skin
  • Unexplained nosebleeds
  • Bleeding from the mouth
  • Blood in the urine or stool
  • Heavy menstrual bleeding

Immune thrombocytopenia (ITP) is a bleeding disorder in which the blood doesn’t clot properly. This is due to a low level of platelets in the blood. You bruise more easily when platelet levels are low.

ITP can be triggered by an infection. When responding to the infection, the immune system may mistakenly attack the platelets, leading to ITP. The condition may be acute (one episode that resolves) or it can be chronic (lasting throughout your life).

Some cases of ITP are so minor that they may go undiagnosed. There are also severe cases that can cause life-threatening events, such as a brain hemorrhage, which is an emergency situation.

Treatment for ITP may include prescription medications to boost platelet production, steroids, and injections of immune globulin, which help boost platelet production. In some cases, surgery to remove your spleen may be recommended as a way to improve your platelet count. Your doctor may also recommend lifestyle changes, such as avoiding contact sports, to manage symptoms.

Other possible causes

A number of other conditions can cause unexplained bruising. These include:

Which medications can cause bleeding?

"Some of the most commonly taken over-the-counter medications, such as ibuprofen and naproxen, can be associated with bruising and bleeding. Also, supplements such as vitamin E and ginkgo biloba can increase the risk of bleeding and bruising. Just because something is marketed as “natural” doesn’t mean it is without risk." —Dr. Grand

When to call the doctor

If you’re experiencing unexplained bruising, it’s important to be on the lookout for additional symptoms that may be a sign of a more serious medical condition. Call your doctor if you have:

  • A low-grade fever or a fever that comes and goes
  • Unexplained weight loss or weight gain
  • Night sweats
  • Blood in your stool or urine
  • Coughing or vomiting blood
  • Excessive nosebleeds
  • Severe tiredness
  • Other skin changes like itching or changes in color
  • Shortness of breath
  • Dizziness
  • Swelling in your legs or arms

What tests will the doctor do?

"Your doctor may request some initial blood work, then have you come back in for more blood work, and maybe even have you come back a third time for additional blood work. This is not because we don’t know what we are doing, but because we have to evaluate the most common causes first, and then move on to less common causes once those are ruled out." —Dr. Grand

Should I go to the ER for unexplained bruising?

You should go to the ER if you have the following:

  • Confusion
  • High fever
  • Uncontrolled bleeding
  • Swollen, painful, warm, or very red bruise
  • Inability to move the area where the bruise is located
  • Loss of consciousness
  • Shortness of breath
  • Chest pain


At-home treatment

  • Eat a healthy, well-balanced diet to avoid nutritional deficiencies.
  • Keep track of the location and frequency of the bruising and whether it was caused by trauma (bumped leg, fell on arm, etc.).
  • Avoid activities that may make bruising worse, such as contact sports.
  • Avoid drinking excessive amounts of alcohol.
  • Keep track of all the medications and supplements that you take.

Other possible treatments

  • Prescription medication to treat underlying issues
  • Your doctor may recommend you stop taking medications that are causing bruising
  • Surgery
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The stories shared below are not written by Buoy employees. Buoy does not endorse any of the information in these stories. Whenever you have questions or concerns about a medical condition, you should always contact your doctor or a healthcare provider.
Dr. Grand is a board-certified Internal Medicine Physician. She received her undergraduate degree in Psychology from New York University (2010) and graduated from Rutgers-Robert Wood Johnson Medical School (2014) where she was inducted into the Gold Humanism Honor Society. She completed an Internal Medicine residency program at Cooper University Hospital (2017) where she served as a Chief Resident...
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