Read below about unexplained bruising, including causes, treatment options and remedies. Or get a personalized analysis of your unexplained bruising from our A.I. health assistant. At Buoy, we build tools that help you know what’s wrong right now and how to get the right care.

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Unexplained Bruising Symptoms

A bruise develops when a blood vessel ruptures near the surface of the skin. The blood leaks into the tissues under the skin and gets trapped, giving the black-and-blue appearance often associated with bruises. [2]

Bruising, or ecchymosis, is most often caused by direct injury. Bruising in this context (cuts, blows, falls or other trauma) is often normal. Bruises that happen as a result of this type of injury can heal on their own and do not require any special treatment, especially if there are no broken bones or organ damage. [2]

However, if you wake up one morning wondering where your most recent bruise and/or bruises came from or find that you are experiencing bruises on your body without direct trauma or injury this is classified as unexplained bruising. [3]

Unexplained bruising symptoms may also be associated with: ### [6,7,8,9]

Unexplained bruising usually signals more serious underlying conditions. It is imperative that you to seek medical attention promptly once you notice any of the above symptoms.

Unexplained Bruising Causes Overview

Unexplained bruising symptoms can be the result of multiple causes.

Bleeding Disorders

  • Functional. Medical conditions that affect the way different components of your blood function can result in unexplained bruising. For example, von Willebrand disease is a disorder that involves problems with proteins that clot the blood, so bleeding and bruising happens easily. [1]
  • Synthetic. Your liver and to lesser extent your kidney are organs that are very important in making the components of your blood that regulate bleeding. If there is a malfunction in these organs such as liver disease or kidney disease, you may experience bruising in different parts of the body. [2,3]
  • Quantitative. Some conditions result in low numbers of different blood components that are essential in clotting. For example, some autoimmune diseases attack and destroy platelets in the body resulting in easy bruising. Others are inherited disorders in which a person has low levels of blood components that are important for clotting blood. [3]

Cancerous Unexplained Bruising Causes

In relation to blood disorders, some cancers can specifically affect the components of the blood. These cancers, leukemias, occur when cells in the bone marrow grow rapidly and out of control. Unexplained bruising is often an early sign of these types of cancers in addition to fatigue, night sweats and unintentional weight loss. [3,4]

Environmental Unexplained Bruising Causes

  • Diet. Certain vitamins are important for blood clotting and healing. People who have prolonged deficiencies of nutrients such as vitamin K, Vitamin B12 and vitamin C can easily develop bruising due to dysfunction in the processes that these vitamins facilitate. For example, vitamin K is important for clotting and its deficiency can result in leaky blood vessels that result in bruises. Vitamin C is important for maintaining the strength and elasticity of blood vessels. Vitamin C deficiency makes blood vessels weak and susceptible to breakage, resulting in bruising. [2,3]
  • Exercise. Intense or excessive exercise (professional weightlifting, Crossfit) can cause blood vessels in the body to tear and break due to significant strain. This damage to the blood vessels results in bruising that can often seem unexplained. [3]


  • Anticoagulants. People with conditions such as heart disease may take medications that thin the blood or decrease platelet production to prevent dangerous clots in the heart. However, sometimes these medications work too well and in traumatic situations, bleeding takes longer to stop. More blood leaks into the skin's tissues and causes a bigger bruise. [2,3]
  • Steroids. Steroids can cause the skin to become thinner and as a result blood vessels lie nearer to the surface. This makes blood vessels easier to damage and bruises more visible. [5]
  • Aspirin. Aspirin can cause platelets to be less sticky and is the reason it is used for coronary heart disease / heart attacks. Aspirin can also sometimes cause easy bruisability. [5]

A.I. Health Assistant Causes for Unexplained Bruising

The list below shows results from the use of our A.I. Health Assistant by Buoy users who experienced unexplained bruising. This list does not constitute medical advice.

  1. 1.Ehlers - Danlos Syndrome

    Ehlers-Danlos Syndrome (EDS) is a rare inherited disorders that weakens connective tissues that support skin, bones, blood vessels, and other organs. This condition can result in the ability to overextend and easily dislocate joints, and in chronic pain in some people.

    EDS is a chronic, not life-threatening condition.

    Top Symptoms:
    unexplained bruising, slow wound healing, delayed ability to walk
    Primary care doctor
  2. 2.Blood Issue That Needs Further Testing

    Your blood cells form in your bone marrow. Sometimes, the bone marrow produces abnormal cells. These cells can crowd out the healthy blood cells, making it hard for blood to do its work.

    Dependent on the tests

    Top Symptoms:
    fatigue, nausea, shortness of breath, muscle aches, fever
    In-person visit
  3. 3.Macrophage Activation Syndrome

    Macrophage Activation Syndrome is a rare, but life-threatening disease caused by rheumatic diseases like Systemic Juvenile Idiopathic Arthritis and Still disease.


    Ultra rare
    Top Symptoms:
    fatigue, fever, new headache, diarrhea, irritability
    Hospital emergency room
  4. 4.Cushing Syndrome

    Cushing Syndrome is a hormonal disorder. The cause is long-term exposure to too much cortisol, a hormone that the adrenal gland makes. Sometimes, taking synthetic hormone medicine like corticosteroids to treat an inflammatory disease leads to Cushing's syndrome.

    Recovery depends on treatment method

    Top Symptoms:
    fatigue, headache, depressed mood, weight gain, back pain
    Primary care doctor

    Unexplained Bruising Checker

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  5. 5.Immune Thrombocytopenia

    Platelets are tiny cells in the blood that help form blood clots and seal minor cuts and wounds. Immune thrombocytopenia, also known as immune thrombocytopenic purpura (ITP), is a condition where there are not enough platelets in the blood, causing easy bruising and tiny reddish purple dots on the skin from bleeding under the surface.

    This is a complex condition that requires consultation from a doctor to determine its course.

    Top Symptoms:
    being severely ill, rectal bleeding, red stool, unexplained/excessive bleeding from cuts or wounds, unexplained bruising
    Symptoms that always occur with immune thrombocytopenia:
    being severely ill
    Primary care doctor
  6. 6.Hemophilia b

    Hemophilia B is an inherited (genetic) disorder which causes the blood to have a deficiency or absence of coagulation factor IX, which is a protein that is needed to create blood clots. This can result in bleeding that starts on its own, or uncontrollable bleeding after trauma or surgery.

    Lifelong condition.

    Top Symptoms:
    spontaneous shoulder pain, difficulty moving the shoulder, rectal bleeding, unexplained/excessive bleeding from cuts or wounds, prolonged bleeding
    Primary care doctor
  7. 7.Gaucher's Disease

    Gaucher's disease is the result of a buildup of certain fatty substances in certain organs, particularly the spleen and liver. This causes these organs to become much larger than normal and can affect their function.


    Top Symptoms:
    joint pain, spontaneous bone pain, thigh pain, hip pain that comes and goes, fever
    Primary care doctor
  8. 8.Acute Lymphoblastic Leukemia

    Acute Lymphoblastic Leukemia (ALL) is a cancer of the white blood cells. This disease most commonly affects children between the ages of 2-5 years, and is a much more rare disease in adults. People with this disease get sick very rapidly. First, they feel fatigue and dizziness, and eventually the disease leads to bone marrow failure.

    Prognosis is highly variable and dependent on the individual, so a consultation from an oncologist is required.

    Ultra rare
    Top Symptoms:
    fatigue, loss of appetite, shortness of breath, fever, severe fatigue
    Symptoms that never occur with acute lymphoblastic leukemia:
    inflamed throat
    In-person visit
  9. 9.Side - Effect(s) of Chemotherapy

    Unfortunately, chemotherapy has many side-effects, ranging from hair loss to fatigue to nausea. This occurs because the treatment affects not only diseased cells but also healthy cells.

    This is likely to last the duration of your treatment; however, symptoms can be managed with other medications.

    Top Symptoms:
    fatigue, loss of appetite, arthralgias or myalgias, dizziness, sore throat
    Symptoms that never occur with side-effect(s) of chemotherapy:
    headache resulting from a head injury
    Primary care doctor

Unexplained Bruising Treatments and Relief

If your unexplained bruising is due to environmental causes, there are many things you can do at home in order to curb your symptoms:

  • Eat a healthy, well-balanced diet. A diet containing leafy greens, whole grains, fruits and even more vegetables can ensure that your body receives all the nutrients it needs in order to help your body function properly. [10]
  • Control the amount and intensity of your exercise. Though exercise is one of the best things you can do for your body, everything needs to be done in moderation. [11]

If your bruising is due to a systemic condition, medications or cancer, your physician will suggest other treatments such as:

  • Replacement therapies. If your unexplained bruising symptoms are related to blood disorders that involve functional, synthetic or quantitative issues your physician may suggest injections or treatments that replace the components you lack. [12]
  • Medication adjustments. If your symptoms are related to medication, do not stop taking the medications on your own. Always discuss medication changes with your doctor first.
  • Chemotherapy, radiation, surgery or a combination of the three. If your unexplained bruising symptoms are due to cancer/leukemia, your doctor will discuss the option that is best for your type, stage and severity of disease. [13]

In addition, if you experience unexplained bruising in the context of the symptoms below, seek urgent medical care.

These symptoms could signal a deep vein thrombosis (DVT), a serious condition that happens when a blood clot forms in the veins deep inside the body. DVTs are serious and potentially life-threatening because they can travel to the lungs and cause blockage in the lungs (pulmonary embolism). This is a medical emergency. ( [14]

FAQs About Unexplained Bruising

Here are some frequently asked questions about unexplained bruising.

Can low iron cause unexplained bruising?

Yes, low iron can increase the risk of bruising. Severe iron deficiency can cause you to have low numbers of platelets, important players in the process of clotting of blood. With low platelets, you are at a higher risk of bleeding, including bruising. [15]

Why do I bruise so easily?

Bruising is caused by the extravasation of blood from vessels into the skin. Easy bruising can result from abnormalities affecting the blood vessels themselves, the surrounding skin, platelet number and function, or your body’s ability to clot blood. Causes that affect the aforementioned parameters include medications like aspirin, genetic conditions like hemophilia, or dietary insufficiencies leading to inappropriately low levels of important clotting factors. [10,15]

What would cause bruises to appear for no reason?

Bruises generally occur due to some sort of trauma that disrupts the integrity of the capillary wall. A lack of physical trauma related to a bruise raises suspicion of an underlying bleeding disorder. However, this can sometimes be misleading. Some people, particularly those who are fair-skinned, old, overweight, or female can develop bruising with minimal trauma, and may not remember being injured. Less commonly, severe abnormalities in platelet counts can cause spontaneous bruising. [6,11,15]

Can I stop myself from bruising so easily?

Preventing easy bruising depends on why it is occurring in the first place. In the case of medication-induced bruising, decreasing the dose of blood thinners (under the guidance of a physician) can prevent easy bruising. Ensuring that your levels of blood cells and clotting factors are at appropriate levels is the best initial measure to treat preventable causes of easy bruising. Important things to also consider include family history and diet. [2,6]

Are bruises ever dangerous?

Bruises themselves are self-limited, but can be dangerous if they occur in tissues such as the brain where space is limited, as continued bleeding leads to increased pressure. Bruises can also signify a more serious underlying process in the body that can be life-threatening. For example, leukemia can present with easy bruising due to the body's inability to appropriately produce the correct amount of blood cells. [6]

Questions Your Doctor May Ask About Unexplained Bruising

  • Q.Have you ever been diagnosed with cancer?
  • Q.Do you have a rash?
  • Q.Have you been feeling more tired than usual, lethargic or fatigued despite sleeping a normal amount?
  • Q.Lie down on your right side and have someone press deeply under your left rib cage (on the border between the back and stomach). Do you feel a large lump right below your lowest left rib that isn't normally there?

If you've answered yes to one or more of these questions, try our unexplained bruising symptom checker to find out more.

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Unexplained Bruising Symptom Checker Statistics

  • People who have experienced unexplained bruising have also experienced:

    • 8% Fatigue
    • 2% Lower Back Pain
    • 2% Muscle Aches
  • People who have experienced unexplained bruising had symptoms persist for:

    • 34% Over a Month
    • 26% Less Than a Week
    • 14% Less Than a Day
  • People who have experienced unexplained bruising were most often matched with:

    • 42% Macrophage Activation Syndrome
    • 35% Blood Issue That Needs Further Testing
    • 21% Ehlers - Danlos Syndrome
  • Source: Aggregated and anonymized results from visits to the Buoy AI health assistant (check it out by clicking on “Take Quiz”).

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  1. Von Willebrand Disease (VWD): Diagnosis. Centers for Disease Control and Prevention. Published January 16, 2018. CDC Link.
  2. Blahd WH, Husney A, Romito K. Bruises and Blood Spots Under the Skin. Mott Children's Hospital. Published November 20, 2017. Mott Children's Hospital Link.
  3. Unexplained Bruising: Causes, Diabetes Connection & the Life-Cycle of a Bruise. Safe Symptoms. Published June 13, 2018. Safe Symptoms Link.
  4. Myelofibrosis: Signs and Symptoms. Leukemia & Lymphoma Society of Canada. LLS Canada Link.
  5. Vorvick LJ, Zieve D, Conaway B, eds. Bleeding into the Skin. UF Health. Published May 14, 2017. UF Health Link.
  6. Bruising. UPMC Pinnacle. UPMC Pinnacle Link.
  7. Blood Clotting & Bleeding Disorders. MedStar Washington Hospital Center. MedStar Washington Hospital Center Link.
  8. Cancer Warning Signs. Teenage Cancer Trust. Teenage Cancer Trust Link.
  9. Leukemia - Chronic T-Cell Lymphocytic: Symptoms and Signs. Cancer.Net. Published August 2017. Cancer.Net Link.
  10. Eilers D. Easy Bruising. Renal Support Network. Published January 4, 2009. Renal Support Network Link.
  11. Kahn A. Bruises: Overview. AARP. Published February 15, 2013. AARP Link.
  12. Kahn A. Bleeding Disorders. AARP. Published February 15, 2023. AARP Link.
  13. Possible Side Effects of Chemotherapy for CLL. MacMillan Cancer Support. Published September 30, 2015. MacMillan Cancer Support Link.
  14. Deep Vein Thrombosis. NHS. NHS Link.
  15. March 2016 Bleeding Disorders Awareness Month. New Castle Presbytery. Published March 2016. New Castle Presbytery Link.