Unexplained Bruising

Unexplained bruising from time to time shouldn't concern you. However, unexplained bruises that happen regularly shouldn't be ignored, as they may point to a more serious underlying condition. Unexplained bruising may be associated with other symptoms, such as fatigue and soreness. Read more below to learn why you may be experiencing random bruising.

Unexplained bruising symptoms explained

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. You should not be too concerned if this happens once or very infrequently.

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.

Bruising, or ecchymosis, is most often caused by direct injury that you can likely remember, distinguishing it from unexplained bruising further described below. Bruising in this context (cuts, blows, falls or other trauma) is often quite 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.

Common characteristics of unexplained bruising

Unexplained bruising can likely be described by the following:

Common accompanying symptoms of unexplained bruising

If you're experiencing unexplained bruising it's also likely to experience:

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

What is causing your unexplained bruising?

Start a chat with Buoy AI assistant to find out what’s causing your unexplained bruising.

Free, private and secure to get you the best way to well. Learn about our technology.

What causes unexplained bruising?

Unexplained bruising can be the result of multiple causes, such as bleeding disorders, cancer, environmental causes, and medications.

Bleeding disorders

Bleeding disorders that can lead to unexplained bruising include the following [3-5].

  • 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.
  • Synthetic: Your liver, and to a 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.
  • 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.

Cancerous causes

In relation to blood disorders, some cancers can specifically affect the components of the blood [2]. 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.

Environmental causes

Environmental causes can be related to certain exposures or lifestyle habits.

  • 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 deficiency makes blood vessels weak and susceptible to breakage, resulting in bruising.
  • 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.


Medications that can lead to unexplained bruising may include the following.

  • Anticoagulants: People with conditions such as heart disease may take medications that thin the blood or decrease blood clotting factors 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.
  • Steroids: Corticosteroids 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.
  • 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 bruising.

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.

Rarity: Rare

Top Symptoms: unexplained bruising, slow wound healing, delayed ability to walk

Urgency: Primary care doctor

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.

Rarity: Rare

Top Symptoms: fatigue, nausea, shortness of breath, muscle aches, fever

Urgency: In-person visit

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.

Rarity: Ultra rare

Top Symptoms: fatigue, fever, new headache, diarrhea, irritability

Urgency: Hospital emergency room

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.

Rarity: Rare

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

Urgency: Primary care docto

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.

Rarity: Rare

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

Urgency: Primary care doctor

Hemophilia b

Hemophilia is a genetic disorder caused by missing or dysfunctional proteins, called factors, that are responsible for clotting blood and preventing excessive bleeding.

There are two main types of hemophilia — hemophilia A and hemophilia B. Although the two types have very similar signs and symptoms..

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.

Rarity: Rare

Top Symptoms: joint pain, spontaneous bone pain, thigh pain, hip pain that comes and goes, fever

Urgency: Primary care doctor

Acute lymphoblastic leukemia

Acute lymphoblastic leukemia is also called acute lymphocytic leukemia or ALL. It is a cancer that starts in the bone marrow where new white blood cells, or lymphocytes, are formed. Normal white blood cells are blocked and cancerous cells formed instead, causing the symptoms of the disease.

This blood cancer, or leukemia, can spread quickly through the bloodstream to other organs in the body.

ALL is caused by a genetic abnormality, which can be hereditary or can be acquired through overexposure to radiation. The disease is most common in young children and most are cured after treatment.

Symptoms include fatigue; shortness of breath; fever; aching extremities; unexplained bruising; and tiny red spots under the skin (petechiae.)

ALL can start and spread quickly, so it is important for the patient to see a medical provider at the earliest symptoms.

Diagnosis is made through blood tests and bone marrow tests.

Treatment involves some combination of chemotherapy and/or radiation therapy. Stem cell transplantation may be an option following the chemotherapy.

Rarity: Ultra rare

Top Symptoms: fatigue, loss of appetite, shortness of breath, fever, severe fatigue

Symptoms that never occur with acute lymphoblastic leukemia: inflamed throat

Urgency: In-person visit

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.

Rarity: Uncommon

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

Urgency: Primary care doctor

So... which condition is actually causing your unexplained bruising?

Free, secure, and powered by Buoy advanced AI to get you the best way to better. Learn about our technology.

At-home and medical treatments for unexplained bruising

At-home treatments for unexplained bruising

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 additional vegetables can ensure that your body receives all the nutrients it needs in order to help it function properly.
  • 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.

Medical treatments for unexplained bruising

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

  • Replacement therapies: If your 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.
  • Medication adjustments: If your symptoms are related to medication, do not stop taking the medications on your own. Always discuss medication changes with your physician first.
  • Chemotherapy, radiation, surgery, or a combination of the three: If your symptoms are due to cancer/leukemia, your physician will discuss the option that is best for your type, stage, and severity of disease.

When unexplained bruising is an emergency

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

  • Unilateral swelling in the foot, ankle or leg
  • Cramping calf pain
  • Severe, unexplained pain in the area
  • Warmth or redness of the area

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 a blockage (pulmonary embolism). This is a medical emergency.

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.

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 bodys 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.

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.

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.

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.

Buoy Chat Icon.
Take a thorough self-assessment on what you may have

Questions your doctor may ask about unexplained bruising

  • Have you ever been diagnosed with cancer?
  • Do you have a rash?
  • Have you been feeling more tired than usual, lethargic or fatigued despite sleeping a normal amount?
  • 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?

Self-diagnose with our free Buoy Assistant if you answer yes on any of these questions.

Share your story
Was this article helpful?
Read this next


  1. Blahd WH, Husney A, Romito K, eds. Bruises and Blood Spots Under the Skin. UW Health. Updated November 20, 2017. UW Health Link
  2. Bleeding Problems. Cancer.Net. Published May 2018. Cancer.Net Link
  3. Von Willebrand Disease. National Hemophilia Foundation. National Hemophilia Foundation Link
  4. Moake JL. Bruising and Bleeding. Merck Manual Consumer Version. Updated October 2017. Merck Manual Consumer Version Link
  5. Vora A, Makris M. An Approach to Investigation of Easy Bruising. Archives of Disease in Childhood. 2001;84;488-491. BMJ Link