8 Reasons for Random Bruises

bruises, also known as bruises contusion, which occurs when the tissue under the skin is injured. This damages blood vessels and causes blood to build up under the skin’s surface, leaving black, blue, purple, brown, green, or yellow marks.

However, bruises are usually nothing to worry about, and they tend to heal on their own within a few days or weeks.

Random bruising can occur without a clear cause or injury. Some people may be more susceptible to random bruising than others, and depending on the situation, you may need to see a healthcare professional. Read on to learn more about unexplained bruising, its causes, and when to seek medical attention.

What are the risk factors for random bruising?

There are multiple risk factors associated with random and easy bruising, such as genetics, age, and gender.

While there’s no evidence for a specific genetic component that causes random bruising, research shows that people who bruise easily often have close family members who suffer from it. When a person bruises easily, this can lead to random and unexplained bruises during daily activities that usually don’t lead to bruises.

Genetics and random bruising

In some people, random bruises can be genetically influenced simply because of their body makeup. For example, a person may have fairer skin and more fragile blood vessels, two factors that can make bruises more likely to develop and appear darker in color.

In addition to genetics, aging may be a factor in unexplained bruising. Older adults often experience random bruising as part of the natural aging process. This is due to weakened blood vessels, which are more prone to rupture even if the area is slightly injured. Sex can also affect bruising, as women bruise more easily than men.

What causes random bruising?

Unexplained bruising can occur for a variety of reasons, such as certain medications, nutritional deficiencies, and medical conditions.


Some medications may cause easy or random bruising as they affect the body. Specific drugs include:

  • aspirin
  • pain management medication, such as ibuprofen or naproxen
  • blood thinner

Blood thinners and random bruising

Blood thinners are used for people with clotting problems. Our blood clots naturally to prevent excessive bleeding from injuries. Blood thinners can prevent this clotting, which makes bruising more likely after minor injuries due to too much pooling of blood under the skin.

bleeding disorders

Bleeding disorders occur when blood doesn’t clot the way it should. There are several different bleeding disorders that can cause a person to bruise randomly, including:

  • Hemophilia A and B: Both hemophilia A and hemophilia B occur when the blood does not clot properly. Hemophilia A is a genetic disorder, while hemophilia B occurs when a person lacks a specific factor (factor IX) that promotes proper blood clotting.
  • Von Willebrand disease: This is an inherited bleeding disorder that can also cause problems with blood clotting.

blood disease

nutritional deficiencies

Nutrients are important for all bodily functions, and not getting enough vitamins and minerals can lead to various health problems. One health problem that a lack of nutrients can cause is unexplained bruising. There are several nutritional deficiencies associated with easy or random bruising, including:

  • Vitamin C: Vitamin C is important for many reasons, one of which is wound healing. Random bruising may occur if there is not enough vitamin C in the body.
  • Iron: Iron is essential for healthy blood cells. It helps carry oxygen throughout the body into cells, and without enough oxygen, the skin is more prone to bruising.
  • Vitamin K: Vitamin K plays a role in blood clotting. Without enough vitamin K, blood clots don’t form as quickly, leading to more blood under the skin, which can lead to bruising.

Vitamin C deficiency and leg bruising

While vitamin deficiencies can cause random bruising all over the body, one case report found that bruising was limited to the legs.


Diabetes is a chronic disease that develops when the body is unable to produce or use insulin, a hormone designed to control blood sugar levels. This condition can cause bruises to last longer than normal because it interferes with wound healing.

Diabetes and erythema on the skin

Red spots, also called blood spots, look similar to bruises, but they don’t appear from injuries. They are usually due to an underlying health condition such as diabetes. Other common causes of blood spots include low platelets, coagulation disorders, vascular inflammation, and vitamin C deficiency.

low platelets

Platelets are specific cells present in the blood. When certain blood vessels are damaged, platelets bind together to repair the problem. People with low platelet counts often bruise easily because there are fewer platelets in the blood to repair damaged blood vessels. A low platelet count, also called thrombocytopenia, has some potential causes, such as:

  • certain cancers, including leukemia and spleen cancer
  • Chemotherapy drugs
  • biological therapy
  • Radiation therapy to the bone marrow or pelvis
  • enlarged spleen

What you need to know about living with low platelets

Cushing’s syndrome

Cushing’s syndrome is a condition that occurs when blood levels of cortisol, a stress hormone, are too high. The syndrome causes easy bruising as it causes the skin to thin.

Ehlers-Danlos syndrome

Ehlers-Danlos syndromes are a group of inherited health conditions that negatively affect the function and structure of connective tissue such as skin, joints, and blood vessel walls. Therefore, easy bruising is often a symptom of Ehlers-Danlos syndrome.

non-Hodgkin lymphoma

This is a type of cancer that starts in lymphocytes, which are immune cells designed to help fight pathogens. If a person has non-Hodgkin lymphoma, especially in their bone marrow, it can lower blood cell counts and platelet counts, which can lead to clotting problems and random bruising.

What is the treatment for random bruises?

In many cases, random bruises require no treatment at all and heal on their own. If you are sore from a bruise, you can apply a cold compress to the area to slow blood flow. If you can, you can also keep the bruise above the heart to prevent further blood buildup.

Bruises caused by an underlying medical condition are resolved by treating the specific condition or disease. Therefore, if you have a bruise due to a medical condition, treatment options can vary widely.

when to call the doctor

Experiencing random bruising can be worrying, but it doesn’t always require a visit to the doctor. That being said, you should see your doctor if:

  • bruises that don’t go away
  • You don’t know where the bruises are coming from, and they appear often
  • Unusually painful bruises

Can you prevent random bruising?

It can be difficult to completely avoid bruising, especially if the cause is unknown.

Active people should take special precautions when participating in physical activities to prevent injuries that can lead to bruising. This can be done by wearing protective gear when you play sports or engage in other physical activities that can cause bruising.

VigorTip words

In many cases, unexplained or random bruising is nothing to worry about and may go away on its own within a few weeks.

If you find yourself bruising frequently and don’t know why, contact your healthcare provider because you may have an underlying medical condition or nutritional deficiency that should be to blame for the ongoing bruising.

What it means when you have a bone bruise

Frequently Asked Questions

  • What is a bone contusion?

    A bone bruise is a type of bruise that occurs when blood and fluid build up in and around the injured bone. This is a traumatic injury that is slightly less severe than a fracture.

  • Do bug bites leave bruises?

    While not everyone gets a bruise after being bitten by an insect, it’s entirely possible that you will get a small bruise if you are bitten by an insect. It is more common in certain insects.

  • How long does it take for a bruise to heal?

    Bruises usually heal on their own within two weeks of the initial injury. If you are sore from a bruise, you can apply cold compresses and keep the bruise above your heart. This may help speed up the healing process because it reduces inflammation and prevents more blood from pooling in the area.

  • Why are my bruises yellow or green?

    Bruises often change color as they heal. A bruise usually turns yellow or green about 5 to 10 days after the injury because the body produces specific compounds to break down blood that collects in the area. These compounds, called biliverdin and bilirubin, are actually pigments that are naturally produced when the blood is broken down. When a bruise turns yellow, it’s because more bilirubin is responsible for breaking down the blood, and when it turns green, that’s what biliverdin does.

  • Why are my bruises so hard?

    A severe bruise, also called a hematoma, can occur after a more serious injury. In addition to the discoloration associated with bruising, a hematoma can cause the area to feel hard or firm to the touch.