Most bruises are nothing to worry about and will heal within weeks or months. They can vary in color, and skin color may affect the appearance of a bruise.

However, random, sporadic bruising may be a symptom of something less obvious, especially if there are other symptoms. Bruises on the torso, back, or face could be a concern.

Here are some key factors in random bruising:

• Age: Older adults are much more susceptible to bruising. The skin becomes thinner and less flexible, especially on the backs of the arms. Blood vessels lose elasticity and break much more easily.
• Genetics: A tendency to bruise easily can run in the family. For example, von Willebrand’s disease is a hereditary bleeding disorder in which the blood does not clot properly. This leads to easy bruising or larger bruises. However, it only affects up to 1% of the United States population.

Unexplained bruising is very common and heals relatively quickly. However, if a bruise persists, changes in size, or looks unusual, there may be an underlying condition or other factors.

The following are some possible causes of random bruising.

Medications and supplements

Medications such as anticoagulants, nonsteroidal anti-inflammatory drugs (NSAIDs), and corticosteroids reduce the blood’s ability to clot. This may result in blood leaking from vessels and accumulating under the skin.

Someone who takes medication and has random bruising should speak to a doctor for advice and to discuss their drug and family medical history.

A bleeding or clotting disorder

Underlying bleeding disorders — such as hemophilia, thrombocytopenia, or factor V deficiency — can cause bruising.

Hemophilia is a rare genetic condition in which people lack either clotting factor VIII or IX, resulting in excessive bruising.

People with immune thrombocytopenia have a low platelet count, and bruising can also appear for no reason. Platelets are cells that help the blood to clot and stop bleeding.

Factor V deficiency is a rare bleeding disorder in which people lack the coagulation protein factor V, which prevents blood from clotting. Symptoms can occur at any age, but most severe cases occur during childhood.

Other common symptoms of a bleeding disorder include:

• nosebleeds
• blood in the urine or stool
• bleeding gums

Infection

Sepsis is an infection that causes a buildup of toxins in the blood or tissues. People with sepsis may develop a cluster of tiny blood spots, resembling pinpricks in the skin (petechiae) or purple areas (purpura). Without treatment, these may increase, join together, and form larger bruises.

Also known as blood poisoning, sepsis requires immediate emergency treatment.

Vitamin deficiencies

A poor diet can negatively affect health, and vitamin deficiencies can contribute to random bruising.

Some deficiencies include vitamin C deficiency and vitamin K deficiency.

Vitamin C is versatile and vital to health. It is necessary for collagen production, boosts the immune system, and maintains antioxidant activity. It also eliminates harmful free radicals that can lead to tissue degeneration and random bruising.

The result of extreme vitamin C deficiency is scurvy, which also leads to bleeding gums, fingernail and tooth loss, and heart failure.

Meanwhile, vitamin K deficiency can contributeTrusted Source to significant bleeding, issues with bone development, and cardiovascular disease. It is rare in adults and generally occurs in the neonatal period.

However, taking anticoagulants and antibiotics that interfere with vitamin K production may cause deficiencies.

People can prevent vitamin deficiencies by making dietary changes and taking supplements.

Liver or kidney disease

When the liver experiences damage, it stops producing the proteins required for blood clotting. Cirrhosis, for example, is the result of continuous long-term damage, and bruising easily is a symptom.

However, it may appear alongside fatigue, appetite loss, abdominal pain, and nausea. A person with kidney disease may also bruise easily due to a loss of skin elasticity.

Medications for treating liver or kidney disease can also hinder the blood clotting process and inhibit platelet function. Ecchymosis, which occurs when blood leaks from a broken capillary into surrounding tissue, is common and requires a preventive treatment plan.

Anyone who suspects liver or kidney disease should consult a doctor.

Other causes

Cancer treatments, such as chemotherapy and targeted therapy, may also lead to bruising. This is because they lower the amount of platelets in the blood.

Easy bruising and bleeding are common leukemia symptoms. They generally affect the back, legs, and hands. Another indication of possible leukemia is lots of bruises with no indication as to a cause. Bruises that take longer than usual to disappear are another concern.

Bernard-Soulier syndrome is a rare, inherited blood clotting disorder. People with this condition may bruise easily, bleeding from small blood vessels under the skin.

Doctors will check a woman’s platelet levels throughout pregnancy, but bruising could be a symptom of gestational thrombocytopenia, which can lead to a low platelet count.

Always mention any unusual bruising during pregnancy to a doctor or midwife.

It is impossible to completely prevent bruising. Although bruises are usually harmless, they can sometimes indicate a medical condition that requires treatment.

For example, a person should see a doctor if:

• bruising occurs for no apparent reason and does not heal within a few weeks
• bruises appear in unusual locations, such as the torso, back, or face
• there are several bruises in one specific area or a cluster scattered on different parts of the body
• there are recurring bruises
• bruising appears with other symptoms, such as fatigue, nausea, or a high temperature

Why might a person get random bruises for no reason?

Bruises may result from underlying medical conditions, age as the skin becomes thinner, or genetics. Many bruises may also result from knocks against objects and usually fade within a few weeks.

What kind of bruising should a person worry about?

A person should speak with a doctor if they have continuous bruising with no apparent reason, bruises in certain locations such as the torso, or they appear alongside other symptoms such as fatigue and nausea.

What deficiencies can cause random bruising?

Deficiencies that may cause random bruising include vitamin C deficiency and vitamin K deficiency.

Occasional bruising is rarely a cause for concern. However, it is worth talking with a doctor if the discoloration does not heal within a few weeks. There may be a blood clotting issue or another underlying condition that needs treatment.

Taking certain medications and growing older can be the root of the problem. However, further investigation may be necessary if a person experiences other symptoms alongside random bruising.