By Vincent Iannelli, MD 

 Medically reviewed by Jenny Sweigard, MD

Kids seem to bruise easily. Whether it is a toddler taking their first steps or a preschooler who is rough-housing all of the time, kids are prone to bruises.

Many parents worry that bruising is a sign of a serious illness. Fortunately, most of the time, it is normal.

This article will explore the signs of normal and abnormal bruising and the possible causes.

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Signs of Normal Bruising and Bleeding

Normal bruising is usually found on a child's shins. That's because they often bump their lower legs against things as they walk or run.

These bruises are usually flat and smaller than the size of a quarter. Younger children often get bruises on their foreheads from falling and bumping their heads, too.

Frequent nosebleeds are another symptom that often prompts parents to think that their child has a bleeding disorder.

But unless young children have some of the additional signs listed below, nosebleeds are often normal and are often due to nose picking or dry air.1

Color Progression of Bruises

Typically the first sign of a bruise is a red spot. You may or may not notice this initial discoloration. Then, a day or so later, the deep purple or blue color commonly associated with bruising appears.

As the bruise heals, it turns to green, yellow, and possibly yellowish-brown before disappearing. The process can take up to two weeks.

If you notice bruises on your child that do not follow this typical pattern of color progression or do not heal, discuss it with your pediatrician.

Signs of Abnormal Bleeding or Bruising

Certain signs can indicate that your child's bruise is abnormal. The size and location of bruises or the time it takes for bleeding to stop can be red flags.

Some indications that bruising should be evaluated by a doctor include:

• Large bruises that are raised and seem out of proportion to the injury that caused it (for example, a huge bruise for a small bump against a table)

• Unexplained bruises that occur without any known fall or injury2

• Bruises that last more than a few weeks

• A family history of bleeding, easy bruising, or a bleeding disorder, such as von Willebrand disease or hemophilia, that is inherited

• A bloody nose, or epistaxis, that lasts longer than 10 minutes after proper treatment with direct pressure3

• Excessive bleeding after dental procedures or surgery

• Any bruises in infants who have not started to crawl or walk yet

• Bruises in unusual places, like a child's chest, back, hands, ear, face, or buttocks

Causes

As your toddler learns to walk, they will likely fall and bump into things a lot. Unfortunately, this may mean they get quite a few bruises along the way.

Older children tend to have bruises on their arms and legs from playing and being active. Bruises of this type are generally nothing to worry about.

Causes of bruising can include:

• Falls and injury: Not surprisingly, severe injuries can often lead to extensive bruising. Instead of simply looking at the size of a bruise, it is more important to think about whether or not the bruise is proportionate to the injury. You would expect a larger bruise if your child falls out of a tree than if they trip on grass.

• Child abuse: Bruising on infants, unexplained bruises, and bruises in unusual places (upper arms, hands, ears, neck, buttocks, etc.) are considered suspicious. Likewise, bruises in specific shapes, like a large bite mark, cigarette burn, or belt mark can be signs of child abuse.4

• Von Willebrand disease: This is a common and often mild genetic bleeding disorder. It can cause easy bruising, frequent nosebleeds, heavy menstrual bleeding, and bleeding after surgery.

• Thrombocytopenia: This is the medical name for a low count of platelets, which are important in helping blood to clot. A low platelet count can be caused when platelets aren't being produced, are being destroyed, or are contained in an enlarged spleen.

• Idiopathic thrombocytopenic purpura (ITP): In this autoimmune disorder, the body does not produce enough platelets. It is usually triggered by a recent viral infection, where young children develop large bruises and petechiae (small purple dots under the skin) after an illness.

• Henoch-Schonlein purpura (HSP): This immune disorder can cause abdominal pain, bloody stools, and joint pain. In addition, it produces a distinctive rash on a child's arms, legs, and buttocks that looks like bruises (purpura).

• Hemophilia A (factor VIII deficiency) or hemophilia B (factor IX deficiency): Hemophilia is usually diagnosed before a child is 2 to 5 years old. It may be suspected when a child has easy bruising, bleeding in joints, or excessive bleeding after a cut or dental procedure.

• Leukemia: These are cancers affecting blood cells. In addition to easy bruising, bleeding, and a low platelet count, children with leukemia usually have other signs and symptoms. They may have a low red blood cell count, fever, and weight loss.

• Vitamin K deficiency: Vitamin K1 or vitamin K2 are needed for blood clotting. Because of their essential role in producing prothrombin, a protein made by the liver that works to form blood clots, having a lack of either can lead to bleeding problems.5

• Side effects of certain medications: Aspirin, seizure medicines, and some antibiotics can cause abnormal bruising or bleeding.

Recap

Many things can cause bruises in children. Bumps and falls are the most common reason for bruising. But sometimes bruises can indicate something more serious, like child abuse, bleeding disorders, and certain cancers.

Tests

Most kids with normal bruising won't need any testing.

However, when bruises are large or are associated with other signs that might suggest a bleeding disorder, then testing might be needed.

Common tests for kids with bruising can include:

• Complete blood count (CBC): This common blood test measures and counts blood cells, including red blood cells, which carry oxygen through the body, and white blood cells, which are part of the immune system and help fight infections. It also looks at the number of platelets, which are important for clotting.

• Peripheral blood smear: This test looks at a child's blood under a microscope to check the quantity and quality of their blood cells.

• Prothrombin time (PT) and partial thromboplastin time (PTT): This measures how well blood is clotting. It can help determine whether a child could have a bleeding disorder, such as hemophilia.

• Factor VIII, factor IX, and factor XI: These specific blood clotting factors are missing or deficient in different types of hemophilia. These are proteins needed for the blood to clot.6

• Fibrinogen: This is another protein that helps blood clot. A deficiency will lead to prolonged bleeding. 

• Bleeding time: This test looks at how long it takes a child to stop bleeding.

• PFA-100 platelet function screen: This test evaluates how well platelets are working. It replaces the less-reliable bleeding time test in many labs.

• Ristocetin cofactor activity and von Willebrand antigen: These tests are used specifically to identify von Willebrand disease.7

Summary

Keep in mind that children bruise frequently. Most of the time, there's no need to worry. 

Even so, if your child has excessive bruising, easy bruising, or other signs of a bleeding disorder, it's important to talk to your pediatrician.

A thorough exam and testing can help your child's physician determine whether the bruising is something that requires treatment.

7 Sources

McGarry GW. Recurrent epistaxis in children. BMJ Clin Evid. 2013;2013:0311.

American Academy of Pediatrics, HealthyChildren. Bruises and cuts.

American Academy of Pediatrics, HealthyChildren. How to stop a nosebleed.

American Academy of Pediatrics, HealthyChildren. AAP offers guidance to pediatricians evaluating bruising or bleeding that is suspicious for abuse.

Centers for Disease Control and Prevention. What is vitamin K deficiency bleeding?

Centers for Disease Control and Prevention. Diagnosis of hemophilia.

Centers for Disease Control and Prevention. von Willebrand disease (VWD) diagnosis.

Additional Reading

Despotovic JM. Causes of thrombocytopenia in children.

Hoffman R, Benz EJ, Silberstein LE, Heslop H, Weitz J, Anastasi J. Hematology: Basic Principles and Practice, 6th ed. Elsevier; 2018. doi:10.1016/C2013-0-23355-9

Kliegman R,  Stanton B, St Gene J, Schor N, Behrman R. Nelson Textbook of Pediatrics. Edition 21. Philadelphia, PA: Elsevier

By Vincent Iannelli, MD
 Vincent Iannelli, MD, is a board-certified pediatrician and fellow of the American Academy of Pediatrics. Dr. Iannelli has cared for children for more than 20 years.