Kids’ Health: Causes of Abnormal Bruising

Getting an occasional bruise is a pretty normal part of life; either from hitting your shin on the coffee table or colliding with someone while playing sports, bruises are a natural reaction to physical trauma. Bruises are also a very normal part of growing up, and kids are just as likely (or maybe sometimes even more likely) to get a bump from time to time. Sometimes, though, it may seem like a child bruises more easily than other kids. All bodies react slightly differently to different circumstances, but bruising easily can be a sign of other problems.

What is a Bruise?

A bruise is a type of hematoma, the medical term for the localized bleeding that can occur after the body is subjected to an accidental injury or other trauma. Also known as a contusion (or ecchymosis), a bruise is typically identified by visible blue, red, or black discoloration on the surface of the skin. Yet a bruise can actually happen anywhere on the body where blood vessels exist, including organs, muscles, and even bones. Though bruises are generally not serious, the severity and location of the bruise can potentially lead to a more involved medical condition.

When the body experiences a physical trauma—say bumping into a table with your arm, for example—the tiny blood vessels (known as capillaries) under your skin are ruptured. These ruptures cause blood from the vessels to seep into the surrounding tissue; a larger trauma causes more vessels to break and a smaller trauma causes fewer to break. A bruise forms when enough blood collects in the area to be visible through the skin. Though the bleeding won’t be visible, the same principle applies to a trauma that injures an area of the body that isn’t just under the skin.

In some cases, when the trauma is severe enough, enough blood will pool in the area and cause a visible lump; even though “hematoma” is an umbrella term for all such injuries, this kind of lump is usually what people mean when they say hematoma. For the most part, bruises are a minor annoyance that goes away on its own after a few days. For some adults and children, though, bruising can happen much more easily; the same intensity bump that causes a bruise on one child might cause no discernable bruise at all on another child.

Bruise Colors and Types to Watch Out For

When a child (or anyone) gets a bruise, it tends to follow a typical progression. Most bruises aren’t even visible right after trauma takes place; if anything, the area of skin may have a reddish color. It usually isn’t until the next day or the day after when discoloration begins to show; at that point, depending on the intensity of the impact, the bruise may be purple, blue, or even nearly black. These colors are visible because hemoglobin in the blood has lost oxygen and changed color.

While bodies react in different ways, the dark colors from the initial impact will start to fade approximately 5-10 days later. At that point, the color changes to a yellow or greenish color; this change occurs because the body’s repair mechanisms begin to break down the hemoglobin and other damaged cells and carry them off to be disposed of. Eventually, the bruised area will gradually return to the normal skin color.

Bruising that follows the above progression should be regarded as a normal, healthy response to an injury; the changing colors are an indication that the body is healing as it should. There are, however, other signs and red flags related to bruising that parents should watch out for that may require medical attention or point to an underlying problem:

• disproportional bruising (a large bruise after a minor trauma)
• bruises that can’t be explained by actual trauma
• bruises that last longer than a couple weeks
• nosebleeds that last longer than 10 minutes and don’t respond to pressure
• excessive bleeding after surgery, dental work, or another minor procedure
• bruises on young children before they learn to crawl or walk
• bruising in unusual places (chest, back, face, ears, etc.)

Causes of Abnormal Bruising in Children

The vast majority of kids will get an occasional bruise just from playing outside or with friends, and it won’t be a cause for concern. When abnormal bruising occurs, either in an area where there was no trauma or when a bruise appears quickly after a minor trauma, it can point to other conditions:

• Hemophilia (or haemophilia): This condition is an inherited genetic disorder that disrupts the body’s ability to form blood clots after an injury. It has two main types—hemophilia A (factor VIII deficiency) and hemophilia B (factor IX deficiency)—that affect different blood proteins involved in clotting. People with hemophilia tend to bruise easily because the localized bleeding takes less force to cause and won’t stop bleeding as easily.
• Anemia: Anemia is the term for a decrease in the amount of red blood cells or hemoglobin in the blood. In addition to a variety of other symptoms, the typical iron deficiency associated with anemia can cause blood to hold less oxygen and the skin to be more susceptible to bruising.
• Vitamin K Deficiency: The body uses vitamin K to create proteins that are important in blood clotting. A deficiency in vitamin K, then, can cause bruising in a similar way as hemophilia.
• Von Willebrand Disease: This relatively common bleeding disorder is a genetically inherited condition that can cause excessive bleeding and easy bruising.
• Thrombocytopenia: This complicated-sounding name is the term for having an abnormally low platelet count in the blood. Since platelets are a key factor in blood clotting, a low platelet count can lead to excess bleeding as well as easy bruising.
• Leukemia (or leukaemia): Leukemia is a type of blood cancer that originates in bone marrow and can cause large quantities of abnormal blood cells in the body. In addition to symptoms related to cancer, leukemia can cause bruising, bleeding, and a higher risk of infection.
• Medication: Some medications, like aspirin or antibiotics, can make the body more susceptible to bruising.
• Idiopathic Thrombocytopenic Purpura (ITP): ITP is an autoimmune disorder that causes antibodies to attack and break down platelets in the blood. One of the telltale signs of ITP is a bruise-like rash (purpura) or small spots (petechiae) from bleeding under the skin.
• Henoch-Schonlein Purpura (HSP): Similar to ITP, HSP is a skin disease that causes small, red bruises that also indicate subdermal bleeding.

When to Contact a Doctor

As noted above, most bruises on most kids are not a cause for concern; it’s perfectly normal for a child to get small bruises from physical play. Unless there is an indication that the trauma was especially intense, such bruises will heal on their own. If your child bruises especially easy, the bruise hangs around for more than a couple weeks, or if the child seems to bleed excessively even with minor scrapes, there may be another underlying condition at work.

TrustCare Kids is TrustCare’s special clinic designed to diagnose and treat kids as quickly and conveniently as possible. If your child is prone to bruising or bleeding, you can bring him or her to the kids’ clinic for fast and friendly treatment. If you need urgent care, you can stop by for a walk-in visit, or contact us to schedule a primary care pediatrician appointment.

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This post has been medically reviewed by Dr. Catherine Phillippi, pediatrician at TrustCare Kids. She earned her medical degree from the University of Mississippi School of Medicine in 1999 and completed her pediatric training at the University of Arkansas for Medical Sciences/Arkansas Children’s Hospital.