Healthy kids are active, and active kids get bruises. Bruising on the lower legs is very common, especially here in South Florida, where kids live in shorts year-round. But when should parents become concerned about their kids’ bruises?
A bruise is a collection of blood beneath the skin, caused by blood leaking from blood vessels. These leaks — and all bleeding, from bruises to nosebleeds — are stopped in three steps.
▪ The first step occurs when the blood vessel tries to squeeze shut to close the leak; this sends chemical signals that direct the next two steps.
▪ In step two, platelets — tiny sticky pieces of cells that float in the blood that easily stick together, but can pull apart — travel to the hole in the blood vessel, where they stick to each other to make a delicate clot. The clot needs a glue or cement to make it tight and strong enough to stop the bleeding.
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▪ This cement, called fibrin, is formed in step three by the action of proteins known as clotting factors.
After these three steps, the bleeding stops because the hole is plugged. All of this takes less than a minute, and the resulting bruise or scab you see on your child’s knee is made of platelets and the fibrin glue.
Bruising because of accidental injury is common by the time a child is a year old. Normal bruising is usually limited to arms and legs, particularly the front part of the legs. The bruising is flat and occurs as a result of some sort of trauma, and is not associated with widespread, lumpy bruises or scattered pinpoint red spots.
If you are worried that your child may be bruising too much, a visit to the pediatrician is in order. The physician will take a good history. The doctor will also look to see if your child has any other red skin lesions or spots in his/her mouth or nose, which could suggest inherited blood vessel overgrowth syndromes. The pediatrician will determine if your child seems unusually pale, a possible sign of blood loss or underproduction of red blood cells.
Your doctor might ask if your child has been limping, overly tired or less hungry or active than usual. These symptoms often bring to mind a parent’s greatest fear — leukemia or another cancer. While unusual bruising can be associated with these serious diagnoses, rest assured, pediatric cancer is very rare.
Any recent infection can cause a person to make antibodies that temporarily destroy platelets, leaving a child with too few platelets to make that first clot. In addition, knowing how old a bruise is might help you or your child recall a specific injury that would explain the bruise’s existence.
Some medications like aspirin or Motrin, when taken in excess, might interfere with how well platelets stick together. Even health food supplements, like fish oil, gingko or turmeric, can disrupt platelet function. It’s also important to consider if family members, including cousins, aunts, uncles and grandparents, have easy bruising or other bleeding symptoms.
People with inherited problems of the skin or the supporting tissues — cartilage and collagen — can bruise easily. Your child may need to have some bloodwork done to see if he or she makes enough platelets and also to measure how long it takes for a clot to be formed. Abnormal results might suggest a platelet disorder or the possibility of a mild problem with clotting.
If your pediatrician thinks that the bruising is not normal, you should be referred to a pediatric hematologist, who specializes in coagulation disorders. The hematologist will repeat all the questions and the physical exam, while asking more questions and recommending additional screening tests. From that, the hematologist will determine the likelihood of your child's bruising being the result of a medication effect, an inherited platelet/factor disorder or potentially more serious conditions.
Most bruising that occurs in children is perfectly normal, even if it looks awful to mom and dad. There is usually nothing that needs to be done except wait for the bruise to fade, but if you’re concerned, don’t be afraid to ask questions. After all, healthy children are everyone’s goal.
Dr. Fernando F. Corrales-Medina is an assistant professor and Dr, Joanna A. Davis is an associate professor in the Pediatric Comprehensive Hemophilia Treatment Center, Division of Pediatric Hematology/Oncology at UHealth – University of Miami Health System. For more information, visit UHealthSystem.com/patients/pediatrics.