A bruise, also called a contusion (kun-TOO-zhen), happens when a part of the body is injured and blood from the damaged capillaries (small blood vessels) leaks out. With no place to go, the blood gets trapped under the skin, forming a red or purplish mark that's tender to the touch — a bruise.
Many things can cause a bruise, but most happen when we bump into things — or things bump into us.
Anyone can get a bruise. Some people bruise easily, while others don't. Bruising depends on several things, such as:
how tough the skin tissue is
whether someone has certain diseases or conditions
whether a person's taking certain medicines
Also, blood vessels tend to become fragile as we age, which is why older people tend to bruise more easily.
How Long Do Bruises Last?
Bruises usually fade away in about 2 weeks. Over that time, the bruise changes color as the body breaks down and reabsorbs the blood. The color of the bruise gives an idea of how old it is:
When a bruise first happens, it's looks reddish as the blood appears under the skin.
Within 1–2 days, the in the blood changes and the bruise looks bluish-purple or even black.
After 5–10 days, the bruise looks green or yellow.
Then, after 10–14 days, it turns yellow-brown or light brown.
Finally, the bruise fades away.
How Can Parents Help?
It takes time for bruises to get better, but you can help your child feel better while one heals. Try these tips:
Apply a cold compress. Wrap a towel around a cold pack, bag of ice, or bag of frozen vegetables and place it on the injury. This can help keep the amount of bruising and swelling small by slowing the blood flow to the injured spot. Apply cold to the bruise for 15–20 minutes 3–4 times a day for a day or two after the bruise first appears
Raise the bruised area. To reduce swelling and bruising, raise the bruised area above the level of your child's heart. To do this, rest and prop the bruised area up on pillows, if possible.
Pain medicine might help. Give acetaminophen for pain, if needed.
Wrap the bruise. If the bruise is swollen, it may help to wrap it loosely with an elastic bandage to give some support.
After 2 days, warmth may aid healing. A heating pad or warm washcloth wrapped in a towel can help some bruises heal. Even a warm bath can soothe sore areas. Warmth brings more blood flow to an area of the body, which can help as the body tries to heal the injury. Talk to your doctor to make sure heat is OK for your child's injury and don’t use heat in the first 48 hours of an injury because that can make the bruising bigger.
When Should I Call the Doctor?
Minor bruises are easily treated, but it's probably best to talk to a doctor if your child has a bruise that:
isn't improving after 2 weeks
is swelling and very painful
is near the eye and your child has trouble moving their eyes or seeing
Also call if:
Your child bruises often or gets bruises for no clear reason.
Your child can't move a joint or you think they may have a broken bone.
Can Bruises Be Prevented?
Bruises are hard to avoid completely. But when kids play sports, ride bikes, and do other things where they might bump, crash, or smash into something, they should wear protective gear like pads, shin guards, and helmets.