There are always inexplicable bruises on my body. What kind of inexplicable physical phenomenon is this?

Review expert: Zhang Yuhong, chief physician of the Department of Dermatology, Zhengzhou Central Hospital Affiliated to Zhengzhou University

Have you noticed a strange phenomenon: girls seem to have more bruises than boys, and they are always in different colors. Why is this? Shouldn't active boys be more likely to get hurt than girls?

1

Why are girls more likely to bruise?

To answer this question, we must first understand how bruises are formed.

Bruise is redness and swelling caused by subcutaneous bleeding . There are many capillaries under our skin. As their name suggests, capillaries are the smallest and most widely distributed blood vessels, with a diameter of only 6-9 microns (μm), while the diameter of a male hair is about 80 microns. They connect arterioles and venules, with thin walls and strong permeability.

Capillaries source: pixabay

Because capillaries are relatively fragile, a minor bump can cause them to rupture. At this time, the platelets and coagulation factors in the blood will stick together and block the blood vessels, but some blood will still seep into the subcutaneous tissue from the rupture and form a bruise.

The appearance of bruises is related to many factors, such as external impact, thin skin thickness, hormone conditions, etc.

Girls have more bruises than boys, and the main reason is that women have thinner skin. Girls have thinner skin, and with the same degree of bumps, their capillaries are more likely to rupture than boys. The oozing blood will be more obvious when it reaches the subcutaneous tissue, thus forming bruises. Men secrete more male hormones, so their skin is much thicker than women's , which can better protect their capillaries from damage, so bruises are less likely to occur.

Source: pixabay

Secondly, estrogen, as a vasodilator, can cause capillary dilation , and to a certain extent prevent the repair of capillaries after rupture, and also inhibit the aggregation of platelets. This will cause more blood to flow out of the capillaries before they are repaired, and will also cause girls' wounds to heal more slowly than boys , and the time required for bruises to disappear is longer than that of boys.

2

Why do bruises come in different colors?

The word "bruise" sounds like it should be blue, but in fact we will see bruises of various colors after the skin is bumped. This is because when the human body is repairing damaged capillaries, the color of the bruise will change accordingly over time.

When a blood vessel is just damaged, the blood that seeps out is fresh, and the oxygen-rich blood will appear red , and the bruise will be purple-red at this time.

After a few hours after the injury, the blood will darken and turn black-blue as it coagulates and the oxygen in it slowly disappears .

But sometimes, you may find that the initial color of the bruise is blue. This is because the bruise is deeper and farther away from the skin, and the blood leaking from the capillaries has consumed all the oxygen when it goes from the deep to the surface of the skin .

Bruises of different colors Source: Ivy League Health Network

The bruise will then turn green. As the capillary wound begins to heal, macrophages will eat up the red blood cells that died due to lack of oxygen. At this time, heme, a component of hemoglobin , will be oxidized to biliverdin, a dark green substance that makes the bruise appear green. Biliverdin will continue to metabolize to bilirubin, which will make the bruise look yellowish. Then the yellow will become lighter and lighter until it disappears, and the bruise will be completely healed.

3

Are bruises dangerous?

"Bruise and purple" is actually a normal physiological phenomenon. If you occasionally find bruises on your body, you don't have to worry too much, because bumps and bruises in daily life are inevitable. But if you often have bruises on your body for unknown reasons, then you should pay attention to it.

For example, a decrease in platelets can cause bruises on the skin, and thrombocytopenic purpura is a disease caused by a decrease in platelets that causes increased bruises. In addition, hemophilia and von Willebrand disease are also blood diseases that are prone to bruises. In addition, a lack of vitamins C and K , or taking some special anticoagulant drugs can also cause abnormal coagulation function in the body, resulting in unexplained bruises.

Generally speaking, bruises will fade in one to two weeks. But if you want to make bruises heal faster, there are actually some simple and useful methods. The first is to apply ice. Within 48 hours of the bruise , you can soak a towel in cold water for a while and then apply it to the injured area. This can effectively reduce the amount of bleeding from the wound and greatly reduce the degree of bruising.

Ice source: pixabay

After 48 hours, you can use hot compresses . Hot compresses can promote blood circulation and eliminate blood stasis. You can use a hot water bottle or hot towel to apply heat to the affected area, which will help dissipate bruises. However, the temperature should not be too high or the time should not be too long, otherwise it will easily cause skin burns. Secondly, when you just bump into something, you can raise the injured part as high as possible above the heart , which can reduce capillary bleeding to a certain extent.