A bruise is a mark on your skin. 

A bruise is a mark on your skin. 


A bruise is a mark on your skin. Scientists call it a contusion. 



A bruise is a type of internal bleeding called a contusion. 

There is a specific way a bruise works inside your body. First, the damaged capillary endothelium releases a hormone called endothelin. This hormone narrows the blood vessel to help stop the bleeding. Next, the broken vessel exposes a factor called von Willebrand factor. This helps start coagulation, which is the way your body makes a clot. This clot acts like a plug for the wound.
Scientists use different names to describe different kinds of marks. A bruise is a type of hematoma, which is a collection of blood. Small marks under 3 millimetres are called petechia. Marks between 3 and 10 millimetres are called purpura. If a mark is 1 centimetre or larger, it is called an ecchymosis. 
Bruises can look many different colors as they change. At first, they might look red, blue, or almost black. This depends on if broken venules or arterioles caused the leak. 

Many things can change how a bruise looks or feels. For example, females may bruise more because they have more subcutaneous fat. Elderly people often bruise easily because their skin is thinner. Even your genes can matter, as natural redheads may bruise more easily. 

A bruise, scientifically known as a contusion, is a specific type of hematoma. A hematoma is a collection of blood that has pooled inside your body's tissues. 
When a bruise forms, your body immediately begins a complex biological response. The damaged capillary endothelium, which is the inner lining of the vessel, releases a hormone called endothelin. This hormone causes the blood vessel to narrow to minimize further bleeding. As the endothelium is destroyed, a substance called von Willebrand factor is exposed. This factor initiates coagulation, which is the process of forming a blood clot. This clot acts as a temporary plug to seal the damaged vessel.
Medical professionals use specific terms to categorize different types of skin discoloration based on size. Small spots called petechiae are less than 3 millimetres in diameter. These can result from many causes, such as straining, asphyxiation, or reactions to medications like warfarin. Larger marks between 3 and 10 millimetres are called purpura. 
The changing colors of a bruise are a visual map of how your body breaks down blood. This process involves the sequential degradation of hemoglobin, which is the protein in red blood cells. Initially, the bruise may appear red, blue, or almost black. This color depends on whether broken venules or arterioles caused the leak. 

Several biological factors influence how easily or severely a person bruises. Age is a major factor, as elderly skin is often thinner and less elastic. Gender also plays a role, as females may experience more bruising due to increased subcutaneous fat. Even genetics can be a factor; for instance, natural redheads may bruise more visibly. 
While many bruises are minor, some can be life-threatening and are measured using a harm score from 0 to 5. A score of 0 represents a light bruise with no damage, while a score of 5 is a critical bruise that carries a risk of death. 
Understanding the context of a bruise is vital for medical diagnosis. For instance, bruising around the navel combined with severe abdominal pain may suggest acute pancreatitis. Unexplained bruising can also be a warning sign for various medical conditions, including leukemia, meningococcal infection, or clotting disorders. 
🖼️ Images & Media (6)
More to explore
✨ What else?
Related topics you might enjoy
What is Nepedia?
A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.