Blue marks on the body — also known as bruises — are skin discolorations that occur when small blood vessels under the skin are damaged, causing blood to leak into the surrounding tissues.
What do they usually mean?
In most cases, they indicate:
1. A minor hit or injury, even one you may not remember.
2. Strong pressure on the skin, such as carrying something heavy.
3. Naturally fragile blood vessels in some people.
When are they normal?
After bumping into something or falling.
After a blood draw or injection.
In people with fair skin or sensitive vessels.
When can they indicate a health issue?
If the bruises appear:
Frequently and without a clear reason,
Very large or very painful,
Along with other bleeding (gums, nose, heavy periods),
they may be related to:
Vitamin deficiencies (like Vitamin C or K),
Blood clotting problems,
Blood-thinning medications,
Anemia or rare blood disorders (less common).
When to see a doctor immediately?
Sudden, widespread bruising.
Severe swelling or persistent pain.
Bruises on the abdomen or chest without injury.
If you are taking blood thinners.