What does it mean if i have bruising?

Depends: Bruises are common natural reactions to injury. As you get older, they can occur after little or no injury on the arms because the sun has thinned the skin around the veins, making them fragile. Bruises that appear on their own for no reason can be a sign of a bleeding disorder or certain blood diseases; see your doctor.

Purple skin mark: A bruise is a leakage of blood from a skin vein. Most bruises are caused by trauma to the skin in otherwise healthy people. If there is no trauma, it can signify something wrong with the vein, or with the bloods ability to coagulate properly, and can signify a blood disorder like leukemia. Older peope get arm bruises, and even tearing of the skin, from thin, sun damaged skin.