These purple patches are often referred to as purpura and result from small blood vessels bursting and leaking blood under the skin. When blood collects beneath the skin, it creates the discolored patches that can range in size from small spots, known as petechiae, to larger areas, known as ecchymoses. The color can vary from red to purple and even dark blue, depending on how fresh the bleeding is and how close the blood is to the skin’s surface.
Purpura is typically caused by fragile blood vessels that are more prone to breakage, especially as skin and vascular health change with age. These patches are more common on areas like the forearms, where the skin is thinner and more exposed to potential injury.