The small red or purple spots found in the skin or mucosal tissue are called petechiae. These spots are tiny, pinpoint-sized hemorrhages that occur due to the rupture of small blood vessels, causing blood to leak into the surrounding tissues. Petechiae can appear in clusters, resulting in a rash-like appearance, and may be associated with various conditions, ranging from minor injuries to more serious health issues like blood disorders or infections.
In contrast, cysts are closed sacs filled with fluid, air, or other materials that can occur in various parts of the body. Blisters are fluid-filled sacs that develop as a result of friction or irritation to the skin, while keloids are raised scars that form due to excessive collagen production during the wound healing process. Each of these conditions has distinct characteristics and causes, which differentiates them from the appearance and causes of petechiae.