Purpura is purple-colored spots and patches that occur on the skin, and in mucus membranes, including the lining of the mouth.
Alternative Names
Blood spots; Skin hemorrhages
Considerations
Purpura occurs when small blood vessels leak blood under the skin.
Purpura measure between 4 and 10 mm (millimeters) in diameter. When purpura spots are less than 4 mm in diameter, they are called petechiae. Purpura spots larger than 1 cm (centimeter) are called ecchymoses.
Platelets help the blood clot. A person with purpura may have a normal platelet count (non-thrombocytopenic purpuras) or a low platelet counts (thrombocytopenic purpuras).
Causes
Non-thrombocytopenic purpuras may be due to:
Amyloidosis (disorder in which abnormal proteins build up in tissues and organs)
Blood clotting disorders
Congenital cytomegalovirus (condition in which an infant is infected with a virus called cytomegalovirus before birth)
Kitchens CS. Purpura and other hematovascular disorders. In: Kitchens CS, Kessler CM, Konkle BA, Streiff MB, Garcia DA, eds. Consultative Hemostasis and Thrombosis. 4th ed. Philadelphia, PA: Elsevier; 2019:chap 10.
Review Date:
6/7/2023
Reviewed By:
Elika Hoss, MD, Assistant Professor of Dermatology, Mayo Clinic, Scottsdale, AZ. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.