Purpura is purple-colored spots and patches that occur on the skin, and in mucus membranes, including the lining of the mouth.
Blood spots; Skin hemorrhages
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 normal platelet counts (non-thrombocytopenic purpuras) or low platelet counts (thrombocytopenic purpuras).
Non-thrombocytopenic purpuras may be due to:
- Blood clotting disorders
- Congenital cytomegalovirus
- Congenital rubella syndrome
- Drugs that affect platelet function
- Fragile blood vessels seen in older people (senile purpura)
- Inflammation of the blood vessels (vasculitis), such as Henoch-Schönlein purpura, which causes a raised type of purpura
- Pressure changes that occur during vaginal childbirth
- Scurvy (vitamin C deficiency)
- Steroid use
- Certain infections
Thrombocytopenic purpura may be due to:
- Drugs that reduce the platelet count
- Idiopathic thrombocytopenic purpura (ITP)
- Immune neonatal thrombocytopenia (can occur in infants whose mothers have ITP)
- Meningococcemia, a raised type of purpura
When to Contact a Medical Professional
Call your health care provider for an appointment if you have signs of purpura.
What to Expect at Your Office Visit
The provider will examine your skin and ask about your medical history and symptoms, including:
- Is this the first time you have had such spots?
- When did they develop?
- What color are they?
- Do they look like bruises?
- What medicines do you take?
- What other medical problems have you had?
- Does anyone in your family have similar spots?
- What other symptoms do you have?
A skin biopsy may be done. Blood tests may be ordered to determine the cause of the purpura.
Marks JG, Miller JJ. Purpura. In: Marks JG, Miller JJ, eds. Lookingbill and Marks' Principles of Dermatology. 5th ed. Philadelphia, PA: Elsevier Saunders; 2013:chap 17.
Reviewed By: Kevin Berman, MD, PhD, Atlanta Center for Dermatologic Disease, Atlanta, GA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.