Purpura is purple-colored spots and patches that occur on the skin, on organs, and in mucous membranes, including the lining of the mouth.

Purpura occurs when small blood vessels under the skin leak.

When purpura spots are very small, they are called petechiae. Large purpura are called ecchymoses.

A person with purpura may have normal platelet counts (nonthrombocytopenic purpuras) or decreased platelet counts (thrombocytopenic purpuras). Platelets help the blood clot.

Nonthrombocytopenic purpuras may be due to:

• Drugs that affect platelet function
• Congenital cytomegalovirus
• Congenital rubella syndrome
• Fragile blood vessels (senile purpura)
• Pressure changes that occur during vaginal childbirth
• Vasculitis such as Henoch-Schonlein purpura

Thrombocytopenic purpura may be due to:

• Drugs that prevent platelets from forming
• Hemangioma
• Idiopathic thrombocytopenic purpura (ITP)
• Immune neonatal thrombocytopenia (can occur in infants whose mothers have ITP)
• Meningococcemia