Petechia

Overview
A petechia, plural petechiae is a small red or purple spot on the body, caused by a minor hemorrhage (broken capillary blood vessels).

Differential diagnosis of causes of petechia

 * Bolivian hemorrhagic fever
 * Boutonneuse fever
 * Crimean-Congo hemorrhagic fever
 * Congenital syphilis
 * Dengue fever
 * Duke's disease
 * Ebola
 * Endocarditis
 * Erythroblastosis fetalis
 * Gua Sha
 * Henoch-Schönlein purpura
 * Leukemia
 * Childhood protein-energy malnutrition such as Kwashiorkor or Marasmus
 * Typhus
 * Scarlet Fever
 * Schamberg's Disease
 * Kawasaki disease
 * Kawasaki fever
 * Rocky mountain spotted fever

Petechiae may be a sign of thrombocytopenia (low platelet counts). They also occur in circumstances when platelet function is inhibited (e.g., as a side effect of medications or during certain infections) or when excessive pressure is applied to tissue (e.g., when a tourniquet is applied to an extremity or with excessive coughing).

Petechiae should always be quickly investigated. They can be interpreted as vasculitis, an inflammation of the blood vessels, which requires immediate treatment to prevent permanent damage. Some malignancies can also cause petechiae to appear. Petechiae should be investigated by a physician immediately to rule out the more dangerous conditions. Dermatologists can be the most helpful specialists in these conditions because they can more easily identify if the condition is petechiae or some similar looking but less worrisome rash.

The significance of petechiae in children depends on the clinical context in which they arise. Petechiae in children can occur with viral infections. In this setting they do not necessarily signify serious illness. They are the hallmark of some possibly serious illnesses, however, such as meningococcemia, various causes of thrombocytopenia, and leukemia. Therefore, their presence should not be ignored.

Pathology / Forensics
Petechiae on the face and conjunctiva (eyes) are a sign of a death by asphyxiation. They are thought to result from an increase of pressure in the veins of the head and hypoxic damage to endothelial of blood vessels.