What is the definition of petechiae?

Petechiae are defined as small, pinpoint-sized red or purple spots that appear on the skin or mucous membranes. They are the result of minor bleeding from capillaries, which can be due to various underlying conditions such as thrombocytopenia (low platelet count), blood clotting disorders, or local trauma.

Identifying petechiae is important in clinical practice, as their presence can indicate a more serious systemic condition or a localized issue requiring further investigation. Unlike larger red or purple spots, which are referred to as purpura or ecchymoses depending on their size and cause, petechiae are specifically characterized by their small size and distinct appearance. Thus, this definition provides clarity on identifying and understanding the clinical significance of these spots in a patient.