Petechia

A petechia (; pl.: petechiae) is a small red or purple spot (< 3 mm in diameter) that can appear on the skin, conjunctiva, retina, and mucous membranes which is caused by haemorrhage of capillaries. The word is derived from Italian petecchia'freckle', of obscure origin. It refers to one of the three descriptive types of hematoma differentiated by size, the other two being ecchymosis (> 1 cm in diameter) and purpura (3 to 10 mm in diameter). The term is typically used in the plural (petechiae), since a single petechia is seldom noticed or significant.

Petechiae can be caused by a number of infectious or noninfectious conditions, or by physical trauma. The presence of petechiae in certain locations, such as the eyes or neck, are sometimes considered forensically significant, such as in cases of suspected strangulation.