Purpura is defined as a hemorrhage of blood into the skin or mucous membranes and is most commonly seen on dependent areas (i.e., the lower legs and ankles) (Fig. 27.11).

Purpuric skin is purple, violaceous, or dark red in color and is nonblanchable because blood is present outside of vessel walls.

In contrast, erythema is red in color and blanches on compression because blood remains within the vessels.

Purpuric lesions can be a sign or symptom of an underlying vascular disorder or systemic disease or can represent a “benign” variant.

Purpura is divided into nonpalpable (macular) and palpable (papular) categories. Nonpalpable purpuric lesions that are smaller than 3 mm in size are referred to as petechiae; those larger than 3 mm are called ecchymoses.