What is the primary characteristic of petechiae?

The primary characteristic of petechiae is the appearance of tiny red spots on the skin. These spots are small and can resemble pinpoint-sized, flat, red or purple lesions. They occur due to the rupture of small blood vessels (capillaries) beneath the skin, which leads to tiny amounts of blood leaking into the surrounding tissue. Because of their size and distinct coloration, petechiae can be critical in medical assessments, as they are often associated with various medical conditions, including infections, clotting disorders, and other underlying health issues.

The other characteristics mentioned in the options, such as large bruises, dark spots, and white patches, do not accurately describe petechiae. Large bruises are generally larger areas of discoloration due to bleeding under the skin, while dark spots could refer to skin lesions or moles, and white patches may suggest conditions like vitiligo or fungal infections, none of which align with the definition and appearance of petechiae.