From the Research
Petechiae and ecchymoses are distinct types of skin discolorations caused by bleeding under the skin, differing primarily in size and appearance, with petechiae being tiny, pinpoint spots and ecchymoses being larger patches of discoloration. The key differences between petechiae and ecchymoses can be understood by considering the size, cause, and appearance of these skin lesions. Petechiae are tiny, pinpoint red or purple spots, typically measuring 1-2 millimeters in diameter, that occur when small blood vessels called capillaries break and leak small amounts of blood into the skin 1. They do not blanch (fade) when pressure is applied and are often found in clusters. In contrast, ecchymoses, commonly known as bruises, are larger patches of discoloration, measuring greater than 1 centimeter, that appear blue, purple, or black initially and change to green, yellow, and brown as they heal over days to weeks 2. Ecchymoses result from more significant bleeding into the skin and deeper tissues, often due to trauma that damages larger blood vessels.
Some of the key factors to consider when differentiating between petechiae and ecchymoses include:
- Size: Petechiae are smaller than ecchymoses
- Cause: Petechiae often result from capillary damage, while ecchymoses result from larger vessel damage
- Appearance: Petechiae are pinpoint spots, while ecchymoses are larger patches of discoloration
- Trauma: Ecchymoses are often associated with trauma, while petechiae may occur spontaneously
While petechiae may indicate serious conditions like platelet disorders, infections, or vasculitis, ecchymoses frequently result from everyday injuries, though they can also signal bleeding disorders when appearing without trauma 3. Both can be concerning when they appear spontaneously or in unusual patterns, particularly in patients taking anticoagulants or those with potential bleeding disorders. A thorough understanding of these differences is crucial for accurate diagnosis and management, as highlighted in recent studies 2, 1.