A contusion represents hemorrhage or bleeding into the skin and is secondary to blunt trauma. When a contusion is diffuse, it is referred to as bruise. When a contusion is focal it is a hematoma. The accuracy of utilization of alternate light source (ALS) to diagnose bruising is an area of research for our expert.
A laceration represents tearing of the skin secondary to crushing, cutting, or shearing forces. An abrasion, or “scrape,” is removal of superficial skin layers secondary to friction.
Petechiae are skin finding secondary to small broken blood vessels (capillaries) in the skin. These can be caused by abuse secondary to compressive injuries, but also occur from non-abusive causes such as some accidents, coughing, vomiting, infection and bleeding disorders.
Small children who do not move (immobile) rarely sustain bruises. When children become mobile, the most common locations for accidental bruising include the anterior tibia or knee, followed by the forehead, scalp, and upper leg. In general, accidental bruising in mobile kids most commonly occurs over bony prominences. Bruising in protected areas of the body, such as hands, ears, neck, buttocks, medial and posterior thighs, and upper arms, should raise concern for physical abuse.
There are clearly identifiable patterns of injury that may be evident while examining a child. In identifying a pattern, it is important to work closely with the investigative team working on the case. Not all pattern bruises are abuse – as accidental mechanisms can also product “patterns”; and some skin findings perceived to be bruises may be other skin conditions.
The visual appearance of a bruise depends on site of injury, depth of tissue, skin complexion, age, and characteristics of each individual’s inherent healing capabilities. Dating by visual inspection has been demonstrated to be inexact and should not be relied upon to accurately identify timing of an injury.