Visualization of old bruises in children: Use of violet light to record long-term bruises

When a child consultation center evaluates abused children, evidence of the abuse must be documented. Children who have suffered physical abuse often have bruises, which cannot be confirmed by visualization when the bruise has healed. In forensics, a method to confirm an old bruise by ultraviolet radiation is possible. However, long-term ultraviolet exposure can be harmful. In this study, we observed 15 bruises on healthy volunteer children using four kinds of light sources, including ultraviolet radiation, over time. The violet light source enabled observation of a bruise for a longer time than ultraviolet radiation. Although other studies have shown that violet light is superior for enhancing bruises, this is the first report to evaluate data concerning the ability to identify bruises over time in living children. These results might help to identify evidence of past violence suffered by children.