Look a little closer
A bruise changes from purple toward green and yellow because blood trapped under intact skin is being broken down and cleared. An impact damages small vessels, allowing red cells and fluid to enter surrounding tissue without necessarily cutting the surface.
Early color reflects oxygenated and deoxygenated hemoglobin together with bruise depth, skin tone and lighting. It may appear red, blue or purple. Real bruises do not follow one exact color timetable, and appearances vary widely among people and body sites.
Immune cells remove damaged red blood cells and dismantle hemoglobin in stages. The pathway can produce green biliverdin, followed by yellow bilirubin and other breakdown products.
As products leave through blood and lymph and iron is recovered, the discoloration fades. Small bruises commonly resolve on their own, but size, depth, circulation, age and medications influence the time required.
Color alone cannot reliably date an injury. Bruises caused at the same time can look different, and several colors may coexist in one area. Forensic assessment therefore should not assign a precise age from color by itself.
Large unexplained or frequent bruises, severe swelling, significant pain or other bleeding deserve medical evaluation. In an ordinary bruise, the shifting palette is a visible trace of the body dismantling and recycling leaked blood.
