Bruise colors vary from red, blue, or almost black, depending on the severity of broken capillaries or blood vessels within the bruise site. Broken venules or arterioles often result in a deep blue or dark red bruise, respectively. Darker colored bruises may result from a more severe bleeding from both blood vessels. Older bruises may appear yellow, green or brown. Cause
There are many causes of subcutaneous hematomas including ecchymoses. Coagulopathies such as Hemophilia A may cause ecchymosis formation in children. The medication betamethasone can have the adverse effect of causing ecchymosis.The presence of bruises may be seen in patients with platelet or coagulation disorders, or those who are being treated with an anticoagulant. Unexplained bruising may be a warning sign of child abuse, domestic abuse, or serious medical problems such as leukemia or meningoccocal infection. Unexplained bruising can also indicate internal bleeding or certain types of cancer. Long-term glucocorticoid therapy can cause easy bruising. Bruising present around the navel (belly button) with severe abdominal pain suggests acute pancreatitis. Connective tissue disorders such as Ehlers-Danlos syndrome may cause relatively easy or spontaneous bruising depending on the severity. Spontaneous bruising or bruising with minimal trauma in the absence of other explanations and together with other minor or major criteria suggestive of Vascular Ehlers-Danlos Syndrome (vEDS) suggests genetic testing for the condition.During an autopsy, bruises accompanying abrasions indicate the abrasions occurred while the individual was alive, as opposed to damage incurred post mortem.
Size and shape
Bruise shapes may correspond directly to the instrument of injury or be modified by additional factors. Bruises often become more prominent as time lapses, resulting in additional size and swelling, and may grow to a large size over the course of the hours after the injury that caused the bruise was inflicted. Condition and type of tissue: In soft tissues, a larger area is bruised than would be in firmer tissue due to ease of blood to invade tissue. Age: elderly skin and other tissues are often thinner and less elastic and thus more prone to bruising. Gender: More bruising occurs in females due to increased subcutaneous fat. Skin tone: Discoloration caused by bruises is more prominent in lighter complexions. Diseases: Coagulation, platelet and blood vessel diseases or deficiencies can increase bruising due to more bleeding. Location: More extensive vascularity causes more bleeding. Areas such as the arms, knees, shins and the facial area are especially common bruise sites. Forces: Greater striking forces cause greater bruising. Genes: Despite having completely normal coagulation factors, natural redheads have been shown to bruise more, although this may just be due to greater visibility on commonly associated lighter complexion. Severity
Bruises can be scored on a scale from 0–5 to categorize the severity and danger of the injury. The harm score is determined by the extent and severity of the injuries to the organs and tissues causing the bruising, in turn depending on multiple factors.