Hi thanks for posting here.A bruise
is a black-and-blue mark caused by bleeding into the skin from damaged blood vessels. Many children older than one year of age develop bruises associated with accidental injury
and physical activity.Most bruises are not a cause for concern Bruises may be abnormal if they occur spontaneously without explanation, if they are in other places than the lower legs (“unexplained” bruises on the shins are usually normal because children often bump this area and then forget that they bumped it), if they are larger than a quarter in size, and if they are lumpy rather than flat.
Bruises may also be abnormal if they are larger than expected for the degree of injury. Abnormal bruising occurs if there is:
A low level of platelets, A low level of clotting factor,Very weak skin ,inherited bleeding disorders,so it will be better you consult a paediatrician and go for detailed evaluation of your child.Take care.