The causes of bruises on the legs of children mainly include the following: 1, caused by trauma to the legs of children, if children’s legs are traumatized, this will often cause poor circulation of blood in the legs, and even cause bleeding, etc. This situation has a typical history of trauma can be found, you need to give children timely application of blood circulation drugs to improve, such as the application of safflower oil to external application. 2, caused by children suffering from allergic purpura For children with bruises on the legs, it is important to find the specific cause and give targeted treatment, not just a generalization.