A bruise on the baby’s back may be a congenital birthmark or hemangioma, or it may be a subcutaneous petechiae. If there is any abnormality, parents should take their children to the hospital for examination and targeted treatment after clarifying the cause. Common causes: 1. Birthmarks: The appearance of bruises on the back is considered a skin birthmark, which is caused by congenital factors and is related to the active melanocytes in the dermis. Parents should pay attention to observe changes in the birthmark and visit the hospital if necessary; 2, hemangioma: hemangioma is also due to congenital factors, so you need to pay attention to observe any changes and promptly treat any abnormalities; 3, subcutaneous petechiae: babies with trauma or abnormal blood clotting function and platelets can lead to subcutaneous cyanotic petechiae, which will not fade after pressure. Parents should pay attention to observe whether there are petechiae in other parts, or whether there is vomiting bleeding or oral bleeding, and if there is any abnormality, they should seek medical examination in time. Treatment methods: 1, baby birthmark can follow the doctor’s advice, using laser, freezing or carbon dioxide treatment, these methods are less invasive, generally will not leave scars; 2, hemangioma as the baby grows up, some will gradually fade, fading is not obvious can follow the doctor’s advice to choose laser or oral insulin treatment; 3, due to trauma caused by bruising, can be used cooked egg hot compress, cold towel or ice pack ice, or under the guidance of the doctor Use Yunnan Baiyao spray, safflower oil, etc. to rub the bruises to help dissipate the stasis and reduce swelling; 4. Babies with abnormal coagulation function and platelets can go to the hospital for routine injection of vitamin K1, and those with serious conditions can be treated with fresh frozen plasma or cold precipitation to supplement coagulation factors. Note: The safety of the baby’s life should be strengthened at ordinary times, and attention should be paid to avoid bumping to prevent bruises behind the baby due to trauma.