Swollen gums in one year old babies are usually a sign of inflammation, or a sign of injury. 1. Inflammation: for example, gingivitis is an early, reversible inflammatory lesions of the gum tissue, the sick child manifested as swollen and painful gums, the child crying, loss of appetite, gingivitis is a periodontal disease. 2. Injury: one year old baby swollen gums can also be caused by trauma, such as bruises, crush injuries, etc., because the affected area is traumatized, poor local blood circulation can cause localized swelling of the gums purple. One year old baby swollen gums, there may be other causes, it is recommended to go to the hospital in time, improve the examination to clarify the cause, under the guidance of the doctor to give targeted treatment or treatment.