Lymph nodes on the neck of a 6-year-old child may be caused by inflammatory stimuli, but also may be related to blood system diseases, such as lymphoma. 1. Inflammatory stimuli: If a child is infected by bacteria, viruses, mycoplasma, etc., fever, runny nose, cough and other symptoms may occur, and these inflammatory stimuli may lead to the appearance of lymph nodes on the child’s neck, and after the inflammation disappears, the lymph nodes will disappear as well. 2. Blood diseases: In addition to inflammatory stimuli, blood diseases can also lead to the appearance of lymph nodes in children, such as lymphoma, etc. Lymph nodes caused by this condition are usually accompanied by other manifestations, such as pain on pressure, increasing area, etc. Lymph nodes on the neck of a 6-year-old child may have other causes, it is recommended to go to the hospital in time for relevant examinations, to clarify the cause of the disease and then actively treat the symptoms.