My 3-year-old child always complained of stomachache, which was diagnosed as lymph node inflammation

Abdominal pain is one of the most common conditions in infants, most likely caused by mesenteric lymphadenitis. This disease is very common and is not fully related to the development of mesentery in children. In the case of cold, strenuous exercise, infection, etc., it may induce mesenteric lymphadenitis.