There are many reasons why two-year-old babies have recurrent fever, as follows: 1. The most common is fever caused by infection, two-year-old baby infections are common in three major systems of infection, such as respiratory, digestive and urinary tract, each system infection has related symptoms, recurrent fever caused by respiratory infections, there will be nasal congestion, runny nose, sore throat or coughing and coughing symptoms; recurrent fever caused by digestive system diseases The baby may have acute gastroenteritis, appendicitis or mesenteric lymphadenitis, often accompanied by abdominal pain, diarrhea, nausea, vomiting and other symptoms; urinary tract infections may appear frequent and painful urination, due to urinary tract infections stimulate the vulva, the baby often scratching the vulva area and other situations; 2. The cause of the fever can be clarified only by examining the blood routine or rheumatologic immune factor and other related tests.