My son is 5 years old and weighs 50 pounds. I picked him up from school running a 101.6 fever and it escalated to running up to 104.8 at one point but fluctuating with the medicine, Motrin. He has a nasty cough and has been to the doctor twice had flu, strep and mono test 2 times each and all negative. He is still running a fever going on day five. The doctor said to continue the Motrin if needed and if still fever over weekend be back at the office on Monday. How long should a child run this type of fever before something else is done. ie...blood work, chest xray, trip to er?? Im really starting to get concerned. Last night his fever was 104.5 at 3 am. Ive done the luke warm baths and they worked some what.