What is the differential diagnosis for low grade fever in children since one month (99.3-99.8) with no other symptoms?

Normal child: A temperature below 100.5 is not considered a fever. Any differential diagnosis would be more related to other symptoms than the temperature of 99.8 degrees. Infants can get a temperature that high from over wrapping.

FUO: Fever of unknown origin among children : mostly caused by infection, viral respiratory, gi, bacterial infections like otitis media, pneumonia, UTI , strep tonsillitis or th serious meningitis. Bacteremia, leukemia are other diff, dx.

Don't tx numbers: A temp of 99.3-99.8 f really is not considered a fever - conventionally, 100.4 or 101.4 f is used , depending on the situation.. Your question is important but difficult to answer without any other details (signs and symptoms, medications given, other illnesses the patient has). Otherwise, we can't possibly answer the question meaningfully for you. Try again with some details...

Not a fever: This temperature value range is not a fever. There have been normal body temperatures measured as high as 100.6! generally speaking, a fever is considered to be 100.5 or higher at every age range.