Viral fever in 3-month-old babies may be a rash, but the result is not absolute. When 3-month-old babies infected with human herpesvirus type 6, type 7 and triggered by toddler rash, the body will suddenly appear high fever phenomenon, body temperature in a short period of time may rise to 39 ° C, after the fever subsides, the body will grow pink small dense maculopapular rashes, and quickly spread from the neck, chest, abdomen to the limbs and face, this kind of viral fever is indeed out of the rash. However, not all viral fevers are indicative of a rash. For example, when a 3-month-old baby has an upper respiratory tract infection caused by respiratory syncytial virus or parainfluenza virus, he or she may also have a fever due to the severity of the illness, and in the case of rotavirus infections that lead to enterocolitis, the body usually has a fever, but none of these illnesses will cause a rash. Regardless of whether or not it causes a rash, when you find that your baby has a fever, you need to go to a regular hospital for timely treatment.