Baby fever after the body rash is mostly due to toddler emergency rash, allergic rashes and other causes. 1. toddler rash, the child has a high fever lasting more than three days, after the fever appears rash, may be toddler rash, and in the four months to one year old baby more need to be vigilant about this kind of disease. 2. the possibility of allergic rashes, the child fever more need medication to reduce fever, if itself allergic to drugs, it may be allergic rashes, for a large area of the hives like hives can prove this disease. The baby fever after the body rash, there may be other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.