Generally it is not normal for a toddler to have a low-grade fever all the way through the rash, suggesting that there may be other pathogens such as viruses involved. Acute rash is a kind of infectious disease caused by human herpes virus, usually high fever onset, but the fever is generally better, about 3 to 5 days the body temperature gradually normalized, herpes in a day out, after the condition slowly improve, so the general symptomatic supportive treatment is given priority to. Because of the characteristics of infantile emergency rash is heat and rash, general fever after the rash is not part of the normal course of infantile emergency rash, suggesting that there may be other pathogens such as viruses and other infections. If you find that the child has been low fever after the rash, you should consult a doctor in time, under the guidance of the doctor for standardized diagnosis and treatment, so as not to delay the condition.