Whether or not a rash after a fever is almost over depends largely on the type of rash. If it’s infantile rash, it means it’s almost over, and if it’s measles, it means the illness has only just begun. Rubella and scarlet fever usually take 3 to 5 days to clear up. 1. Childhood emergency rash: the cause of the rash is different and the duration of the disease is also different. If the rash appears with fever and it is childhood emergency rash, it usually takes about three days for the rash to subside. This means that the disease will soon be cured. 2. Measles: If the rash after the fever is measles, such as urticaria, it usually takes about a week for the rash to subside, indicating that the disease has only begun, and need to be actively treated, because urticaria has a relatively long course. 3. Rubella: the rash appears after one day of fever, accompanied by the phenomenon of elevated body temperature, usually takes 3~5 days to gradually subside. 4. Scarlet fever: the rash appears within a few hours or a day after the onset of fever, the body will have a red rash, which may also be an allergic reaction, and will gradually subside in 3 days. Rash after fever should go to the hospital in time to clarify the diagnosis, for the cause of the active treatment.