Rash after fever in 6-month-old babies may be due to measles, rubella, toddler’s emergency rash and other factors. 1. Measles: Measles is usually caused by the measles virus infecting the mucous membranes of the upper respiratory tract. It will cause the baby to have fever, and after three days of fever, red macules will appear on the face and the whole body, and then spread from top to bottom to the limbs, without itching. 2. Rubella: Because the baby’s body resistance is weak, when infected by the rubella virus, it will also cause fever and rash symptoms, accompanied by cough, runny nose, swollen lymph nodes, sore throat and other symptoms. The rash usually appears as a reddish macular rash with a pinpoint appearance. 3. toddler’s emergency rash: when the baby suffers from toddler’s emergency rash, it will also cause fever after the symptoms of the rash, the fever is usually higher than 39 ℃, and the rash will appear pink small dense maculopapular rash, accompanied by bumps. The fever begins to subside after the rash appears. 6-month-old baby rash after fever, there may also 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.