Infantile roseola, also known as exanthema subitum, is a common acute febrile rash illness in infants and young children. It is characterized by high fever in children under three years old lasting for 3-5 days, followed by a sudden drop in body temperature. Simultaneously, rose-pink maculopapular rashes appear. One distinguishing feature of the fever associated with this illness is that after three to five days of high fever, body temperature generally spikes, then suddenly drops. Typically, within 24 hours, the temperature returns to normal. After the fever subsides or as the body temperature drops, rashes begin to appear on the skin.