After several anxious days of high fever, a child’s fever finally drops, and then a pink rash spreads across the body. Parents often panic at that moment, yet this sequence is the classic pattern of roseola, also called roseola infantum.

Why It Happens

Roseola is usually caused by human herpesvirus 6 (HHV-6), sometimes type 7. Most children are infected once in early childhood, and the virus can spread through respiratory secretions and saliva. AAP HealthyChildren describes the rash appearing after the fever is gone as the key clue for the diagnosis. The rash is thought to reflect the body’s immune response, which is why the skin looks normal while the fever is present.

How It Differs by Age and Stage

Roseola is most common between about 6 months and 2-3 years of age, with many cases in the 6-15 month range. The course usually has two phases.

  • Fever phase: a fever of about 102-105 degrees Fahrenheit (roughly 39-40.5 degrees Celsius) lasts about 3-5 days and can run up to 7. Many children still play reasonably well despite the number on the thermometer.
  • Rash phase: within about 12-24 hours after the fever ends, a pink rash appears on the trunk and may spread to the neck, face and limbs. It is usually not itchy and fades in one to three days. The AAFP photo quiz notes the rash resolves on its own, within roughly 10-14 days of the first fever. Not every child follows this order, and in some the rash is faint.

What to Do at Home

There is no specific treatment, and most children recover with supportive care. During the fever, offer small, frequent sips of fluid and dress your child lightly. Ask the pediatrician to confirm a fever-reducer dose that matches your child’s weight and age. Watch whether your child looks comfortable and whether wet diapers or urination stay close to usual. The rash itself rarely needs cream; keeping nails short can help if the child scratches. AAP says a child can return to child care or preschool once the fever has been gone for 24 hours, even if the rash is still showing, but individual programs may have their own rules.

Common Misunderstandings

Many parents assume the rash is a drug reaction or measles because it appears right after medicine was given. In roseola, the rash comes after the fever ends and the child often looks better. Another misunderstanding is that the rash marks the most contagious time; spread is thought to occur mostly during the fever phase. A third is ruling out roseola because the fever lasted several days with no rash yet. The rash can only be seen once the fever resolves, so roseola is hard to tell from other illnesses while the fever lasts, and a long fever deserves a medical check.

When to Seek Care

A febrile seizure can occur when the fever climbs quickly. A scientific review reports HHV-6 as a studied cause in about 20-25% of febrile seizure cases. Most seizures are brief, but go to the emergency room right away if a seizure lasts more than 5 minutes, your child does not wake up afterward, or breathing looks difficult. Also see a pediatrician for any fever in a baby under 3 months, a fever lasting more than 5 days, a child who is limp or hard to wake, signs of dehydration such as very few wet diapers and a dry mouth, or no rash 24-48 hours after the fever ends while your child is still unwell. This information is based on U.S. and international sources; if you live elsewhere, check with a local pediatrician. This information isn’t a diagnostic tool and doesn’t replace advice from a medical professional.