Roseola is a viral infection that mostly affects babies and young children, typically in the first two years of life. It is caused by a type of herpes virus, usually human herpes virus 6 or sometimes human herpes virus 7, and is spread by contact with an infected persons saliva, such as when sharing a cup, or through the air, such as when a person with roseola coughs or sneezes. It takes about 5 to 15 days for symptoms to develop after exposure to an infected person.

The main symptom of roseola is a sudden, high fever that lasts about three to four days, which can cause febrile seizures in some children. After the fever breaks, some children develop a rash that lasts two to four days. The rash is either flat or raised lesions on the abdomen and then spreads to the face, arms, and legs. Most children can recover at home in a week or less.

Roseola is contagious and spreads through the saliva and respiratory droplets (from a cough or sneeze) of someone who has a fever or doesn’t yet have symptoms. It is most contagious during the fever phase, and a child can return to childcare or preschool after the fever goes down and the rash breaks out. There is no vaccine to prevent roseola, but good hand-washing habits can help prevent viral infections.