Roseola (also known as sixth disease, exanthem subitum, and roseola infantum) is a mild self-limited illness that mainly affects children and is defined by its classic exanthem. Human herpesvirus (HHV)-6 and HHV-7 have been implicated as causal agents. Maternal antibodies are protective prior to the age of 6 months. Infants with roseola are typically between the age of 6 months and 1 year. The disease course classically begins with a high fever typically greater than 38.9°C (102°F). The infant is otherwise well and the fever usually subsides on the fourth day.

The fever is followed immediately by the onset of asymptomatic, rose-pink, blanchable macules and papules 2-3 mm in diameter that begin on the trunk and may spread to the neck, upper extremities, and lower extremities. The rash typically lasts 1-2 days but can resolve more quickly.