It is a common rash disease in infancy and childhood caused by infection with human herpes virus types 6 (HHV-6) and 7 (HHV-7), mostly seen in infants and children aged 6 months to 1 year. The disease is characterized by sudden onset of fever and rash. Human herpes virus types 6 and 7 have a common characteristic of being aggressive to lymphocytes and are clinically widespread, and are an important cause of acute rash and febrile convulsions in young children. HHV-6 infection can be transmitted by a variety of routes, with horizontal transmission through saliva being the main route of transmission. The human body develops lifelong immunity to this virus after infection. The mode of transmission of HHV-7 is unknown but is closely related to the site of incubation of the virus, which is mainly in peripheral blood mononuclear cells and saliva, and salivary transmission may be an important route. The possibility of transmission through the birth canal or gastrointestinal tract cannot be completely excluded.