Roseola infantum, also known as exanthema subitum, is caused by human herpesvirus type 6 or type 7. It is an acute febrile infectious disease that evolves over time. The fever may last three to five days. It's important to keep warm, especially in winter, as failure to do so can worsen the child's condition. However, going out is generally fine as long as proper precautions are taken to avoid aggravating the child's illness. Still, it is crucial to intensify care, maintain a light diet, and provide a quiet and comfortable environment for the child, all of which are beneficial for recovery.