Synonyms for Roseola Infantilis (same or very similar meaning)
WordNet sense 1 (a viral disease of infants and young children; characterized by abrupt high fever and mild sore throat; a few days later there is a faint pinkish rash that lasts for a few hours to a few days):
pseudorubella, exanthema subitum, roseola infantumFrom the ODE community, based on WordNetadd/edit