Erythema infectiosum is a disease that occurs in childhood, most often between the ages of 3 and 15. It is called the “Fifth disease” because it is among the diseases that appear most often in childhood – measles, scarlet fever, rubella and rubella-scarlatina (Scarlatiniform rubella Filatov-Duke variant). It is a mild but contagious disease that is caused by a specific type of virus – Parvavirus B19. Erythema infectiosum resembles rubella, but unlike it, it proceeds with fewer complications and with preservation of a better general condition. Most often, this infection passes mildly, with minor malaise, slightly elevated temperature and muscle pains. In some patients, it appears with a characteristic rash on the skin.