erythema infectiosum, 1. an acute benign infectious disease, mainly of childhood, characterized by fever and an erythematous rash that begins on the cheeks and later appears on the arms, thighs, buttocks, and trunk. As the rash progresses, earlier lesions fade. Sunlight aggravates the eruption, which usually lasts about 10 days but may recur in 1 to 3 weeks or longer after exposure to sunlight or heat. For a period the rash may reappear whenever the skin is irritated. It is caused by parvovirus B19. Morbidity is more significant in adults, immunocompromised patients, pregnant women, and those with uremia. 2. a virus that lives only in humans. No treatment is necessary, and prognosis is excellent. Isolation of patients is not required. Also called fifth disease.
