Erythema toxicum neonatorum. This very common and completely benign condition usually arises in the first 2 days of life. It is seen in about half of healthy newborns and occurs less frequently in preterm infants. The lesions are erythematous macules, within which papules and pustules may develop. The trunk is the most common site, but all other body surfaces, except for the palms and soles, may be involved. Occasionally' these lesions may occur in plaques. The eruption shown in Fig. 1-1 began 2 hours after delivery and involved the face and trunk.