An Image for Differential Diagnosis

It is the most common transient rash in healthy neonate, which is a benign, self-limiting, physiological rash affecting about 50% of term newborn. It is rarely seen in preterm infants. They usually begin at 1 to 2 days of age, but may occur at any time until about the fourth day. Blotchy erythematous macules 1 to 3 cm in diameter with a 1 to 4 mm central vesicle or pustule are seen in erythema toxicum neonatorum (ETN). Number of lesions can vary from one or two to several hundred. They are not only more profuse on the trunk, but also commonly appear on face and proximal limbs and spares palms and soles. The infant appears well, unperturbed by the eruption. Spontaneous recovery usually occurs within 3 to 7 days without any residual pigmentation . A smear of the central vesicle or pustule contents reveals numerous eosinophils on Wright stain preparations. No organisms can be seen or cultured. A peripheral blood eosinophilia of up to 20% may be associated with severe cases.  No treatment is indicated and apprehensive parents can be reassured about the benign nature of the eruption.