Pediatric Erythema Toxicum

Updated: May 07, 2019
  • Author: Amanda Shepard-Hayes, MD; Chief Editor: Dirk M Elston, MD  more...
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Practice Essentials

Erythema toxicum neonatorum (ETN) is a common, benign, and self-limiting condition characterized by small papules or pustules surrounded by an erythematous wheal or macule. It typically appears within the first 2-4 days of life in term neonates and resolves within the first 2 weeks of life.



Erythema toxicum neonatorum (ETN) is a benign, self-limited, asymptomatic skin condition that only occurs during the neonatal period. [1, 2, 3, 4] The eruption is characterized by small, yellowish papules and pustules. The lesions are usually surrounded by an irregular erythematous macule or wheal. Individual lesions are transitory, often disappearing within hours and then appearing elsewhere on the body. They may occur anywhere on the body aside from the palms and soles. See the image below.

A 5-day-old newborn with erythematous papules with A 5-day-old newborn with erythematous papules with surrounding indistinct blotchy erythema visible on the abdomen. Image courtesy of Jining I. Wang, MD.

See 13 Common-to-Rare Infant Skin Conditions, a Critical Images slideshow, to help identify rashes, birthmarks, and other skin conditions encountered in infants.



The underlying mechanism of erythema toxicum neonatorum (ETN) is unknown, although various hypotheses have been described. [5]



The underlying pathophysiology is uncertain. The characteristic presence of eosinophils within the lesions has led some investigators to attribute this condition to an allergy. Work by Eitzman and Smith suggested that eosinophilia is part of the normal spectrum of the nonspecific inflammatory response in the neonate. [6] This hypothesis is supported by cases in which premature neonates have infrequent eruptions that resolve within a few weeks after birth when the neonatal immune response matures.

The etiology of erythema toxicum neonatorum (ETN) remains uncertain; however, more recent hypotheses explaining the appearance of this eruption include the following:

  • Relative, increased, ground-substance viscosity in neonatal skin, with associated trauma leading to eosinophilic inflammation
  • Self-limited, acute, cutaneous, graft versus host reaction caused by maternal lymphocytes in the relatively immunosuppressed fetal circulation, [7] although no maternal cells have been found within the lesions [8]
  • An innate immunologic response to commensal microbes within hair follicle epithelium [9]
  • An inflammatory response mediated by various inflammatory mediators, including aquaporins, psoriasin, and nitric oxide synthases



United States

Erythema toxicum neonatorum (ETN) affects 30-70% of newborns. [10] Carr and associates studied 270 newborns and found an incidence of 48%. [11] Keitel and Yadav studied 207 consecutive newborns and found an incidence of 62%. [12]


Incidence is 25.3% in Spain, 33.7% in Taiwan, 20.6% in India, and 21.3% in Brazil. [4, 13, 14] In one geographically limited study in Brazil, the development of erythema toxicum neonatorum was correlated with birth during the spring through autumn months. [14]


No significant differences based on race are apparent. A study by Saracli and associates documented a low incidence among black neonates; however, this may be caused by the relative difficulty of diagnosing neonates with darker skin. [15] Other sets of observations have noted no racial difference in incidence.


In previous studies, no significant difference in incidence is noted between the sexes. However, a study from China indicated a statistically significant predilection in boys. [16]


This condition is limited to the neonatal period. In a study of 270 cases, the typical newborn with erythema toxicum neonatorum was of average birth weight and born at term. [11] Of the newborns affected, 88% weighed 2500 g or more. In addition, 98% were born at least 35 weeks' gestation, with 85% born at least 39 weeks' gestation.



The prognosis is excellent. The lesions typically resolve within 2 weeks, and no cutaneous or systemic sequelae are generally observed. This is a benign, asymptomatic, self-limited skin condition with no known sequelae.


Patient Education

Parents with older children often are not concerned by the appearance of erythema toxicum neonatorum, but first-time parents should be informed in the perinatal period that an evanescent rash is likely to appear within the first 2 weeks of life. They should be reassured regarding the benign, self-limited, asymptomatic nature of this and other eruptions. [17]

Review the clinical features with parents before they go home. If any concerns arise about an atypical rash, they should be comfortable contacting their primary care physician to discuss the issues. Before discharge, appropriately screen neonates who have risk factors for sepsis or neonatal herpes simplex virus infection.