Erythema Toxicum Neonatorum Clinical Presentation

Updated: Jul 10, 2017
  • Author: Neil F Gibbs, MD; Chief Editor: William D James, MD  more...
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Presentation

History

When evaluating for erythema toxicum neonatorum (ETN), focus the history on age at onset of the eruption, absence of systemic signs (eg, fever, irritability, lethargy, mucocutaneous involvement), or maternal history of herpes simplex/varicella viral infection, bacterial pyoderma, or candidiasis. [15]

Infants with erythema toxicum neonatorum are otherwise healthy and lack systemic symptoms. The eruption is self-limited with most cases resolving within 5-14 days without residual sequelae. Recurrences are uncommon but have been reported up to the sixth week of life. They tend to be mild in severity.

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Physical Examination

Focus the physical examination on location, size, and distribution of macules, wheals, papules, and pustules on the skin. Note the absence of mucosal, palmar, or plantar involvement (ie, non – hair-bearing skin). Signs of systemic toxicity, including hypothermia or hyperthermia, lethargy, and irritability, are not associated with erythema toxicum neonatorum.

Erythema toxicum neonatorum most commonly presents with a blotchy, evanescent, macular erythema, often on the face or trunk.

The macules are irregular, blanchable, and vary in size.

In more severe cases, pale yellow or white wheals or papules on an erythematous base may follow. In approximately 10% of patients, 2-4 mm pustules develop.

Numbers and distribution of lesions vary from a few and widely scattered to numerous and extensive.

Sites of predilection include the most commonly include the trunk, buttocks, and proximal limbs, but lesions may occur anywhere, including the genitalia. [16] Involvement of the mucous membranes and palms and soles rarely occurs.

See the images 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.
Yellow pustules, some with evidence of rupture, in Yellow pustules, some with evidence of rupture, in a full-term infant at 6 hours of life.
Erythematous blotchy patches localized to the trun Erythematous blotchy patches localized to the trunk in a neonate.
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Causes

The cause of erythema toxicum neonatorum is unknown. Multiple theories have been proposed to explain this common disorder.

Neonates have an increased number of hair follicles compared with adults, and the occurrence of erythema toxicum neonatorum in non–hair-bearing areas such as palms and soles is rare. Inflammatory cells tend to concentrate around hair follicles, and coccilike microbes have been demonstrated in the follicular epithelium and inside the inflammatory cells. This suggests that erythema toxicum neonatorum may be a response to microbes that have penetrated the hair follicle. This process may possibly be integral in developing the new immune system. [17]

The high frequency of eosinophilia suggests an allergic basis, leading some authors to suggest that erythema toxicum neonatorum may be an immediate hypersensitivity reaction to a substance passed from the mother transplacentally; however, convincing support is lacking for this theory. [18]

No responsible exotoxin, allergen, component of sebum, or infectious agent has been linked credibly to erythema toxicum neonatorum.

Medications administered to newborns and the mode of feeding have no effect on incidence.

Other proposed theories include a transient adjustment reaction of the skin to mechanical or thermal stimulation or an acute graft-versus-host reaction induced by the maternal-fetal transfer of lymphocytes before or during delivery. [19] Analysis of skin samples of 2 male patients with erythema toxicum neonatorum did not support a graft-versus-host reaction because no maternal cells were found in the samples using fluorescence in situ hybridization identification of cells with 2 XX chromosomes. [20]

Risk factors include higher birth weight, greater gestational age, and vaginal delivery. A positive correlation has been recognized between the length of labor and both the incidence of erythema toxicum neonatorum and the duration of the cutaneous manifestations. [9, 21]

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