Fig. 24.1
Pustules and denuded lesions with residual discoloration in a Mexican infant (photo courtesy of Carola Duran McKinster)
Lastly, within hours of exposure to the atmospheric environment, the central hyperpigmented brown macule becomes apparent [4]. Macules are round, have smooth and distinct borders, and may frequently be confused for freckles. They may be profuse or sparse and are commonly found under the chin and on the neck, upper chest, back, and buttocks. Sometimes, the palms, soles, and scalp are affected.
No systemic signs or symptoms are associated with the skin lesions of TNPM [6, 15]. The vesicopustules typically disappear within 24–48 h of birth [3, 4, 7, 8]. The hyperpigmented melanotic macules usually fade spontaneously over the course of 3–4 weeks, although full resolution may occasionally take several months [3, 5]. The etiology of TNPM remains unknown. No familial predisposition has been identified for TNPM. Increased frequency of placental squamous metaplasia has been reported in the mothers of some infants, although this relationship has not been demonstrated in any large clinical trial [20].
Summary Points
TNPM is characterized by small clustered vesicles and superficial pustules that rupture easily, leaving collarettes of thin white scale and brown hyperpigmented macules.
The skin lesions of TNPM are not associated with any systemic signs or symptoms.
The vesicopustules generally disappear within 24–48 h of birth; the brown macules fade spontaneously within 3–4 weeks, although full resolution may take several months.
Diagnostic Evaluation
The diagnosis of TNPM is usually made by clinical examination [3, 5]. If the clinical presentation is typical of TNPM (i.e., vesiculopustular lesions with hyperpigmented macules present at birth), a full diagnostic workup is generally not indicated. Conversely, if appearance is not typical, cytologic and histologic investigations are warranted to rule out other vesiculopustular dermatoses that can be the presenting features of serious infectious, inflammatory, or genetic neonatal disorders [3]. Thus, it is important to rapidly and confidently differentiate between benign and serious conditions (Table 24.1), so as to take immediate and effective action should the need arise. The goal of this diagnostic approach is to spare a healthy neonate with TNPM either potentially harmful antibiotic or antiviral therapy, an invasive evaluation for sepsis, or prolonged hospitalization, all of which have their own inherent morbidity [5].
Table 24.1
Differential diagnosis of neonatal vesiculopustular dermatoses by etiology
Dermatosis | Clinical presentation | Diagnostic test | Cytologic/histologic results |
|---|---|---|---|
Noninfectious disease | |||
EPF | Crops of papules, vesicles, and pustules that crust, predominantly on scalp with some lesions on the trunk and extremities | Tzanck smear | Eosinophils and neutrophils |
Gram stain | No bacteria | ||
ETN | Red macules and papules; white to pink pustules; vesicles on the face, trunk, and extremities | Tzanck smear | Abundant eosinophils, rare neutrophils |
Gram stain | No bacteria; abundant eosinophils | ||
Incontinentia pigmenti | Linear irregular vesicular and bullous lesions (rarely pustular) over the trunk and extremities | Tzanck smear | Abundant eosinophils |
Biopsy | Intraepidermal eosinophilic spongiotic pustules; dermal infiltrate with many eosinophils mixed with lymphocytes in an extrafollicular location | ||
Infantile acropustulosis | Red papules evolving into pustular and vesicular lesions within 1 day | Tzanck smear | Eosinophils predominate early on; neutrophils predominate later on |
Gram stain | No bacteria | ||
Biopsy (rare) | Intraepidermal vesicles early on; subcorneal pustules (mostly PMN leucocytes); mild perivascular infiltrate | ||
Neonatal acne | Closed comedones mainly; open comedones, papules, and pustules in the face | Gram stain | Bacteria and yeast cells |
Culture | Bacteria (Staphylococcus epidermidis, Propionibacterium acnes) and yeasts (Pityrosporum ovale) | ||
Pustular miliaria | Generalized grouped erythematous papules and pustules with an increase in the intertriginous areas | Tzanck smear | Lymphocytes predominate |
Gram stain | No bacteria | ||
TNPM | Vesicles and pustules desquamate leaving brown macules on chin, neck, palms, and soles
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