Transient Neonatal Pustular Melanosis



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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Nov 2, 2016 | Posted by in PEDIATRICS | Comments Off on Transient Neonatal Pustular Melanosis
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