Transient Neonatal Pustular Melanosis


Background

Neonatal skin lesions are common. Differentiation of the nonsignificant from more serious clinical entities is important. [1234Transient neonatal pustular melanosis, a benign idiopathic skin condition mainly seen in newborns with skin of color, has distinctive features characterized by vesicles, superficial pustules, and pigmented macules. The lesions of transient neonatal pustular melanosis are present at birth. They occur on the chin, neck, forehead, chest, buttocks, back, and, less often, on the palms and soles. [56The vesicles and pustules rupture easily (see the image below) and resolve within 48 hours. The brown macules may persist for several months. [57]

Ruptured pustules and vesicles with remaining charRuptured pustules and vesicles with remaining characteristic collarette of scale and brown hyperpigmented macules. Courtesy of Anthony J. Mancini, 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.

Etiology

The etiology of transient neonatal pustular melanosis is unknown. No familial predisposition has been identified for transient neonatal pustular melanosis.

Increased frequency of placental squamous metaplasia has been reported in the mothers of some of these infants, although this relationship has not been demonstrated in any large trial. [8]

Epidemiology

US frequency

Previously published incidence rates for transient neonatal pustular melanosis are 0.6% in white infants and 4.4% in African American infants. The overall rate has been reported as 2.2%. [9Transient neonatal pustular melanosis is more common in term-gestation infants. [10Transient neonatal pustular melanosis has also been seen in non–African American infants with skin of color, although the literature is sparse.

Race

Transient neonatal pustular melanosis may occur in as many as 5% of African American newborns and less than 0.6% of white infants.

Sex

Transient neonatal pustular melanosis occurs equally in both sexes. [5]

Age

Transient neonatal pustular melanosis is present at birth

Prognosis

Transient neonatal pustular melanosis is a benign, asymptomatic, and self-limited skin eruption with no associated mortality or morbidity. The prognosis for transient neonatal pustular melanosis is good. The vesicles and pustules usually resolve within 48 hours, [11while the brown macules usually fade over 3-4 weeks but may persist for several months. [12]

Patient Education

Reassure the parents that transient neonatal pustular melanosis is a benign, self-limiting condition.

CLINICAL PRESENTATION


History

Often, only pigmented macules are present at birth, in which case the pustular phase may have occurred in utero. Skin findings can be correlated with gestational age at birth. Post-term infants are more likely to have the late finding of pigmented macules. No systemic symptoms are associated with the skin lesions of transient neonatal pustular melanosis. [613]

Physical Examination

Transient neonatal pustular melanosis is characterized by vesicles, superficial pustules, and pigmented macules.

Because of the fragile nature of the superficial pustules, most are broken during the initial drying or cleansing of the newborn. Intact lesions may remain in more protected areas such as beneath the chin, in the axillae, or in the groin. The vesicles and pustules may desquamate during the neonate's first bath, leaving characteristic white collarettes of scale and brown macules. The vesicopustules resolve within 24-48 hours. [9The hyperpigmented macules usually fade within 3-4 weeks, although full resolution may take several months. [12Note the image below.

Ruptured pustules and vesicles with remaining charRuptured pustules and vesicles with remaining characteristic collarette of scale and brown hyperpigmented macules. Courtesy of Anthony J. Mancini, MD.

Depending on the time of the examination in the neonatal period, the vesicles, pustules, and/or pigmented macules may be found predominantly on the chin, neck, or forehead; behind the ears; or on the trunk, palms, and soles. [10]

The lesions are 2-10 mm in diameter. Vesicles and pustules are usually 2-4 mm and are often filled with milky fluid. These lesions lack surrounding erythema. [712]

No systemic signs or symptoms are associated with the skin eruptions.

Papules are not seen in transient neonatal pustular melanosis, but they may be seen in neonates with erythema toxicum neonatorium, acne neonatorum, or miliaria. The vesiculopustular lesions may be similar to lesions seen in acropustulosis. Acropustulosis is also more common in African American infants, but it has a male predominance and pruritic lesions cluster on the palms and soles. [11]

DIFFERENTIAL DIAGNOSIS


Diagnostic Considerations

Also consider the following:

  • Acne neonatorum
  • Congenital candidiasis
  • Impetigo neonatorum
  • Erythema toxicum
  • Staphylococcal infection
  • Ofuji syndrome
  • Neonatal varicella
  • Congenital dermal melanocytosis or Mongolian spots: These are bluish-black macular patches on the back and lumbosacral area; they are more common in dark-skinned babies than in light-skinned babies.

Failure to recognize and distinguish this condition from other neonatal pustular and vesicular dermatoses with more serious systemic implications can be problematic. Infectious causes of vesicles or pustules in the newborn can be bacterial (including spirochetal), fungal, or viral. Congenital herpes simplex infection is an important differential, although in this condition the vesicles and pustules occur in "crops" on erythematous bases. [12Because pustules can be a manifestation of sepsis, it is important to consider all infectious etiologies.

Differential Diagnoses


TREATMENT AND MANAGEMENT

Medical Care

No specific therapy is indicated for transient neonatal pustular melanosis. [51011]

Prevention

Contagious isolation is unnecessary for transient neonatal pustular melanosis.

MEDICATION

Medication Summary

No medication is necessary for transient neonatal pustular melanosis.

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