Pustules, Vesicles, Bullae, and Erosions












CHAPTER 1
PUSTULES, VESICLES, BULLAE, AND EROSIONS

Erythema Toxicum Neonatorum (ETN)







































Synonyms Toxic erythema of the newborn, erythema neonatorum.
Inheritance None.
Prenatal Diagnosis None.
Incidence 50% of full-term infants; M = F.
Age at Presentation 24 to 48 hours of life, may wax and wane during the first 2 weeks. Rarely presents later than 2 weeks of age.
Pathogenesis Exact etiology is unknown. The presence of eosinophils suggests an allergic or hypersensitivity reaction, though no definitive trigger has been identified.
Key Features

Skin


1- to 2-mm papules, pustules, and vesicles ± underlying erythematous macules/patches; sparse, widely dispersed or localized in clusters; face (most common), trunk, and proximal extremities sparing palms and soles. “Flea-bitten appearance,” lesions evolve quickly and may change from the morning to afternoon.

Differential Diagnosis Miliaria rubra (MR), transient neonatal pustular melanosis, acne neonatorum, acropustulosis of infancy (API), eosinophilic pustular folliculitis, impetigo neonatorum, candidiasis, herpes simplex.
Laboratory Data Rarely necessary. Wright’s and/or Giemsa staining of lesional contents will show eosinophils (to distinguish from transient neonatal pustular melanosis).
Management Reassurance.
Prognosis Benign, transient, migratory, self-limited course (up to 1 week).
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1.1. Erythema toxicum neonatorum.


image PEARL/WHAT PARENTS ASK


Did it have something to do with the type of delivery or the pregnancy? No. Will it scar? No. Is it an allergic reaction? No. Is it contagious? No. What should I put on it? Nothing.











Skin | Associated Findings
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Transient Neonatal Pustular Melanosis (TNPM)







































Synonyms Sterile neonatal pustulosis, transient neonatal pustulosis.
Inheritance None.
Prenatal Diagnosis None.
Incidence 5% of full-term skin of color newborns and less than 1% of Caucasian infants.
Age at Presentation Birth.
Pathogenesis Unknown.
Key Features

Skin


Asymptomatic 2- to 3-mm vesicles and superficial pustules lesions that rupture, leaving collarettes of scale sometimes with pigmented macules. Papules and papulopustules last 2 to 5 days. If present, hyperpigmentation resolves over several weeks up to 3 months. Solitary or grouped on the head, neck, and low back, rarely on the scalp, palms, and soles. Scalp lesions can be large and concerning in appearance.

Differential Diagnosis Miliaria rubra, erythema toxicum neonatorum, acne neonatorum, acropustulosis of infancy, eosinophilic pustular folliculitis, impetigo neonatorum, candidiasis, herpes simplex, scabies, congenital self-healing histiocytosis (Hashimoto-Pritzker syndrome).
Laboratory Data Rarely necessary, clinical diagnosis. Wright stain can identify neutrophils; eosinophils vary in number (as compared to erythema toxicum neonatorum).
Management Reassurance.
Prognosis Self-limited with complete recovery. Possible risk of residual hyperpigmentation.
image

1.2. Transient neonatal pustular melanosis.


image PEARL/WHAT PARENTS ASK


Did it have something to do with the type of delivery or the pregnancy? No. Will it scar? No, though in some cases the hyperpigmentation could remain present to a certain degree. Is it an infection or an allergic reaction? The cause is not known. What should I put on it? Nothing. Since it is a self-limited condition, and really does not respond to therapy, no treatment is necessary. If there is any residual hyperpigmentation, parents can consider treating with over-the-counter fading products (ie, 2% hydroquinone), but this is rarely necessary.











Skin | Associated Findings
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Miliaria







































Synonyms Miliaria crystallina (MC)-sudamina; miliaria rubra (MR), or prickly heat, or heat rash; miliaria profunda (MP) or tropical anhidrosis.
Inheritance None.
Prenatal Diagnosis None.
Incidence MC and MR are present in approximately 5% of newborns.
Age at Presentation

  • MC: Birth to 1 week.
  • MR: Mean age ~2 weeks; may occur in older infants.
  • MP: Rare in children, a possible complication of recurrent MR.
Pathogenesis

Immature, underdeveloped eccrine sweat duct with secondary sweat accumulation, not associated with the hair follicle.



  • MC: Occlusion at the most superficial part of the duct; accumulation of sweat within the stratum corneum.
  • MR: Occlusion of the intraepidermal portion of the duct with inflammatory response; can be complicated by Staphylococcus aureus (miliaria pustulosa [M. pustulosa]).
  • MP: Inflammatory reaction from sweat leakage into dermis; from recurrent MR.
Key Features

Skin



  • MC: Asymptomatic; 1- to 2-mm clear, thin-walled monomorphous vesicles on normal appearing skin; face, neck, and upper chest.
  • MR: Pruritic, prickling sensation; 2- to 4-mm confluent papules/papulovesicles ± pustules, on erythematous base in the intertriginous zones and occluded area, back most common.
  • MP: Asymptomatic deep, flesh-colored papules, trunk, and extremities.
Differential Diagnosis

  • MC: Herpes simplex, varicella zoster, epidermolysis bullosa (EB).
  • MR: Erythema toxicum neonatorum, neonatal acne, contact dermatitis, eosinophilic pustular folliculitis, scabies, bacterial folliculitis.
  • MP: Erythema toxicum neonatorum, acne.
Laboratory Data Rarely necessary though on Gram stain may see some degree of acute inflammation with ± Gram-positive cocci in MR.
Management Prevention is key, avoid over exposure to heat. Reverse environmental conditions from hot and humid to cool and dry.
Prognosis

  • MC: Self-limited.
  • MR: Can be prolonged depending on environmental factors. Staph species may cause secondary infection leading to MP. Repeated bouts of MR may develop into MP; recurrences are self-limited; peaks in second week of life.

image PEARL/WHAT PARENTS ASK


What makes this happen? You need 3 things for this to develop: heat, humidity, and sweat. What can I do to make it better? Use cool compresses in sensitive areas and bathe in tepid water. Cotton, loose fitting clothing and topical treatments offer little relief. Common even in winter when cold because of bundling with occlusive clothing. Why does my baby get it, but my older kids don’t? Infants are more likely to develop this type of rash because of the high number and immaturity of their sweat ducts. Is it contagious? No. Will it come back? Potentially, depending on environmental factors.











Skin | Associated Findings
image
image

1.3. Miliaria crystallina.


Neonatal Acne







































Synonyms Acne neonatorum, baby acne.
Inheritance None.
Prenatal Diagnosis None.
Incidence 20% of normal term infants, M > F.
Age at Presentation Neonatal: 2 to 3 weeks; infantile: 3 to 6 months.
Pathogenesis

Neonatal: Endogenous and maternal androgens stimulating hyper-responsive sebaceous glands, ± Malassezia species.


Infantile: Hyperplasia of sebaceous glands secondary to androgenic stimulation, genetic predisposition.

Key Features

Skin



  • Neonatal: 1- to 3-mm erythematous papules and papulopustules chin, cheeks, forehead.
  • Infantile: 1- to 3-mm open/closed comedones, erythematous papules, pustules, and sometimes nodules on chin, cheeks, forehead.
Differential Diagnosis Erythema toxicum neonatorum, neonatal cephalic pustulosis, MR, eosinophilic pustular folliculitis, impetigo neonatorum, seborrheic dermatitis.
Laboratory Data Rarely necessary; if severe and/or recalcitrant then evaluation for underlying androgen excess.
Management

In prepubertal children with inflammatory acne not responding to topical therapy, oral antibiotics and rarely isotretinoin may need to be considered.


Reassurance, gentle cleansers; if persistent or severe, then 0.025% tretinoin cream qhs, ± benzoyl peroxide wash or 2% topical erythromycin gel.

Prognosis Neonatal acne clears in several months but occasionally develops into infantile acne that may be present until 12 to 15 months.

image PEARL/WHAT PARENTS ASK


Will it scar? Rarely yes, but not usually. I had bad acne as a teen, is that related to my baby’s acne? Yes, in the infantile acne form, there is a potential genetic predisposition if the baby’s parents had adolescent acne. Is it because I haven’t bathed my baby yet? No, it doesn’t have anything to do with cleanliness.











Skin | Associated Findings
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Acropustulosis of Infancy (AI)










































Synonym Infantile acropustulosis.
Inheritance None.
Prenatal Diagnosis None.
Incidence Unknown.
Age at Presentation Birth to 3 years, typically between 2 and 10 months, more common in black male infants, and course may be prolonged.
Pathogenesis Unknown, but may develop after a scabies infection.
Key Features

Skin


Pruritic erythematous 1- to 2-mm papules; evolve into vesicopustular lesions on palms, soles; ± dorsal surface of hands and feet, face, scalp and trunk; ± post-inflammatory hyperpigmentation, ± crust, lichenification; crops can last up to 1 week and recur every 2 to 4 weeks for up to 3 years.


General: Irritability, sleeplessness secondary to pruritus.

Differential Diagnosis Scabies, transient neonatal pustular melanosis, acne neonatorum, eosinophilic pustular folliculitis, impetigo neonatorum, candidiasis, herpes simplex, dyshidrotic eczema.
Laboratory Data Gram stain will show largely neutrophils; occasional eosinophils, though not as prominent as in erythema toxicum neonatorum.
Complication Secondary bacterial infection.
Management

Systemic antihistamines (hydroxyzine 2 mg/kg/day divided every 6-8 hours).


Moderate-to-high potency topical corticosteroids to affected areas bid (eg, triamcinolone or clobetasol).

Prognosis Recurrent; self-limited, complete resolution by age 3.
image

1.4. Acropustulosis of infancy.


image PEARL/WHAT PARENTS ASK


Is this an allergic reaction? No. Why is my baby crying so much; does it hurt? No it doesn’t hurt, but infants are not coordinated enough to scratch effectively so they cry instead. Is this an infection of the skin? No, but it’s important to keep in mind two things: secondary infection can occur; association with scabies infestation. Hyperpigmentation will resolve, though slowly.











Skin | Associated Findings
image

Neonatal Candidiasis
























Synonyms

Localized to skin: Congenital cutaneous candidiasis (CCC).


Systemic: Invasive fungal dermatitis (IFD); systemic candidiasis (SC).

Inheritance None.
Prenatal Diagnosis None.
Incidence

Localized to skin: CCC rare.


Systemic: IFD or SC 2% to 28% (average 9%) of extremely low birth weight infants (ELBW is <1,000 g); third leading cause of late onset sepsis in the neonatal intensive care unit (NICU).

Age at Presentation

Localized to skin: CCC, birth to day 6 of life.


Systemic: IFD, first 2 weeks of life; SC, second to sixth week of life.

Pathogenesis

Localized to skin (acquired in utero)



  • CCC: Candida albicans (C. albicans

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    Aug 17, 2025 | Posted by in PEDIATRICS | Comments Off on Pustules, Vesicles, Bullae, and Erosions

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