Neonate with Blister
Answer C.
Newborns (less than one week of age) and neonates (less than one month of age) are high-risk patients in the ED because of the myriad of signs and symptoms that overlap with both dangerous and benign conditions. Evaluation and management can be more difficult in the emergency setting, due to parental stress, inherent time constraints in the department, and the tendency for these children to appear relatively well in the early course of disease.
Any child less than one month presenting with any possible source of infection, however minor- or superficial-appearing, necessitates a full septic workup, given this age group’s developing immune system, proclivity for hematogenous spread of infection, and risk of crossing the blood-brain barrier via “leaky” tight junctions. If a potentially infectious etiology is entertained, the emergency physician must assume that the newborn or neonate is at risk for overwhelming infection.
Impetigo and its variant, bullous impetigo, are commonly caused by group A Streptococcus or Staphylococcus aureus. The bullous form is caused by strains of S aureus that produce toxin A, causing loss of cell adhesion (targets desmoglein, as seen in pemphigus). Bullous impetigo (A) is typically a focal infection with groupings of bullae on an erythematous/at times cellulitic background (see image below).
Bullous impetigo
Neonatal Dermatology, Auckland District Health Board
Newborns (less than one week of age) and neonates (less than one month of age) are high-risk patients in the ED because of the myriad of signs and symptoms that overlap with both dangerous and benign conditions. Evaluation and management can be more difficult in the emergency setting, due to parental stress, inherent time constraints in the department, and the tendency for these children to appear relatively well in the early course of disease.
Any child less than one month presenting with any possible source of infection, however minor- or superficial-appearing, necessitates a full septic workup, given this age group’s developing immune system, proclivity for hematogenous spread of infection, and risk of crossing the blood-brain barrier via “leaky” tight junctions. If a potentially infectious etiology is entertained, the emergency physician must assume that the newborn or neonate is at risk for overwhelming infection.
Impetigo and its variant, bullous impetigo, are commonly caused by group A Streptococcus or Staphylococcus aureus. The bullous form is caused by strains of S aureus that produce toxin A, causing loss of cell adhesion (targets desmoglein, as seen in pemphigus). Bullous impetigo (A) is typically a focal infection with groupings of bullae on an erythematous/at times cellulitic background (see image below).
Bullous impetigo
Neonatal Dermatology, Auckland District Health Board
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Herpes simplex virus infection (B) should always a consideration in a newborn with a vesicular lesion, with an estimated 1,500 cases in the U.S. annually (fluctuating with incidence of HSV-2 in the general population). There are three main presentations of neonatal HSV: intrauterine, perinatal, and postnatal. Intrauterine HSV is rare and can result in intrauterine growth retardation, CNS and eye defects, or miscarriage (i.e. one of the “TORCH” viruses). 85-90% of HSV in the neonatal period occur in the perinatal period. Risk factors include vaginal delivery, maternal HSV infection (although not required for transmission to the child), use of a scalp monitor during labor, and prolonged rupture of membranes. Newborns typically present within the first week of life with non-specific signs and symptoms, such as irritability, respiratory distress, and temperature dysregulation; up to 80% will have some evidence of a vesicular rash (see image below). Postnatal infections occur later, typically when an adult with herpes labialis kisses the child and infects him.
Neonatal herpes simplex
AAP Redbook, Herpes Simplex, Figure 21
Neonatal herpes simplex
AAP Redbook, Herpes Simplex, Figure 21
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Fortunately, this child has a single, non-infectious vesicle on his hand that is consistent with a “sucking blister”. These lesions are present at birth: in the womb babies may exhibit excessive sucking activity, especially on the hand and forearm. The bullous lesion may burst spontaneously days later. The location, absence of other lesions, and the benign appearance (D) are helpful in making the diagnosis (C).
Sucking blister
Neonatal Dermatology, Auckland District Health Board
Sucking blister
Neonatal Dermatology, Auckland District Health Board