The evaluation of pediatric patients with rashes is a common occurrence in the Ped ED… and a common area of frustration for many of us (ok, maybe it is just me).  We have previously covered an approach to the evaluation of the Pediatric Rash.  We have also covered a variety of common causes of pediatric rashes (ex, Scabies, Tinea, Diaper Dermatitis and Molluscum) including eczema. While many of these conditions are simple nuisances, some can become more problematic. Let’s make sure we stay vigilant for Eczema Herpeticum.

Eczema Herpeticum: Basics

• Atopic dermatitis is an inflammatory skin disease
• The inflammatory states creates an impaired skin barrier
• The impaired protection increases risk for bacterial and viral infections

• Eczema herpeticum
  • A HSV skin infection that occurs in patients with atopic dermatitis.
  • Occurs in 3-6% of patients with atopic dermatitis.
  • Can be due to HSV1 or HSV2, but also other viruses can cause it (ex, varicella, poxvirus)
  • May occur with either primary or recurrent HSV infection. [Wollenberg, 2003]
  • More likely to occur in those patients with:
    • Extensive eczema skin involvement
    • Early onset of eczema [Wollenberg, 2003]
    • Eczema lesions on head and neck
    • High IgE levels
  • Children who are young (1 year or younger) or have systemic illness (ex, fever) are more likely to require hospitalization. [Luca, 2012]
  • Fortunately, overall mortality is low. [Aronson, 2013; Aronson, 2011]

Eczema Herpeticum: Presentation

• Systemic symptoms
  • Fever
  • Malaise
  • Lymphadenopathy

• Skin eruption
  • Monomorphic eruption of dome-shaped vesicles 
    • Initially starts in region of eczema
    • Can spread to involve normal skin also
  • Lesions may crust and form superficial pits and erosions
  • Head, neck, and trunk frequently affected.
    • Lesions can affect the eye and cause keratoconjunctivitis.
  • Fluid from vesicles can be sent for HSV PCR or viral culture to confirm diagnosis.

• May have bacterial infection superinfection 
  • S. aureus is commonly cultured (~30%). [Aronson, 2011]
  • Septicemia cases can occur, but less commonly (~3%).  [Aronson, 2011]

• Dissemination of HSV
  • Multiple organ involvement
  • DIC
  • Meningitis/encephalitis

Eczema Herpeticum: Treatment

• Acyclovir is the traditional therapy
  • Depending on severity of condition, oral or IV is appropriate
  • Oral acyclovir has low bioavailability, so only use for mild cases.
• Delayed administration of acyclovir in hospitalized patients is associated with increased length of stay. [Aronson, 2011]
  • Each day of delayed initiation of acyclovir increased LOS.
  • Challenging to recognize, but important to consider and initiate therapy early, similar to neonatal HSV.

• Steroids
  • Topical steroids
    • Concern that topical steroids may increase spread of HSV infection.
    • Topical steroids are not definitively associated with worsening disease and prolonged LOS.  [Aronson, 2013; Aronson, 2011]
    • May be prudent to wait until acyclovir has been initiated.  [Aronson, 2011]
  • Systemic steroids do worsen eczema herpeticum and increase LOS.  [Aronson, 2013; Aronson, 2011]

• Antibiotics
  • Empiric antibiotics for all kids have not shown to improve outcomes. [Aronson, 2013]
  • Early recognition of serious bacterial infection is important, however.

Moral of the Morsel

• Most rashes in children are benign, but remain vigilant.
• Eczema injures one of the body’s primary defenses against the outside world, so always consider bacterial as well as viral super-infections.
• If you see blisters in child with eczema, think Eczema Herpeticum!
• Obtain HSV PCR and viral culture of fluid from blisters and initiate acyclovir.

References