10 day old neonatal girl presents with parents with concern for a rash along her scalp

Obtain IV access and perform a full neonatal septic work-up, including blood cultures, urine cultures and cerebrospinal fluid cultures and start the infant on IV antibiotics.

This infant is presenting with skin findings concerning for HSV.  Scalp monitors can cause minor trauma to the skin, which can serve as a focal point for transmission of herpes virus.  Neonatal herpes is most common in the first 3 weeks of life, especially between weeks 2-3.  There are 3 typical presentations of neonatal HSV: 1. Localized skin, eye and/or mouth disease, with no visceral or CNS involvement. 2. Localized CNS disease with fever, seizures and altered mental status and 3. Disseminated disease with multisystem involvement.   HSV can present as skin vesicles on a shallow erythematous base, sometimes in clusters.  The presence of skin vesicles, temperature instability or seizure activity should all raise the possibility of a neonatal HSV infection.  All infants with concern for neonatal HSV should have a full septic workup and empirically begin IV acyclovir until culture results are negative.

There are many newborn rashes that are common and require no further work-up, but the presence of vesicles is concerning for HSV.  Olive oil and a comb are often used for treatment of seborrheic dermatitis, also known as cradle cap. Topical mupirocin, an antibiotic, is not effective against HSV.  Eosinophilia is seen on skin biopsies of infants who present with erythema toxicum.  Erythema toxicum lesions are erythematous macules and papules that may progress to pustules on an erythematous base. They often appear diffusely on an infant’s skin but do not cluster and are not vesicular.  [F&L pp 998]