Matthew Cully, DO
Benjamin F. Jackson, MD
A three-day-old term female infant presented to the emergency department with a two-day history of rash to the back of her right leg. The family noticed the rash shortly after hospital discharge and described the rash first as just a few red spots. However, the following day, the rash spread on her right leg and was now described by the family as multiple red and fluid filled spots. No maternal history of herpes simplex virus (HSV) or varicella at time of delivery. The infant was otherwise well, afebrile with appropriate waking, alertness, appetite, voiding and stooling. On physical examination, she appeared well, active and in no acute distress. A linear, vesicular rash with surrounding erythema extended from right posterior mid shin to upper thigh (Image 1 and 2). Pediatric dermatology was consulted and a full neonatal sepsis evaluation including urine, blood and cerebrospinal fluid (CSF) was performed.
Laboratory investigation including blood culture, urine culture, CSF culture, HSV PCR serum and CSF was negative. Skin fungal culture, bacterial culture, varicella PCR and HSV PCR was negative. Skin biopsy performed by pediatric dermatology was consistent neonatal incontinentia pigmenti. Incontinentia pigmenti is a rare multisystem, X-linked dominant disease.[i] Clinical presentation includes skin, neurologic, ophthalmologic and dental abnormalities. Vesicular lesions typically occur in the first two weeks of life is often mistaken for herpes simplex infection. Incontinentia pigmenti follow Blashko’s lines and should be considered in any female newborn with linear vesicles in the first few weeks after birth after exclusion of infection. [ii]
[i] Okan F, Yapici Z, Bulbul A. Incontinentia pigmenti mimicking a herpes simplex virus infection in the newborn. Childs Nerv Syst 2008; 24: 149-151.
[ii] Rodrigues V, Diamantino F et al. Incontinentia pigmenti in the neonatal period. BMJ Case Rep. Epub 2011 Aug 11.