Crawling Toward a Diagnosis: Vesicles and Thrombocytopenia in a Neonate

Case

A previously healthy 25-day-old boy presented to a tertiary children’s hospital with a diffuse vesicular rash worsening over the previous 2 weeks. Per parental report, the rash was not accompanied by any other symptoms and did not appear to be pruritic or painful; specifically, he had no history of fever and was formula feeding well. The infant was the product of a full-term pregnancy, complicated only by a maternal diagnosis of pruritic papules and plaques of pregnancy at ∼34 weeks of gestation. There was no known maternal history of herpes simplex virus (HSV) infection, and the mother denied any recent personal or family history of rashes or other skin lesions. The infant did not have any known allergies and no offending topical agent could be identified from the parental interview. He was not taking any medications.

What Are Key History Points That Must Be Considered When Presented With a Vesicular and Pustular Rash in a Neonate?

This differential includes both relatively benign conditions and diseases associated with significant morbidity and mortality. Key history points include pertinent birth events, maternal health status, onset timing of the rash, presence of systemic symptoms, such as fever or poor feeding, location of rash, potential allergen exposure, contacts with similar rashes, trauma to the skin, and family history of skin diseases. The duration of the rash is important because a well-appearing infant with a rash of 2 weeks’ duration is less concerning than a febrile infant who developed vesicles 24 hours prior.

On physical examination, the infant was fussy but consolable when held. He was afebrile with vital signs within the normal limits for his age. Examination was otherwise unremarkable except for vesicles on an erythematous base and pustules on the face, torso, extremities, soles, hands, palms, and occipital scalp (Fig 1). There were no interdigital lesions, and his mucous membranes were lesion-free. Neurologic examination showed no focal abnormalities.