Wrong Place at the Right Height: Scalp Orf in a Toddler With Dense Dermal Neutrophilic Infiltrate Mimicking Sweet Syndrome.

Abstract

We report a case of a 3-year-old male who presented with fever, posterior cervical lymphadenopathy, and a tender vesiculobullous lesion on the scalp following contact with goats 2 weeks prior. Histopathology revealed epidermal necrosis, massive papillary dermal edema, brisk mixed inflammation with abundant neutrophils, and inclusion bodies in the epidermis. These findings led to a diagnosis of orf virus infection, otherwise known as ecthyma contagiosum, which is a parapox virus acquired from goats and sheep. An abundance of neutrophils is not a feature classically thought to be associated with orf virus. Additionally, orf typically affects the hands following direct contact with infected animals; the scalp is an unusual site of infection. We suspect infection occurred as this child's scalp when standing was roughly the same height as a goat's mouth, and goats have a predilection to chew at hair. Unfortunately, despite extensive attempts, we were unable to find any laboratory that offers molecular testing for orf on formalin-fixed paraffin-embedded tissue samples. Because of the lack of readily available molecular testing for this infection, we seek to highlight the importance of considering orf in the differential diagnosis of vesicular lesions and obtaining animal exposure history to aid in this diagnosis.