Abstract

Acute febrile neutrophilic dermatosis or sweet syndrome is characterized by abrupt onset of fever, leukocytosis and tender erythematous plaques that resolve with corticosteroids. This condition typically presents in adults with 5% of cases presenting in the pediatric population. We present a case of a 5-week-old female born at 35 weeks due to maternal preeclampsia who presented with fever and multiple erythematous edematous annular plaques on the neck, extremities and buttocks. There was no family history of autoimmune disorders. Laboratory work up was notable for leukocytosis, anemia, thrombocytosis and elevated C-reactive protein. Punch biopsy of the neck demonstrated an unremarkable epidermis with papillary dermal edema and a dermal inflammatory infiltrate predominated by neutrophils and occasional eosinophils. Leukocytoclasis was noted, however there was no evidence of vascular damage and infectious workup was negative for bacterial, fungal and acid-fast organisms. The histologic differential diagnosis included sweet syndrome, neutrophilic figurate erythema of infancy and chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperature (CANDLE) syndrome. Additional work up for infection, malignancy, primary immune deficiencies, autoimmune disorders, inflammatory bowel disease and autoinflammatory diseases such as CANDLE syndrome were all negative. The patient was started on prednisone which led to the rapid resolution of the rash. Neonatal sweet syndrome is exceedingly rare with only 20 reported cases in the literature. Presentation in the first 6 weeks of life can be associated with an underlying systemic or genetic association, whereas a viral etiology is more likely in infants older than 3 months. With variable underlying etiologies and a paucity of reported cases in the literature, our report adds to the current literature of neonatal sweet syndrome as a clinicopathologic entity.

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