An 8-year-old girl with a 4-year history of chronic intermittent eruption of a pustular rash on her torso presented for evaluation in the dermatology clinic with an ongoing flare. The current rash had persisted despite the application of topical fluocinonide, topical clobetasol, a selenium sulfide wash, and oral cephalexin.
Laboratory test findings were significant for a neutrophilic leukocytosis (14,200 white blood cells/µL). Histologic review of a punch biopsy specimen demonstrated an epidermal and superficial perivascular neutrophilic infiltrate with overlying serum crust. Results of Grocott methenamine silver and periodic acid–Schiff stains were unremarkable.
The results of further evaluation with a basic metabolic panel, serologic testing for hepatitis B, and purified protein derivative skin testing for tuberculosis were normal or negative. Based on her presentation and laboratory test results, the patient received a diagnosis of pustular psoriasis (Figures 1 and 2).