Flaccid pustules and vesicles in a middle-aged woman

Abstract

A 60-year-old woman presented with a pruritic abdominal rash. Physical examination revealed multiple non folliculocentric pustules and vesicles, 4-10 mm in size with a localized surrounding rim of erythema localized to the left abdomen. The patient was treated with a 7-day course of valaciclovir for presumed varicella zoster viral (VZV) infection but the symptoms worsened. She was on no other new medications. Upon re-examination, a widespread eruption of flaccid pustules was seen on the abdomen (Fig. 1), anterior thighs and antecubital fossa. The mucosal membranes were uninvolved. Swabs for herpes simplex virus and VZV qualitative PCR testing were negative, and Tzanck smears demonstrated no multinucleated giant cells. Bacterial cultures were also negative. Histopathological findingsHistopathological evaluation of a punch biopsy specimen demonstrated a subcorneal blister with associated superficial epidermal acantholysis ( Fig. 2a) and accumulation of neutrophils within the blister cavity (Fig. 2b). Direct immunofluorescence studies were negative for deposition of IgG, IgA, IgM, C3, and fibrinogen.What is your diagnosis? (a) (b) Figure 2 (a) Subcorneal blister with associated superficial epidermal acantholysis; (b) neutrophils within the subcorneal blister cavity. Haematoxylin and eosin, original magnification (a) 9 100; (b)9 400.Figure 1 Non folliculocentric pustules with a surrounding rim of erythema localized to the left abdomen.ª