A 23-year-old active duty US Navy sailor came to our medical center for treatment of 1–2 cm tense pruritic blisters on his dorsal feet, calves, and anterior lower extremities (FIGURE 1). He told us that several days earlier, he had noticed ill-defined “itchy red bumps” on both legs. He denied fever, night sweats, malaise, trauma, insect bites, contact with animals or plants, or recent illnesses. He did say, however, that he’d recently done outdoor fieldwork with the Marine Corps in southern California.
His medical history was unremarkable, and he was not taking any prescribed or over-the-counter medications or supplements. He had no family history of blistering or other autoimmune disorders.
On examination, we noticed clear fluid-filled vesicles and bullae on non-erythematous, non-urticarial bases that were haphazardly distributed on both legs and dorsal feet. Agminated or herpetiform configurations were not present. Ruptured bullae left erythematous to beefy red eroded bases, and there were numerous smaller red papules with vesicular surface changes. All of the lesions were below the knees; there was complete sparing of the trunk, upper extremities, intertriginous skin, head, and neck.
The remainder of the physical examination was unremarkable, and there was no lymphadenopathy. Complete blood count and chemistries were within normal limits, and the patient’s HIV status was negative.
We performed lesional and perilesional punch biopsies. The lesional biopsy demonstrated subepidermal blistering with a predominantly eosinophilic infiltrate in all layers of the dermis and within the blister. Direct immunofluorescence (DIF) was performed on the perilesional biopsy and was negative for IgA, IgG, IgM, C3, and fibrinogen. Gram stain, potassium hydroxide (KOH) prep, and wound culture were also negative.
FIGURE 1
Tense pruritic blisters
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