Case report:
A 55-year-old man attended our dermatology department complaining of painful blisters on his hands and feet, that insidiously appeared over a one-month period. He had no medical history of dermatologic or auto-immune diseases. Pruritus of hands and feet first appeared four days after the first dose of the Pfizer BioNTech COVID-19 vaccine, then blisters appeared after the second dose, received one month later. Physical examination revealed clustered vesicles and tense bullae, mainly distributed on upper and lower extremities with crusted erosions on the elbows and the forearms. Lesions with a target-like appearance were seen on the back of the hands (Fig 1: a,b,c). There was no mucosal involvement. The Nikolsky sign was negative. The laboratory test results were within normal limits, including complete blood count and blood chemistry profile. Skin biopsy was performed showing subepidermal blister with lymphocytic and eosinophilic infiltrate, spongiosis and dermal edema. Direct immunofluorescence study revealed linear band of IgG and C3 along the dermo–epidermal junction confirming the diagnosis of BP (Fig 2: a,b,c). Pharmacovigilance imputability score was I1B2. Given the severity of the cutaneous reaction, oral prednisone was started at 0.5 mg/kg/day with rapid clinical improvement.