Bullous pemphigoid after SARS‐CoV‐2 vaccination: spike‐protein‐directed immunofluorescence confocal microscopy and T‐cell‐receptor studies

Dear Editor, Growing evidence suggests that SARS‐CoV‐2 vaccination is associated with a variety of cutaneous reactions. These include autoimmune‐mediated conditions such as autoimmune blistering diseases (AIBDs), one of which is bullous pemphigoid (BP).1, 2 We report new‐onset BP in two patients following their first SARS‐CoV‐2 vaccination. The first patient was an 80‐year‐old man who noticed reddish itchy macules with small blisters on his lower legs 1 week after vaccination with BTN162b2.2 Two weeks later, after he had received his second shot, these erythematous/bullous lesions spread over his trunk (Figure 1a). The second patient was an 89‐year‐old man who noticed 2 days after the first BTN162b2 vaccination itchy erythematous/bullous lesions on his entire integument. Neither of the patients reported intake of any new medications or other newly diagnosed conditions prior to the AIBDs. In both cases, subepidermal clefts were demonstrated on routine histology (Figure 1b). In both patients, direct immunofluorescence on frozen sections revealed linear deposits of IgG and C3 at the basement membrane zone. Indirect immunofluorescence showed bandlike IgG deposits on the epidermal side in both patients. In both cases, enzyme‐linked immunosorbent assay revealed highly elevated autoantibody levels against BP‐180 (365 U mL−1 and 115 U mL−1, normal range < 20) and BP‐230 (223 U mL−1 and 41 U mL−1, normal range < 20). Hence, both patients were diagnosed with BP. Both were successfully treated with a tapered systemic prednisolone regimen.