A case of persistent, confluent maculopapular erythema following a COVID-19 mRNA vaccination is possibly associated with the intralesional spike protein expressed by vascular endothelial cells and eccrine glands in the deep dermis

Here, we report an 86-year-old Japanese woman presenting with confluent maculopapular erythema, which developed following the second dose of COVID-19 Messenger RNA (mRNA) vaccine (BNT162b2). Her skin lesions spread over time and persisted for more than 3 months. Surprisingly, immunohistochemical staining of the lesion 100 days after the disease onset revealed the COVID-19 spike protein expressed by vascular endothelial cells and eccrine glands in the deep dermis. As she had no episode of COVID-19 infection, it is highly likely that the spike protein was derived from the mRNA vaccine and it might be the cause of the development and persistence of her skin lesions. Her symptoms were prolonged and intractable until oral prednisolone was given.