Bullous pemphigoid after second dose of mRNA- (Pfizer-BioNTech) Covid-19 vaccine: A case report

Messenger RNA vaccines, commonly known as mRNA vaccines, are the first COVID-19 vaccines that have been authorized and licensed in the United States. Two mRNA vaccines, BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna) are available. Mass vaccination remains the most critical way to halt the spread of the COVID pandemic. The most common adverse effects of the COVID vaccines are headache, muscular soreness, weariness, redness, swelling, and tenderness at the injection site. The dermatological adverse effects of mRNA vaccines, on the other hand, are little understood. We present a case of bullous fixed medication eruption following delivery of the second dose of Pfizer's Covid-19 vaccination. We discuss the case of a 78-year-old man who went to the Emergency Department at King Fahad Medical City in Riyadh, Saudi Arabia, with numerous bullae throughout his extremities one day after receiving the second dosage of Pfizer Covid-19 vaccine. The bullae began three days before his presentation, and they were preceded by intense pruritus and urticated plaques. A skin biopsy was performed which revealed IgG (+1), IgM (+1), and C3 (+1) staining of the basement membrane. Another punch skin biopsy taken from an intact bulla was suboptimal compressing of dermal tissue only, revealing modest perivascular lymphocytic infiltrative and scattered eosinophils. This pathological picture with superficial perivascular inflammatory dermatitis, and the presence of eosinophils suggests drug-induced bullous pemphigoid. The patient was treated with topical and systemic corticosteroids, fusidic acid cream, and emollients after a confirmed diagnosis of bullous pemphigoid was obtained. He was hospitalized for 3 weeks as a case of severe sepsis due to a skin infection, and he was started initially on empiric antibiotics with piperacillin-tazobactam plus vancomycin that was later upgraded to meropenem and vancomycin based on the results of the blood and wound cultures. The patient suffered a pulmonary embolism on the second day of hospitalization and was placed on a heparin infusion that could potentially contribute to his death one month after discharge from our hospital. Bullous pemphigoid is the most frequent autoimmune bullous disease. It occurs in the elderly. The cause of this disease is unknown, although it sometimes can be triggered by taking certain medications. Two case reports have also revealed bullous pemphigoid eruption following immunization. One case report reported a 78-y