key: cord-0828717-1vippkpc authors: Pérez-López, Israel; Moyano-Bueno, David; Ruiz-Villaverde, Ricardo title: Bullous pemphigoid and COVID-19 vaccine() date: 2021-10-21 journal: Med Clin (Engl Ed) DOI: 10.1016/j.medcle.2021.05.004 sha: d55200a0bed9af360875d27838180e09cd2fc64b doc_id: 828717 cord_uid: 1vippkpc nan This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Letter to the Editor Bullous pemphigoid (BP) is an autoimmune skin disease characterized by the appearance of tense blisters over an erythematous base and the existence of circulating G immunoglobulins (IgGs) against hemidesmosome antigens BP180 and BP230. 1 In this paper we present the case of a woman who developed BP after receiving the first dose of COMIRNATY (messenger ribonucleic acid [RNAm] Pfizer-BioNTech vaccine) and a subsequent reactivation after receiving the second one. The case corresponds to a 78-year-old woman with diabetes mellitus, treated with insulin, and Alzheimer's disease (global deterioration scale [GDS] score of 4), treated with memantine. She consulted the Dermatology Department due to a 1.5-month history of skin rash, reporting that the lesions had appeared three days after she received the COMIRNATY vaccine. Her symptoms stabilized within two weeks with the aid of high-potency topical corticosteroids. However, 21 days later, she experienced a significant reactivation after receiving the second dose of the vaccine (Fig. 1) . A physical examination revealed tense blisters over an erythematous base on her face, trunk, and limbs. No lesions were detected on any of her mucous surfaces. A skin biopsy confirmed the diagnosis of BP, with both direct and indirect positive serum immunofluorescence. The remaining laboratory analyses yielded normal results, except for mild eosinophilia. We informed the Pharmacovigilance System and started treatment with prednisone 40 mg every 24 hours, achieving a good clinical response. The two BP antigens are found in the hemidesmosome, a cell adhesion complex that anchors the epithelium to the basement membrane. It has been proposed that IgG bound to these antigens activates the complement by inducing inflation and interrupting this bond. 2 Genetic predisposition and certain triggering factors are involved in its etiopathogenesis. The association between BP and basement membrane alterations, such as traumas or burns; certain drugs, such as oral antidiabetics; or neurological diseases, such as Parkinson's disease or dementia, is well known. 2,3 The latter association is partly explained by the autoimmune cross-reaction that occurs between the BP230 protein isoforms present in both the skin and the central nervous system. 2 In relation to vaccines, cases of BP have been reported following the administration of vials against tetanus, diphtheria, pertussis, polio, rabies, hepatitis B, rotavirus, pneumococcus, or influenza. [1] [2] [3] [4] [5] The latency period ranges between one day (or earlier in the case of the pediatric population) 1 and one month following the vaccination. 2, 4, 5 The mechanism by which the vaccine induces BP is not well understood, and it is unlikely that a vaccine itself would explain the association, as there are no similarities between the vaccine structure and the basement membrane antigens. 2 One hypothesis that has previously been proposed is that the vaccination may trigger a greater autoimmune response in patients with a significant immunological predisposition, 2,4 such as the case of our patient with Alzheimer's disease, as the vaccine would activate B-cell immunity and, therefore, the production of antibodies, 4 which is the main mechanism by which the lesions of this disease are generated. In our patient, BP developed within three days of the administration of the first dose of the COMIRNATY vaccine against the 2019 coronavirus disease (COVID-19) . The appearance of these et all. Postvaccination Bullous Pemphigoid in Infancy: Report of Three New Cases and Literature Review Bullous pemphigoid triggered by rabies vaccine Bullous pemphigoid triggered by influenza vaccination? Ecological study in Galicia, Spain Bullous pemphigoid triggered by swine flu vaccination: case report and review of vaccine triggered pemphigoid Infantile bullous pemphigoid following serogroup B meningococcal vaccination Figure 1. Tense blisters with serous contents over a slightly erythematous base of urticariform morphology 1. Ampollas tensas de contenido seroso sobre una base levemente eritematosa de morfología urticarial.