A case report: bullous pemphigoid after a Covid-19 infection

Introduction: Bullous pemphigoid is an autoimmune blistering disease, characterized by large and tense blisters filled with hemorrhagic and hyaline content, that show up on normal skin conditions or over urticarial and intensely pruritic erythematous-edematous lesions It affects mainly elderly individuals after 70 years old and is most frequent in women. SARS-CoV-2 has demonstrated to be an important trigger for autoimmunity, which relation shows up the important role of this viral disease in autoimmunity, the same played by viruses like EBV, CMV, HTLV-1 and others. In the current literature, the incidence of skin manifestations in COVID diseases ranges from less than 1% to more than 20% of patients. Most cases of bullous pemphigoid related to COVID-10 occur as an adverse vaccine reaction, unlike the presented case that describes a patient with bullous pemphigoid after an infectious COVID-19 condition. Objective: To report a case of bullous pemphigoid after COVID-19 infection to provoc a discussion about the physiopathology and case management. Methods: Data for this case report were collected from medical records and test results, authorized by the patient. Result: Female patient, 38 years old, with previous Hashimoto's thyroiditis, sought care at a Dermatology center with blisters in oral mucosal, back, and thoracic regions since a COVID diagnosis 6 months ago. The lesions evolved from papules to vesicles and, after that, to vesicle-pustules. An excisional biopsy was performed, which showed a result of vesiculobullous pattern dermatitis with subepidermal cleft compatible with the clinical hypothesis of bullous pemphigoid. The therapy chosen was prednisone, Dapsone, and folic acid, with dosage adjustments according to disease control and aspect of the lesions. Conclusion: The correlation between bullous pemphigoid and a COVID-19 infection proves the relationship between autoimmune diseases and various viral infections, which is highly related to their physiopathology. Bullous pemphigoid is characterized by IgG autoantibodies against self-antigens of the hemidesmosome from the membrane zone of skin and mucous membranes, making them susceptible to the immune system. On the pathophysiology of COVID-19 infection, occurs, ultimately, an inflammatory reaction by lymphocyte and macrophage activation. Furthermore, the existence of a trigger is a crucial part of the skin's immune attack, which may be related to physical causes, drugs, radiation and, such as the case report, a viral infection. Therefore, is possible to observe the effect of SARS-CoV-2 infection on changing immune expression in predisposed persons and the existence of cutaneous manifestations post-COVID-19 syndrome. Finally, more studies should be done about COVID-19 and extra-pulmonary manifestations and involvement of autoimmune diseases, however, COVID-19 infection may be a trigger for cutaneous manifestations related to autoimmune diseases, as in the case report.