Pemphigus Vulgaris After COVID-19: a Case of Induced Autoimmunity

Bullae autoimmune diseases can be induced by environmental factors in a genetically susceptible individual, and viruses may be important triggers for this process. Coronavirus disease 2019 (COVID-19) is a multisystemic disease known for developing many types of skin lesions. However, little is known about post-COVID-19 manifestations. A previous healthy male patient, 43 years old, with resistant mediastinal Hodgkin's lymphoma stage II diagnosed in 2019, without treatment at the moment, developed monomorphic flaccid bullae on the trunk 40 days after testing positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Although he had risk factors for IgA and paraneoplastic pemphigus, there were no elements for these diseases. The investigation confirmed a pemphigus vulgaris (PV). PV had a good response to treatment with prednisolone 1 mg/kg per day, and methotrexate 15 mg subcutaneously was added per week. The patient was discharged with oral methotrexate and prednisolone at the same dose. Prednisolone was decreased by 20 mg per day during the follow-up. Viruses such as herpesvirus, cytomegalovirus, and varicela zoster can act as triggers for PV. This process is not immediate after the infection because it depends on the change in antibodies initially produced against the virus that start to identify antigens present in the skin's anchoring structures. SARS-CoV-2 can induce autoimmunity, as seen in Guillán-Barré syndrome and in Kawasaki disease. It is a highly immunogenic virus that is the perfect agent for triggering PV. This case can be considered a cutaneous autoimmune post-COVID-19 manifestation.