Polyarteritis nodosa diagnosed in a young male after COVID-19 vaccine: A case report.

In response to the coronavirus disease 2019 pandemic, the coronavirus disease 2019 vaccine was rapidly developed and the effectiveness of the vaccine has been established. However, various adverse effects have been reported, including the development of autoimmune diseases. We report a case of new-onset polyarteritis nodosa in a 32-year-old male following the coronavirus disease 2019 vaccination. The patient developed limb pain, fever, pulmonary embolism, multiple subcutaneous nodules, and haematomas. Skin biopsy revealed necrotising inflammation accompanied by fibrinoid necrosis and high inflammatory cell infiltration in the walls of medium to small arteries. The symptoms resolved following corticosteroid treatment. Although it is difficult to prove a relationship between the vaccine and polyarteritis nodosa, similar cases have been reported and further reports and analyses are therefore necessary.