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

In response to the coronavirus disease 2019 (COVID-19) pandemic, the COVID-19 vaccine was rapidly developed, and the effectiveness of the vaccine has been established. However, various adverse effects have been reported, including development of autoimmune diseases. We report a case of new-onset polyarteritis nodosa (PAN) in a 32-year-old male following COVID-19 vaccination. The patient developed limb pain, fever, pulmonary embolism, and 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 PAN, similar cases have been reported, and further reports and analyses are therefore necessary.