Recurrence of Pyoderma Gangrenosum Potentially Triggered by COVID-19 Vaccination.

Pyoderma gangrenosum (PG) is a rare inflammatory skin disease of unknown origin. As with other vaccines, COVID-19 vaccines have been associated with many cutaneous reactions. Although COVID-19 vaccination is crucial, it is important for dermatologists and other physicians to be aware of the possible cutaneous reactions that can occur following COVID-19 vaccination. In this report, we describe a 73-year-old woman with a personal history of PG who experienced a recurrence after receiving her second dose of the tozinameran vaccine. Although extremely rare, flares of other inflammatory dermatoses, including lichen planus, have been reported following COVID-19 vaccination. Here we discuss the overlap in pathogenesis of PG and COVID-19, proposing possible mechanisms behind this rare phenomenon.