ABSTRACT
Pemphigoid gestationis is a rare autoimmune blistering disorder which typically presents in the second and third trimester of pregnancy. We present an interesting case of a localized flare of the condition following COVID-19 vaccination. A 33- year-old woman presented 2 weeks post partum with an acute onset bullous rash. This had started at week 35 of gestation, one day prior to the onset of labour. A pruritic rash developed on her right arm before becoming widespread, with urticated erythematous plaques and tense bullae. There was no mucous membrane involvement and the infant was unaffected. Skin biopsy showed a prominent perivascular infiltrate with numerous eosinophils, suggestive of pemphigoid gestationis. Uncharacteristically, direct immunofluorescence was negative. Her symptoms improved with 30 mg oral prednisolone and topical clobetasol propionate ointment. She received the first dose of the Pfizer SARS-CoV-2 vaccine 5 weeks after the onset of the rash and within days developed a flare of her rash around the inoculation site. To our knowledge, this is the first report of a flare of pemphigoid gestationis following COVID-19 vaccination. There are case reports of other autoimmune bullous disorders (bullous pemphigoid and pemphigus vulgaris) flaring and occurring de novo following mRNA COVID-19 vaccinations. COVID -19 vaccination has been rapidly rolled out and side-effects in patients with rare conditions are only becoming apparent as these patients are exposed to the vaccine. Knowledge of this side effect will enable us to anticipate it, counsel and treat our patients more effectively, and could help maintain vaccine uptake in this vulnerable patient group. (Figure Presented) .