MRNA COVID-19 VACCINE-ASSOCIATED BULLOUS FIXED DRUG ERUPTION

INTRODUCTION: Fixed drug eruptions are unique cutaneous drug reactions that recur in the same location upon re-exposure to the offending agent. We report a dilemma of how to proceed with the vaccination after a rare complication of the mRNA covid-19 vaccine. CASE DESCRIPTION: A 47-year-old female referred to us after developing a rash to the mRNA covid-19 vaccine for evaluation of safety and plan on how to proceed with the booster vaccine. After the 1(st) dose on her left deltoid, she developed persistent right arm pruritus from mid-forearm to wrist that gradually became well-demarcated and erythematous by day four. Rash improved within seven days of using hydrocortisone but left hyperpigmentation of the skin. Two weeks after receiving her 2(nd) dose on her left deltoid, the same location on her right forearm flared up with more pronounced pruritus, erythema and a few bullous lesions. Rash improved after a week of using hydrocortisone leaving behind hyperpigmentation. The patient denied using any prior medications and had no other skin or mucosal involvement. We decided to proceed with another brand of mRNA covid-19 vaccine instead and prophylactically apply clobetasol twice daily to the affected area for 7-days post-vaccine. She tolerated the vaccine without any flare-up of the rash. DISCUSSION: Fixed drug eruptions more frequently occur with drugs including antimicrobials, NSAIDs, acetaminophen and anti-convulsants. Very rarely has it been reported in association with the administration of the Covid-19 vaccines. This case illustrates a unique predicament after an unusual complication of bullous fixed drug eruption after mRNA covid-19 vaccine administration.