Erythema multiforme; drug eruption; viral exanthem; This is a literature report for the following literature source: "Erythema multiforme following mRNA vaccine", 2021.  A 63-year-old female patient received BNT162b2 (BNT162B2), in Mar2021 as dose number unknown, single (Batch/Lot number: unknown) for covid-19 immunisation. The patient's relevant medical history included: "hypothyroid" (unspecified if ongoing); "menopause" (unspecified if ongoing); "COVID-19 infection", start date: Nov2020 (unspecified if ongoing); "hormone replacement" (unspecified if ongoing). Concomitant medication included: SPIRONOLACTONE; LEVOTHYROXINE. The following information was reported: ERYTHEMA MULTIFORME (medically significant) with onset 2021, 24 hrs after the suspect product administration, outcome "recovered"; DRUG ERUPTION (medically significant) with onset 2021, 24 hrs after the suspect product administration, outcome "recovered"; VIRAL RASH (medically significant) with onset 2021, 24 hrs after the suspect product administration, outcome "recovered", described as "viral exanthem". The events "erythema multiforme", "drug eruption" and "viral exanthem" required physician office visit and emergency room visit. The patient underwent the following laboratory tests and procedures: Biopsy skin: focal interface dermatitis, notes: 4 days after vaccine; DDx: early phase of erythema multiforme; Skin test: negative; negative, notes: With saline of 1:100 and 1:10; positive, notes: an 8 x 14 mm wheal and flare (0.02 mL full strength 1:1 vaccine). Therapeutic measures were taken as a result of erythema multiforme, drug eruption, viral rash.  The author evaluated a 63-year-old woman with a history of hypothyroid and menopause on hormone replacement and COVID-19 infection November 2020, who reports 24 hours after receiving Pfizer COVID-19 vaccine in March 2021, developed generalized pruritic, reportedly targetoid lesions on her extremities which progressed to her trunk, only sparing her face. She denies an injection site lesion. She discontinued all chronic medications. She was evaluated and treated serially by her PCP, the ER and dermatology with injected corticosteroids, oral steroid courses, 1st and 2nd generation antihistamines and H2 antagonist, with progressive improvement over 2 weeks. Skin biopsy 4 days after vaccine demonstrated focal interface dermatitis. DDx includes atypical and early phase of erythema multiforme, a drug eruption and viral exanthem. Presentation is complicated by the following: she had started spironolactone and levothyroxine 10 days prior to drug reaction. After dermatitis fully resolved she serially resumed her chronic medications. She resumed spironolactone and levothyroxine approximately 2 months after initial reaction. Within 4 hours she developed facial erythroderma, bilateral conjunctivitis and throat tightening. She self-treated with first and second generation antihistamines, H2 antagonist and oral corticosteroids, with resolution in a few hours. She did not seek medical evaluation. She was seen in follow up 4 months later, when the author was able to secure a small amount of Moderna COVID-19 vaccine for skin testing. Full strength prick 1:1, and ID to dilutions with saline of 1:100 and 1:10 were negative. ID with 0.02 mL full strength 1:1 vaccine was positive with an 8 x 14 mm wheal and flare. Interestingly, the author also performed 1:1 ID on an individual who previously tolerated 2 Moderna COVID-19 vaccines, without an immediate reaction, however the following day, after exercising she developed delayed wheal of 8 x8 mm which progressively enlarged to 30 x 30 mm.