GP has diagnosed as erythema multiforme; Skin in my arms seems to be drying out a bit and swelling down; still in a fair amount of pain; Slept a lot of the day; Upper arms and hands red, sore and swollen; rash covered and warm to the touch; skin feel tingly like a rash coming on; chills; Upper arms and hands red, sore and swollen; Upper arms and hands red, sore and swollen; rash covered and warm to the touch; felt tired; This is a spontaneous report from a contactable Consumer (patient). A 60-year-old non-pregnant female patient received BNT162B2 ((PFIZER-BIONTECH COVID-19 VACCINE, formulation: Solution for injection, Lot Number: ER8733), via an unspecified route of administration in left arm on 31Mar2021 at 09:30 (Age at vaccination was 60-year-old) as dose 2, single for COVID-19 immunization. The patient medical history included polycythaemia vera from an unknown date and unknown if ongoing. Concomitant medications included Losartan, Hydroxyurea and Anagrelide all taken for an unspecified indication, start and stop date were not reported (other Medications in Two weeks). She did not receive any other vaccine in four weeks prior vaccination. She was not diagnosed with COVID prior vaccination and not tested with COVID post vaccination. She had no Known allergies. The patient previously received BNT162B2 (PFIZER-BIONTECH COVID-19 VACCINE, formulation: Solution for injection, Batch/Lot Number was not reported), via an unspecified route of administration, administered in Arm Left on 10Mar2021 as (Age at Vaccination 60-year-old) dose 1, single for COVID-19 immunization and on 19Mar2021 at 6:00 patient experienced started to get rash on upper left arm-shot arm, rash spread to upper right arm and a few spots on her knees, blood draw. Platelets almost doubled since her last count three weeks prior. Increase Anagrelide to two pills twice a day. On 01Apr2021 patient felt tired, 02Apr2021 really feel tired and skin feel tingly like a rash coming on. Had chills. By evening upper arms were red, sore, swollen, rash covered and warm to the touch, on 03Apr2021, Slept a lot of the day and still in a fair amount of pain. Upper arms and hands red, sore and swollen. Took an over-the-counter antihistamine Zyrtec, which helped with the swelling. On 04Apr2021, continued with Zyrtec, 05Apr2021, continued with the Zyrtec. Skin in my arms seems to be drying out a bit and swelling down. On 06Apr2021, Arms and hand still red but swelling down. GP has diagnosed as erythema multiforme. The patient has visited physician office as result of events. The seriousness of the event erythema multiforme was serious and medically significant. The seriousness of the other events was non-serious. Therapeutic measures were taken as a result of events includes Topical Cream and took an over-the-counter antihistamine Zyrtec, which helped with the swelling on 03Apr2021. The patient underwent lab tests and procedures which included blood draw: platelet count increased (Platelets almost doubled since her last count three weeks prior) on 23Mar2021. The outcome of the event by evening upper arms were red (erythema) was not recovered. The outcome of all the remaining events was recovering.  No follow-up attempts are needed. No further information is expected.; Sender's Comments: Linked Report(s) : US-PFIZER INC-2021381274 similar report from same reporter