feels like a million bumps on the backs of her legs; my arm was tender and sore; rash/Leg rashes were behind my knee and extended up back of legs; my arm was tender and sore; within 24 hours of receiving the shot she started itching; backs of her knees and the backs of her thighs on both legs had these welts on them/ noticed some little welts on her arms and upper portion of her abdomen/ notices the welts also starting to come up on her inner thighs; This is a spontaneous report received from contactable reporter(s) (Other HCP). The reporter is the patient.  A 76 year-old female patient received bnt162b2 (BNT162B2), intramuscular, administered in arm right, administration date 25Oct2021 13:00 (Lot number: 32308B) at the age of 76 years as dose 3 (booster), single for covid-19 immunisation. Relevant medical history included: "High blood pressure" (unspecified if ongoing), notes: Why was the patient taking Pfizer Covid Vaccine (Verbatim): High blood pressure; "sneeze" (unspecified if ongoing). Concomitant medication(s) included: VALSARTAN; VITAMIN B12 [CYANOCOBALAMIN]; CALCIUM; CINNAMON; FLU VACCINE VII, start date: Sep2021, stop date: Sep2021. Vaccination history included: Bnt162b2 (First Dose of the Pfizer Covid Vaccine: Given on 02Feb2021; Lot Number: Reported as being either FL3302 or EL3302 by the caller; Given in the caller's left arm., Dose: 1st, Date/time: Date: 02Feb2021, Time: 12:15 , Site and route of injection: Anatomical site of location: Left bicep, Route of administration: Intramuscular, Batch/Lot number: Pfizer EL3302), administration date: 02Feb2021, when the patient was 75 years old, for Covid-19 immunization, reaction(s): "tenderness in her left arm"; Bnt162b2 (Dose: 2nd, Lot number: EM9810, location: Arm left, Dose: 2nd, Date/time: Date: 23Feb2021, Time: 12:15 , Site and route of injection: Anatomical site of location: Left bicep, Route of administration: Intramuscular, Batch/Lot number: Pfizer EM9810), administration date: 23Feb2021, when the patient was 75 years old, for Covid-19 immunization, reaction(s): "tenderness in her left arm", "made her want to sleep". The following information was reported: PRURITUS (non-serious) with onset 26Oct2021, outcome "recovered", described as "within 24 hours of receiving the shot she started itching"; URTICARIA (non-serious) with onset 26Oct2021, outcome "recovered", described as "backs of her knees and the backs of her thighs on both legs had these welts on them/ noticed some little welts on her arms and upper portion of her abdomen/ notices the welts also starting to come up on her inner thighs"; SKIN DISORDER (non-serious), outcome "recovered", described as "feels like a million bumps on the backs of her legs"; TENDERNESS (non-serious), PAIN IN EXTREMITY (non-serious) all with onset 26Oct2021, outcome "recovered" and all described as "my arm was tender and sore"; RASH (non-serious) with onset 26Oct2021, outcome "recovering", described as "rash/Leg rashes were behind my knee and extended up back of legs". Therapeutic measures were taken as a result of pruritus, urticaria, tenderness, rash, pain in extremity. Therapeutic measures were not taken as a result of skin disorder.  Reporter consider the Pfizer product had a causal effect to the adverse event.  Additional information: Patient did not receive additional vaccines administered on same date of the pfizer suspect. Patient did not receive any prior vaccinations within 4 weeks. Patient received prednisone 20 mg, Benadryl 25 mg for the treatment of the event rash and itch. Clinical course: It was reported that that patient received her first two doses of the Pfizer Covid Vaccine in February. She got the booster dose on Monday. Yesterday within 24 hours of receiving the shot she started itching. When she got home, she noticed that the backs of her knees and the backs of her thighs on both legs had these welts on them. States that she put some cream and a bandaid on them which helped with the itching. In the morning she noticed some little welts on her arms and upper portion of her abdomen. States they are not bad like the ones behind her legs. She went back to pharmacy and spoke with the pharmacist who stated they did not know what it could be. The pharmacist advised the caller to report these symptoms to Pfizer. Patient was sitting she notices the welts also starting to come up on her inner thighs. Says she does not know what it is, it feels like a million bumps on the backs of her legs. Patient states she does not feel it is serious or life threatening. States not unless she is going to itch herself to death and then laughs. Her first two vaccines were two weeks apart and she had no real issues other than the second dose made her want to sleep. Patient states that she can't think of anything else that may have caused her symptoms. Says she has not changed anything. Patient denies any other medications or medical conditions relevant to these events. Then states that she takes valsartan, vitamin B12, calcium, and cinnamon. She has been taking these for years and she does not feel they are relevant. Only other thing she knows is that she cannot drink certain drinks because they make her sneeze. She doesn't think that it is an allergy; she just doesn't drink them so that she won't sneeze. Patient arm was tender and sore on the 26Oct2021 in evening, noticed and felt welt and rash with terrible itching. On 27Oct2021 went to pharmacy and spoke to pharmacist that had given injection and described rash. At that time was starting on inner aspect of left elbow. Leg rashes were behind knee and extended up back of legs. Received paper to call Pfizer with reaction. On 29Oct2021 noticed MD ordered prednisone 20 mg 7 days, also used a cream for itching, rash has slowly gone away. As of 7Nov2021, no rash or itching. Used triamcinolone cream for itch. 08Nov2021 still small area of rash.  No follow-up attempts are possible. No further information is expected.