she experienced a rash on her torso and back / horrible rash; Caller stated that it looked like small blotches of hives; This is a spontaneous report received from a contactable reporter(s) (Consumer or other non HCP) from medical information team. The reporter is the patient.  A 50 year-old female patient received bnt162b2 (BNT162B2), administered in arm left, administration date 04Mar2021 16:30 (Batch/Lot number: unknown) at the age of 50 years as dose 1, 0.3 ml single for covid-19 immunisation. Relevant medical history included: "Seasonal allergies" (unspecified if ongoing), notes: Lifelong; "Very prone to pneumonia" (unspecified if ongoing), notes: She is very prone to pneumonia. . Concomitant medication(s) included: CETIRIZINE HCL taken for seasonal allergy. The following information was reported: RASH (non-serious) with onset 10Mar2021, outcome "not recovered", described as "she experienced a rash on her torso and back / horrible rash"; URTICARIA (non-serious) with onset Mar2021, outcome "not recovered", described as "Caller stated that it looked like small blotches of hives". The events "she experienced a rash on her torso and back / horrible rash" and "caller stated that it looked like small blotches of hives" were evaluated at the physician office visit. Therapeutic measures were taken as a result of rash, urticaria.  Additional information; It usually starts with seasonal allergies, then becomes respiratory infection and then she ends up with pneumonia. Onset of being very prone to pneumonia was about 22 years ago. first dose of the Covid vaccine on 04Mar in which she experienced a rash on her torso and back. Caller stated that it looked like small blotches of hives and was advised to take Claritin and Benadryl. Caller stated after a week the rash started to look better and lighten up.  Horrible rash: Starting on 10Mar2021, unknown time other than night, she noticed onset of horrible rash on her torso. Starting on 11Mar2021 after she showered she noticed the horrible rash had worsened. The horrible rash is more visually horrible, not really itchy. She thought she had hives, but she had not changed anything. She waited a day and the horrible rash worsened. She called the local health department to see if that is what it is, related to Pfizer-BioNTech Covid-19 Vaccine. They put her over to poison control. Poison control kept following up on her and told her to take Claritin and Benadryl. She started taking Generic for Claritin: Loratadine 10mg in the daytime and generic for Benadryl: Diphenhydramine HCl 25mg at night and the horrible rash seemed to get a little better, but never went away. Description of Product Complaint: Consumer reported horrible rash after 1st Pfizer-BioNTech Covid-19 Vaccine. For horrible rash: Poison control told her to take Claritin and Benadryl. Started generic Claritin: Loratadine 10mg daytime, generic Benadryl: Diphenhydramine HCl 25mg nightly, horrible rash seemed to get little better, never went away. After 2nd Pfizer-BioNTech Covid-19 Vaccine horrible rash worsened. Urgent care advised continue Loratadine, Diphenhydramine HCl, start Pepcid, Hydrocortisone cream even though not itching. Taking generic Pepcid: Famotidine and Hydrocortisone cream. Horrible rash hasn't gotten better. Coloring little better, lighter, but more areas of horrible rash than before, worsened since onset then stayed same pretty much. Famotidine:#brand:20mg daily. Caller reported NDC is tiny number on product: NDC:#,Expiry:Sep2022,Lot: Unknown, but provided numbers above and below expiry:Above:0ME2195B ,Below:19471 2E F8,UPC:Unknown.Diphenhydramine HCl: # brand:25mg tablet nightly, NDC: #,Lot:number above Expiry: P123716,Expiry:Jan2023,UPC:Unknown.Loratadine:Equate #:10mg tablet. Lot: Does not say Lot, but above expiry is:1BE2281A,Expiry:Nov2022,Below expiry:61272 2E F5,NDC:Caller asked could they make this any smaller, already had glasses on: initially thought had two threes:490335 but clarified believes it just has one three:#.UPC: Unknown. Hydrocortisone cream: # brand: NDC:#,Lot:AC14770,Expiry: Dec2023,UPC:Unknown.Mentioned concomitant product Cetirizine HCl 10mg daily for seasonal allergies: Members #,NDC:#Lot:0GE2508A,Expiry:Apr2022,below expiry:4H282 ZY F3.UPC:Unknown.Advised to stop Cetirizine HCl, switch to Claritin, because of something about Zyrtec or Cetirizine HCl inhibitor. Has also taken Dual-Action Advil with Acetaminophen as needed :NDC/UPC: Unknown, does not have box, not on product, Lot: Unknown, number above Expiry is DN7578,Expiry:Mar2023,unknown number:#. No follow-up attempts are possible; information about lot/batch number cannot be obtained. No further information is expected.