could not swallow; hyped up on prednisolone; chect pain pain (deep esophageal); chest pain (deep esophageal)./went to ER; unable to turn her head/went to ER; pain; itching; hives on head, neck, ears, face and chest/went to ER; biphasic anaphylactic response; intense fever; This case was reported by a consumer via call center representative and described the occurrence of biphasic anaphylactic reaction in a 63-year-old female patient who received Flu Seasonal QIV Dresden (Fluarix Quadrivalent 2022-2023 season) (batch number as5rm, expiry date unknown) for prophylaxis.   Co-suspect products included flu seasonal qiv dresden pre-filled syringe device (Fluarix Tetra Pre-Filled Syringe Device) injection syringe for prophylaxis, prednisolone for pain and morphine for pain.   Concurrent medical conditions included egg allergy.   On 10th December 2022, the patient received Fluarix Quadrivalent 2022-2023 season (intramuscular) and Fluarix Tetra Pre-Filled Syringe Device. In December 2022, the patient started prednisolone 50 mg at an unknown frequency and morphine at an unknown dose and frequency. On 10th December 2022, less than a day after receiving Fluarix Quadrivalent 2022-2023 season and Fluarix Tetra Pre-Filled Syringe Device, the patient experienced biphasic anaphylactic reaction (serious criteria GSK medically significant) and fever. On 12th December 2022, the patient experienced pruritus and hives. On 13th December 2022, the patient experienced chest pain, mobility decreased, pain and esophageal pain. On 14th December 2022, the patient experienced behavior hyperactive. On 15th December 2022, the patient experienced unable to swallow. The patient was treated with epinephrin, epinephrine (Epi Pen), medication unknown (Fluids) and benadryl (nos) (Benadryl). The action taken with prednisolone was unknown. The action taken with morphine was unknown. On an unknown date, the outcome of the biphasic anaphylactic reaction, fever, pruritus, chest pain, mobility decreased, pain, behavior hyperactive, unable to swallow and esophageal pain were recovering/resolving and the outcome of the hives was not recovered/not resolved.   The reporter considered the biphasic anaphylactic reaction to be related to Fluarix Quadrivalent 2022-2023 season. It was unknown if the reporter considered the fever, pruritus, hives, chest pain, mobility decreased, pain, behavior hyperactive, unable to swallow and esophageal pain to be related to Fluarix Quadrivalent 2022-2023 season and Fluarix Tetra Pre-Filled Syringe Device. It was unknown if the reporter considered the biphasic anaphylactic reaction to be related to Fluarix Tetra Pre-Filled Syringe Device.   This report is made by GSK without prejudice and does not imply any admission or liability for the incident or its consequences.   Additional Information: GSK receipt date: 05 JAN 2023 Reporters comment:  The patient was the reporter. The patient received Patient received Fluarix on 10th December 2022. The patient experienced a biphasic anaphylactic response after getting the fluarix vaccine, patient reports on the evening of 10th December 2022 had an intense fever that lasted 30 hours. The patient said the following Monday morning 12th December 2022 felt better but by monday afternoon the patient started itching and was covered in hives by Monday night. The patient reported was  taking 2 Benadryl every 4 hours as per her physicians orders.  Patient said the next day 13th December 2022 continued to have hives and now had chest pain deep esophageal. Patient said her hives were present on the back of her head and neck. She said she was unable to turn her head. Patient reports going to the emergency room and received fluids and intravenous Benadryl, also had a chest x-ray , electrocardiogram, and blood work done which were all negative.  The patient reported that she had a negative Respiratory syncytial virus test, flu and covid test in the hospital, also reports receiving morphine in the hospital for pain. The patient was then sent home with 50 mg of prednisolone. The patient said the next day  14th December 2022 felt better and was hyped up on prednisolone and continuing to take Benadryl for the hives, errands that day. The patient reported next morning that is 15th December 2022 hives were on her neck, ears, face and front of her chest. also reported that she could not swallow as well still taking Benadryl and prednisolone took an ambulance to the emergency room and received fluids and a Epi-shot and was given an Epi-pen to travel with.  The patient was then sent home from the emergency room after four hours and has been recovering, hives are still present and she is still taking prednisolone. Reporter consented to follow up. It was unknown if reporter consider the events chest pain, esophegal pain mobility decreased, pain, behavior hyperactive and unable to swallow related to Benadryl and Benadryl IV. It was unknown if the reporter consider the pain, behavior hyperactive and unable to swallow related to morphine. It was unknown reporter consider the behavior hyperactive and unable to swallow related to prednisolon. Additional supportive information: Due to tempral relation the treatment products  prednisolon, morphin, Benadryl and Benadryl IV considered as cosuspect conservatively.