Angioedema; Urticaria returned and became widespread; Urticaria after 4 hours under each arm; This spontaneous case was received on 12-Jan-2023 from other non-healthcare professional (consumer) via Agency (reference number: SEQW23-00175) with additional information received on 13-Jan-2023 (being processed together) and concerned a 46-year-old, male patient.   The patient had no relevant medical history and was healthy. The patient's concomitant medications were not reported.   On 06-Oct-2022, the patient was vaccinated with Afluria Quadrivalent (influenza vaccine inact split 4v; dose: 0.5 ml, route of administration: intramuscular, anatomical location: not reported) for prevention of influenza disease. The batch number reported was P100468911 and expiry date: 30-Jun-2023.   On the same date, four hours after receiving Afluria Quadrivalent, the patient experienced minor initial reaction of urticaria under each arm.   On 08-Oct-2022, the patient recovered from the event of urticaria. It resolved within 48 hours.  On 11-Oct-2022, three days later, urticaria returned and became widespread and severe and was accompanied by significant angioedema which ultimately required a trip to the emergency room.  On 12-Oct-2022, the patient went to the emergency room and received epinephrine, methylprednisolone and diphenhydramine which resolved the symptoms.  On the same date, the patient recovered from the events of urticaria and angioedema.   The reporter assessed the events as related to Afluria Quadrivalent, as it was reported as adverse reaction to Afluria Quadrivalent vaccine. Patient stated that after consulting with his doctor and seeing an allergist, it sounded like it was quite rare to have a delayed onset of symptoms of this significant nature.  The event of angioedema was considered to be medically significant by a Physician within Seqirus's Pharmacovigilance and Risk Management Department.  Company comment: A 46-year-old, male patient was vaccinated with the suspect product Afluria Quadrivalent. On the same day the patient developed minor initial reaction of urticaria under each arm (as reported), which lasted for 48 hours. Five days after vaccination urticaria returned and became widespread and was accompanied by significant angioedema. Information regarding the related diagnostic findings was not provided. The patient had no relevant medical history and was healthy. The patient's concomitant medications were not reported. Based on plausible temporal relationship, causality for the two episodes of urticaria and angioedema is assessed as possibly related.; Reporter's Comments: Adverse reaction to Afluria Quadrivalent vaccine.; Sender's Comments: A 46-year-old, male patient was vaccinated with the suspect product Afluria Quadrivalent. On the same day the patient developed minor initial reaction of urticaria under each arm (as reported), which lasted for 48 hours. Five days after vaccination urticaria returned and became widespread and was accompanied by significant angioedema. Information regarding the related diagnostic findings was not provided. The patient had no relevant medical history and was healthy. The patient's concomitant medications were not reported. Based on plausible temporal relationship, causality for the two episodes of urticaria and angioedema is assessed as possibly related.