Hypertensive Anaphylaxis After Moderna COVID-19 Vaccination: A Case Report

Hypotension after exposure to an allergen is a well-known indicator of an anaphylactic reaction. However, hypertensive anaphylaxis often goes unrecognized. Increased blood pressure can present as an anaphylactic reaction, which is called hypertensive anaphylaxis. A 48-year-old woman complained of a tickle sensation in the throat and dyspnea 30 minutes after being administered the first dose of the Moderna coronavirus disease 2019 (COVID-19) vaccine. The patient had no history of hypertension, anxiety, or panic disorder. Forty-five minutes after the vaccination, stridor was noted, and the patient developed severe hypertension with a blood pressure of 197/153 mmHg. The patient also had tachycardia, cervical angioedema, and nausea, which occurred in a short period of time, indicating type I hypersensitivity reaction, that is, an anaphylactic reaction. The patient was diagnosed with Brighton classification Level 1 anaphylaxis caused by COVID-19 vaccination. For managing the patient, two intramuscular adrenaline injections, famotidine, chlorpheniramine, metoclopramide, and methylprednisolone were administered via intravenous infusion. After the administration of medications, all symptoms resolved, and the blood pressure was reduced. Other differential diagnoses for increased blood pressure after vaccination were excluded; therefore, we concluded that this phenomenon of increased blood pressure was hypertensive anaphylaxis. Not only hypotension but also the acute onset of increased blood pressure after vaccination may occur as a premonitory symptom of anaphylaxis. In hypertensive anaphylaxis, both anaphylaxis and increased blood pressure can be treated with intramuscular adrenaline injection. Clinicians should be aware of the occurrence of hypertensive anaphylaxis.