Anaphylaxis with Hypertension – A Rare Manifestation: Two Case Reports

Anaphylaxis is a severe, potentially fatal hypersensitivity reaction that classically presents with hypotension due to distributive shock. Hypertension during anaphylaxis is rarely reported and may lead to diagnostic uncertainty or delay in treatment.
We describe two patients with anaphylaxis manifesting predominantly as hypertension with tachycardia. The first, a 43-year-old man, developed dizziness, palpitations, and marked hypertension with tachycardia minutes after receiving the AstraZeneca COVID-19 vaccine. The second, a 56-year-old man with leptospirosis, developed urticaria, stridor, and hypertension immediately after starting intravenous ceftriaxone. Both patients improved rapidly with intramuscular adrenaline, oxygen, and supportive care. Serum tryptase level was elevated in the first case, supporting the diagnosis.
These cases highlight that anaphylaxis can rarely present with hypertension instead of hypotension. Clinicians and anaesthetists must maintain a high index of suspicion, as early recognition and adrenaline administration remain lifesaving regardless of blood pressure status.