A 73-year-old man collapsed at home. Ambulance officers noted impalpable blood pressure, shortness of breath and complaints of right-sided chest and epigastric pains.
The man had seen his family doctor earlier that day complaining of sore throat, cough and haemoptysis. He was prescribed cephalexin and had taken the first dose 10 minutes before collapsing. The man had a documented history of amoxycillin allergy with pruritis.
Oxygen and intravenous fluids were given and in the emergency department his blood pressure was 140/70. On examination he had a generalised erythematous rash that was pruritic. Wheeze and tongue swelling were absent and intra-abdominal pathology was excluded. A diagnosis of anaphylaxis to cephalexin was made. Hydrocortisone and antihistamines were given and he was admitted to hospital.
As he was taking propranolol it was ceased, as beta blockers can potentiate further anaphylactic reactions. He remained stable on oral antihistamines and was discharged after three days.
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