A patient on penicillin develops hives and facial swelling. What is the immediate action?

• A. Stop penicillin; assess for anaphylaxis; administer epinephrine if signs of anaphylaxis; summon help.
• B. Continue penicillin and monitor for worsening symptoms.
• C. Administer antihistamines and resume penicillin.
• D. Switch to a different antibiotic without allergy testing.

Answer: (A)

Recognizing a possible anaphylactic reaction to penicillin and acting immediately is the key idea here. When hives and facial swelling appear after antibiotic exposure, there’s a real risk of progression to airway obstruction and shock, so the first steps are to stop the offending drug and assess the patient’s airway, breathing, and circulation.

If there are signs of anaphylaxis, epinephrine is the essential treatment and should be given right away—typically an intramuscular injection into the mid-outer thigh (0.3–0.5 mg of a 1:1000 solution for adults), with the dose repeatable every 5–15 minutes as needed. While this is being done, summon help and arrange for emergency care. Keep the patient in a position that supports breathing (usually supine with legs elevated unless there is severe breathing difficulty), provide oxygen if available, and continuously monitor vital signs.

Do not continue penicillin or switch to another antibiotic without allergy assessment, and antihistamines alone do not treat anaphylaxis adequately. After stability is achieved, document the reaction, advise avoidance of penicillin-family drugs, and consider formal allergy testing.