A patient returns after a biopsy with marked swelling of the lip. What is the most likely diagnosis?

Correct answer: B. Angioedema

• A. Normal post-operative oedema is proportionate to the size of the procedure, localised to the site, and peaks at 48 to 72 hours. A marked, diffuse lip swelling out of proportion to a small biopsy is not normal healing.
• B. CORRECT. Angioedema is a rapid, non-pitting, poorly demarcated swelling of the deep dermis and submucosa, and the lips are among its most characteristic sites. In a post-biopsy patient the likely triggers are the local anaesthetic or its preservative, a topical antiseptic, latex, or an analgesic or antibiotic prescribed afterward. The critical clinical point is that angioedema can extend to the tongue, floor of the mouth and larynx and compromise the airway, so it demands prompt assessment. Management involves antihistamines and corticosteroids, with epinephrine and emergency transfer if there is any airway involvement.
• C. A haematoma produces a firm, well-circumscribed, discoloured (blue-purple) swelling that develops within minutes to hours and is confined to the surgical site. Angioedema is diffuse and not discoloured.
• D. Cellulitis develops over one to three days with erythema, warmth, tenderness and often fever — it does not produce isolated, rapidly appearing lip swelling in the immediate post-operative period.

Note: Two mechanisms to keep separate. Histamine-mediated angioedema often has urticaria and itching and responds to antihistamines and epinephrine. Bradykinin-mediated angioedema — from ACE inhibitors or hereditary C1 esterase inhibitor deficiency — has no urticaria, does NOT respond to antihistamines or epinephrine, and needs icatibant or C1 inhibitor concentrate. Always ask about ACE inhibitors.