Synopsis
Separate mast-cell-mediated angioedema from bradykinin-mediated and other swelling, secure the airway early, and investigate recurrent episodes without misusing allergy tests.
- Angioedema is deeper swelling of skin or mucosa; eyelids and lips are common, but tongue, larynx and bowel involvement determine danger.
- Wheals, itch, rapid onset and an obvious allergen support mast-cell disease; absence of wheals, slower onset and abdominal attacks support bradykinin disease.
- ACE-inhibitor angioedema may occur after years of treatment; stop the ACE inhibitor permanently and document it clearly.
- For recurrent angioedema without wheals, measure C4 plus C1-inhibitor antigenic level and function, ideally with specialist interpretation and repeat confirmation.
- Normal oxygen saturation does not exclude a threatened upper airway, and blood sampling must never delay airway management.
- Antihistamines and corticosteroids are not effective disease-specific treatments for bradykinin angioedema; use the specialist emergency plan.
- Angioedema with and without urticaria must be assessed by lesion duration, onset, distribution, symptoms, mucosal findings, systemic physiology and the full medicine timeline rather than by colour alone.
- For Angioedema with and without urticaria, document the working diagnosis, excluded emergencies, uncertain culprit or trigger, treatment response and the exact safety-net given.
Key red flags
Voice change, stridor, drooling, dysphagia, tongue swelling, respiratory distress, hypotension, rapid progression or previous difficult airway requires immediate hospital care.
Tongue, floor-of-mouth or laryngeal swelling, altered voice, drooling or stridor requires immediate airway expertise and repeated examination.
Investigation priorities
Detect progression before obstruction becomes physiologically obvious.
Management branches
Swelling affects tongue or airway, progresses rapidly, or accompanies breathing or circulation compromise.
- Call anaesthetic and resuscitation support, position according to physiology, provide high-flow oxygen and monitor continuously while planning a difficult airway.
- Give intramuscular adrenaline promptly when anaphylaxis is suspected and repeat after five minutes if ABC compromise persists.
- Use disease-specific hereditary-angioedema rescue treatment immediately when a confirmed patient’s plan indicates it, without allowing classification uncertainty to delay airway control.
Key medicines
Intramuscular adrenaline 1 mg/mL solutionFor adult anaphylaxis give 500 micrograms intramuscularly, equal to 0.5 mL of 1 mg/mL solution, into the anterolateral thigh; repeat after five minutes if ABC problems persist.Use the intramuscular route initially, monitor continuously, avoid inadvertent intravenous bolus, and seek expert support for refractory anaphylaxis or a threatened difficult airway.
Cetirizine 10 mg tabletsAdults and adolescents aged 12 years and over take 10 mg orally once daily, adjusted for renal impairment according to product guidance.Somnolence, alcohol, driving, renal function, pregnancy and breastfeeding need review; a non-response should trigger mediator reassessment rather than automatic repeated dosing.