Angioedema in the ED
Swelling of face, lips, tongue, throat or larynx. Check the airway first, then find the mechanism.
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DermatologyEmergency
Angioedema Emergency Management
Angioedema Emergency Management: Angioedema in the ED → Check the airway first: senior help if threatened → Threatened airway: difficult-airway plan → A...
Pathway Overview
16 steps
Algorithm Steps
16 total
01Start 02Warning Check the airway first: senior help if threatened
Threatened airway: stridor, hoarse or muffled voice, drooling, trouble swallowing, breathing difficulty, or tongue or floor-of-mouth swelling.
- Threatened: call the most experienced airway operator (anaesthesia, ENT) now
- Give the cause-specific drug at the same time (next steps). If the cause is unclear, give adrenaline IM first
- Anaphylaxis possible: lay flat, or sit with legs outstretched if breathing is hard; do not stand or walk
03Warning Threatened airway: difficult-airway plan
Swelling can close the airway within minutes to hours. Plan for a difficult airway.
- Intubate early if swelling progresses. Give the cause-specific drug if it is at hand, but do not wait for it
- Awake fibreoptic intubation if time allows; avoid paralysis unless front-of-neck access is ready (double set-up)
- Mast-cell swelling with stridor: nebulised adrenaline 5 mL of 1 mg/mL (1:1000) while you prepare
04Action Airway not threatened now: watch closely
Swelling can progress over hours. Keep the patient in an area with airway equipment.
- Repeat airway checks: voice, swallowing, stridor, tongue and floor of mouth
- Nasendoscopy to look at the larynx if voice or swallowing changes
- Any new airway sign: go back to the threatened-airway plan
05Decision Mast-cell (allergic) or bradykinin mechanism?
Mast cell: urticaria, itch, flushing, wheeze, low BP or allergen exposure. Bradykinin: no urticaria or itch, with an ACE inhibitor or other trigger drug, or known or family history of HAE. If unsure, treat as mast cell first.
- Mast cell: onset in minutes; often urticaria and itch; responds to adrenaline
- Bradykinin: builds over hours; no urticaria; adrenaline, antihistamines and steroids do not help
- Bradykinin triggers: ACE inhibitor, ARB, sacubitril-valsartan, gliptin (DPP-4 inhibitor), thrombolysis, HAE
- If unsure: give adrenaline IM first; do not delay bradykinin-specific drugs
- Mast cell or unsure
06Action Mast cell or unsure: treat as allergic reaction or anaphylaxis
Anaphylaxis if tongue or throat swelling, hoarse voice, breathing difficulty, wheeze, or low BP. Do not let the patient stand or walk. Bradykinin cause likely (no urticaria, ACE inhibitor, HAE): adrenaline will not stop the swelling; use the bradykinin steps.
- Anaphylaxis (adult and child): adrenaline 1 mg/mL IM 0.01 mg/kg (max 0.5 mg) into outer thigh; repeat every 5 min if needed
- Give oxygen; IV access; monitor SpO2, BP and ECG
- Low BP: NaCl 0.9% 10-20 mL/kg IV bolus
- Pregnancy: give adrenaline without delay; left lateral position
- Lips, face or eyes only, no anaphylaxis signs: non-sedating oral antihistamine; watch for progression
- Antihistamines and steroids are adjuncts only, never instead of adrenaline; do not give IV promethazine
07Decision Improving after treatment?
Reassess airway, breathing and BP every 5 min.
- If Yes
08Action Improving: observe, then plan discharge
Observe at least 4 h after the last adrenaline dose. Overnight if severe or refractory reaction, severe asthma, lives alone or far from care, or late-evening presentation.
- Do not stand or walk until stable: at least 1 h after 1 adrenaline dose, 4 h after more than 1
- Before discharge after anaphylaxis: prescribe an adrenaline injector, train, give an ASCIA Action Plan
- Refer every anaphylaxis to a clinical immunology or allergy specialist
- Avoid the trigger
09Outcome Disposition: ICU, admit or discharge
ICU if intubated or high-risk airway. Admit if any airway involvement, progressing swelling, refractory anaphylaxis or unclear cause. Discharge only when the airway was never threatened, swelling is stable or going down, observation is complete, and follow-up is arranged.
- ICU: intubated or high-risk airway
- Admit: tongue, floor-of-mouth or laryngeal swelling; progressing swelling; refractory anaphylaxis; unclear cause
- Discharge: safety-net advice; return at once if swelling returns or breathing changes
If No10Action Not improving: adrenaline IM; after 2 doses, treat as refractory anaphylaxis
Progressing swelling or any anaphylaxis sign: adrenaline IM now. No improvement after 2 doses: call ED senior, ICU or anaesthetics and start an IV adrenaline infusion. Recheck for a bradykinin cause.
- Adrenaline infusion (adult and child): 1 mL of 1 mg/mL in 100 mL NaCl 0.9%; start at 0.5 mL/kg/h; titrate to response. Dedicated IV line, not on the BP-cuff arm; continuous monitoring
- Until the infusion runs: adrenaline IM every 5 min; NaCl 0.9% 10-20 mL/kg IV bolus for low BP
- On a beta-blocker and still refractory: glucagon IV (adult 1-2 mg every 5 min; child 40 microgram/kg, max 1 mg)
- No urticaria, takes an ACE inhibitor, or known HAE: follow the bradykinin steps below
- Path rejoins step 09Shared downstream outcome
- Bradykinin
11Action Bradykinin-mediated: adrenaline, antihistamines and steroids usually do not help
Protect the airway and stop the trigger. Give an HAE-specific drug early if HAE is known or likely. Angioedema after thrombolysis is different: see below.
- Stop the trigger drug now: ACE inhibitor, ARB, sacubitril-valsartan, gliptin
- Angioedema during or after thrombolysis (alteplase or tenecteplase): stop the infusion; mixed mechanism, so give an antihistamine and a steroid, and adrenaline IM if it progresses; tell the stroke team; watch the airway for 24 h
- If anaphylaxis cannot be excluded, adrenaline IM is still reasonable
12Decision Known or suspected hereditary angioedema (HAE)?
Known HAE, family history, recurrent swellings without urticaria, or recurrent abdominal pain attacks.
- If Yes
13Action HAE (known or suspected): treat now
Treat every attack that affects or may affect the airway. Early treatment works best.
- Ask for the patient's HAE action plan and own on-demand drug; use it
- Upper-airway attack: intubate early if swelling progresses; do not wait for the drug to arrive
- Adrenaline, antihistamines and steroids do not work in HAE
14Action HAE attack: C1-INH concentrate or icatibant
First line for HAE with C1-INH deficiency. Do not use tranexamic acid or danazol for an acute attack.
- C1-INH concentrate (Berinert IV) 20 IU/kg IV by slow injection (adult and child)
- OR icatibant 30 mg SC (adult); repeat after 6 h if needed; max 3 doses in 24 h
- Pregnancy or breastfeeding: C1-INH concentrate is first choice. Pregnancy: icatibant only if nothing else is available or C1-INH fails. Breastfeeding: after icatibant, do not breastfeed for 12 h
- Child 2-17 years: icatibant by weight: 12-25 kg 10 mg; 26-40 kg 15 mg; 41-50 kg 20 mg; 51-65 kg 25 mg; over 65 kg 30 mg (max 30 mg). One dose per attack (repeat not studied). Not under 2 years or 12 kg
- No HAE drug available: plasma (solvent-detergent plasma or FFP) for life-threatening attacks only; can worsen swelling
15Action Bradykinin angioedema: observe and plan follow-up
Untreated HAE attacks can last 2-5 days. Keep checking the airway until the swelling is clearly going down.
- ACE-inhibitor angioedema: stop it for good; record it as an adverse reaction; do not rechallenge
- Do not start sacubitril-valsartan after ACE-inhibitor or ARB angioedema, or in HAE (contraindicated)
- An ARB may be considered later with specialist advice; swelling can recur for weeks to months after stopping the ACE inhibitor
- Suspected HAE: send C4, C1-INH level and C1-INH function; refer to clinical immunology or allergy
- Known HAE: make sure the patient has on-demand drug for 2 attacks; specialist review of long-term prophylaxis
- Path rejoins step 09Shared downstream outcome
If No16Action Not HAE (ACE inhibitor, other drug or unknown): airway care; no proven drug
ACE inhibitor is the most common cause. It can start years after the drug was started. It usually resolves within 24-48 h of stopping the drug.
- Airway care and observation are the main treatment
- Icatibant or C1-INH: not proven for ACE-inhibitor angioedema (off-label); specialist advice for severe cases
- Adult: tranexamic acid 1 g IV may be considered (low-certainty evidence, off-label). Not if active thrombosis or high thrombosis risk
- Adrenaline, antihistamines and steroids usually do not help (angioedema after thrombolysis: see thrombolysis line above)
- Path rejoins step 15Shared downstream outcome
Guideline Source
International/Canadian hereditary angioedema guideline (2026); WAO/EAACI HAE guideline 2021 revision; ASCIA Acute Management of Anaphylaxis (2026)
Clinical Safety Information
Clinical Decision Support — Not a Substitute for Clinical Judgment
Individual patient factors may require deviation from these recommendations.
Known Limitations
- Mast-cell and bradykinin angioedema can look alike; if unsure, give adrenaline IM first
- No drug is proven for ACE-inhibitor angioedema; airway care comes first
- HAE with normal C1-INH, acquired C1-INH deficiency and long-term prophylaxis are not covered in detail
- HAE-specific drugs may not be stocked in every hospital; know where yours are kept
Contraindicated Populations
Children under 2 years or under 12 kg: icatibant not indicated (use C1-INH concentrate)Pregnancy: C1-INH concentrate is the HAE drug of choice; icatibant only if nothing else
Applicable Regions
AUNZUSEUUK
AU: Berinert IV (C1-INH concentrate) and icatibant are registered in Australia. Cinryze is registered but not marketed; ecallantide is not available. Anaphylaxis care follows ASCIA 2026.
US: Ecallantide 30 mg SC is also licensed in the US for HAE (age 12 years and over); give only where anaphylaxis can be treated.
Version 2Next review: 2027-09-30
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Frequently Asked Questions
What is the Angioedema Emergency Management?
The Angioedema Emergency Management is a emergency clinical algorithm for Dermatology. It provides a structured decision tree to guide clinical decision-making, based on International/Canadian hereditary angioedema guideline (2026); WAO/EAACI HAE guideline 2021 revision; ASCIA Acute Management of Anaphylaxis (2026).
What guideline is the Angioedema Emergency Management based on?
This algorithm is based on International/Canadian hereditary angioedema guideline (2026); WAO/EAACI HAE guideline 2021 revision; ASCIA Acute Management of Anaphylaxis (2026) (DOI: 10.1186/s13223-025-00999-8).
What are the limitations of the Angioedema Emergency Management?
Known limitations include: Mast-cell and bradykinin angioedema can look alike; if unsure, give adrenaline IM first; No drug is proven for ACE-inhibitor angioedema; airway care comes first; HAE with normal C1-INH, acquired C1-INH deficiency and long-term prophylaxis are not covered in detail; HAE-specific drugs may not be stocked in every hospital; know where yours are kept. Individual patient factors may require deviation from these recommendations.
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