Angioedema Presenting to ED
Swelling of face, lips, tongue, uvula, or larynx
All Pathways
DermatologyEmergency
Angioedema Emergency Management
Angioedema Emergency Management: Angioedema Presenting to ED → Immediate Airway Assessment → Airway Compromised → Differentiate Mechanism → Histamine-Me...
Pathway Overview
15 steps
Algorithm Steps
15 total
01Start 02Warning Immediate Airway Assessment
Is airway compromised?
- Stridor, dyspnea, drooling, voice changes
- Prepare for difficult airway
- Have cricothyrotomy equipment ready
- Avoid paralysis without backup plan
03Warning Airway Compromised
Urgent airway intervention needed
- Call anesthesia/ENT for backup
- Awake fiberoptic intubation preferred
- Avoid paralysis if possible
- Double setup: intubation + surgical airway ready
- Consider nasopharyngeal scope to assess
- Heliox may temporize
04Decision Differentiate Mechanism
Histamine-mediated vs Bradykinin-mediated
- HISTAMINE: Fast onset (min-hrs), urticaria/pruritus, responds to epinephrine
- BRADYKININ: Slow onset (24-36h), NO urticaria, does NOT respond to epinephrine
- Clues for bradykinin: ACE-I use, HAE history, family history, recurrent episodes without urticaria
05Action Histamine-Mediated (Allergic)
Treat as anaphylaxis
- EPINEPHRINE IM: 0.3-0.5 mg (0.01 mg/kg in children)
- Repeat q5-15min if needed
- H1 blocker: Diphenhydramine 25-50mg IV
- H2 blocker: Famotidine 20mg IV
- Corticosteroids: Methylprednisolone 125mg IV
- IV fluids for hypotension
06Decision Response to Treatment?
Assess within 15-30 minutes
07Outcome Improving
Continue monitoring, discharge with EpiPen
- Observe 4-6 hours minimum
- Prescribe EpiPen
- Allergy referral
- Avoid trigger
08Action Ongoing Monitoring
All patients require observation
- Serial airway exams
- Bradykinin attacks peak at 24h, resolve 48-72h
- HAE: Consider prophylaxis (C1-INH, lanadelumab)
- ACE-I: Document allergy, never rechallenge
- Order C4, C1-INH level if HAE suspected
09Outcome Disposition
Based on severity and response
- Admit: Any airway involvement, severe attacks, uncertain diagnosis
- ICU: Intubated, high-risk airway
- Discharge: Mild, resolved, with safety net and follow-up
10Action Not Responding
Reconsider diagnosis
- May be bradykinin-mediated
- Try bradykinin-specific therapy
- Reassess for impending airway compromise
11Action Bradykinin-Specific Treatments
Order based on availability and indication
- 1ST LINE - Tranexamic acid: 1g IV, can repeat (widely available)
- C1-INH CONCENTRATE (Berinert): 20 units/kg IV (first-line for HAE)
- Icatibant: 30mg SC (HAE; less effective for ACE-I induced)
- Ecallantide: 30mg SC (HAE only; 3% anaphylaxis risk)
- FFP: 2 units (if others unavailable; theoretical worsening risk)
- Path rejoins step 08Shared downstream outcome
12Action Bradykinin-Mediated
Does NOT respond to epinephrine/antihistamines
- ACE inhibitor: STOP drug permanently
- Hereditary: C1-INH deficiency
- Acquired: Associated with lymphoproliferative disorders
- Duration typically 48-72h if untreated
13Action ACE Inhibitor-Induced
Most common cause of bradykinin angioedema
- STOP ACE inhibitor permanently
- Can occur after years of use
- Switch to ARB with caution (some cross-reactivity)
- May recur for weeks after stopping
- Path rejoins step 11Shared downstream outcome
14Action Hereditary Angioedema (HAE)
C1-INH deficiency - genetic disorder
- Family history, recurrent attacks
- Abdominal attacks common
- Low C4 level (screening test)
- Low C1-INH level or function confirms
- Path rejoins step 11Shared downstream outcome
15Action Airway Currently Stable
Proceed with evaluation but remain vigilant
- Can worsen rapidly over hours
- Close monitoring essential
- Serial airway exams
- Path rejoins step 04Shared downstream outcome
Guideline Source
IBCC Angioedema Chapter + AAEM Guidelines
Clinical Safety Information
Clinical Decision Support — Not a Substitute for Clinical Judgment
Individual patient factors may require deviation from these recommendations.
Known Limitations
- Differentiation between histamine and bradykinin can be challenging
- Specific HAE therapies may not be readily available
- Airway management requires expertise for potential difficult airway
- Cost of HAE-specific treatments is significant
- Does not address pediatric-specific dosing
Applicable Regions
USEU
Version 1Next review: 2027-01-11
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Related Resources
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 IBCC Angioedema Chapter + AAEM Guidelines.
What guideline is the Angioedema Emergency Management based on?
This algorithm is based on IBCC Angioedema Chapter + AAEM Guidelines.
What are the limitations of the Angioedema Emergency Management?
Known limitations include: Differentiation between histamine and bradykinin can be challenging; Specific HAE therapies may not be readily available; Airway management requires expertise for potential difficult airway; Cost of HAE-specific treatments is significant; Does not address pediatric-specific dosing. Individual patient factors may require deviation from these recommendations.
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