Angioedema
A streamlined, differential-led presentation for rapid clinical review.
Twenty-second review
- Angioedema is swelling of deeper tissues from histamine or bradykinin pathways and can rapidly compromise tongue, pharynx, or larynx.
- Voice change, tongue or floor-of-mouth swelling, stridor, drooling, dyspnea, shock, or rapid progression is an airway emergency.
- Keep dental or deep-neck infection in the differential; overlapping or concurrent illness remains possible.
- For angioedema, trends and combinations of findings are more informative than one isolated vital sign.
Compare the clinical patterns
The repeated material is grouped inside each possibility. Open only the condition you need.
Bradykinin-mediatedTime-sensitive high-risk possibility
HPI
Clarify onset and progression; tongue, lip or throat involvement; voice, swallowing and breathing.
Signs & symptoms
ACE inhibitor use, absent hives, family history, or worsening tongue swelling.
Focused exam
Inspect the airway, skin, face, and exposed areas; auscultate lungs and assess perfusion; Reassess frequently because swelling and shock may progress.
Brief pathophysiology
Bradykinin-mediated may cause angioedema through a time-sensitive process capable of rapid physiological deterioration.
What the trend may show
Airway sounds, voice, work of breathing, and trajectory are more important than a single normal SpO₂. Deteriorating effort or rate may indicate fatigue, not improvement.
Respiratory rate (breaths/min)
Usually rises firstTachypnea and increased effort commonly precede late respiratory failure.
Oxygen saturation (SpO₂)
May fall lateOxygen saturation can remain normal until obstruction becomes severe.
Heart rate (bpm)
Often risesTachycardia may reflect hypoxia, distress, or compensatory response.
Blood pressure (mmHg)
Usually preservedHypotension suggests advanced hypoxia, anaphylaxis, or another shock state.
Front-load in the triage report
- Bradykinin-mediated: ACE inhibitor use, absent hives, family history, or worsening tongue swelling.
- Onset and progression?
- Tongue, lip or throat involvement?
Progressive airway edemaTime-sensitive high-risk possibility
HPI
Clarify tongue, lip or throat involvement; voice, swallowing and breathing; medication trigger, especially ace inhibitor.
Signs & symptoms
ACE inhibitor use, absent hives, family history, or worsening tongue swelling.
Focused exam
Reassess frequently because swelling and shock may progress; Inspect lips, tongue, oral cavity, face, skin, and airway while assessing medication triggers, allergy symptoms, family history, and abdominal pain.
Brief pathophysiology
Progressive airway edema may cause angioedema through a time-sensitive process capable of rapid physiological deterioration.
What the trend may show
Airway sounds, voice, work of breathing, and trajectory are more important than a single normal SpO₂. Deteriorating effort or rate may indicate fatigue, not improvement.
Respiratory rate (breaths/min)
Usually rises firstTachypnea and increased effort commonly precede late respiratory failure.
Oxygen saturation (SpO₂)
May fall lateOxygen saturation can remain normal until obstruction becomes severe.
Heart rate (bpm)
Often risesTachycardia may reflect hypoxia, distress, or compensatory response.
Blood pressure (mmHg)
Usually preservedHypotension suggests advanced hypoxia, anaphylaxis, or another shock state.
Front-load in the triage report
- Progressive airway edema: ACE inhibitor use, absent hives, family history, or worsening tongue swelling.
- Tongue, lip or throat involvement?
- Voice, swallowing and breathing?
Histamine-mediated angioedemaCommon presentation pattern
HPI
Clarify onset and progression; tongue, lip or throat involvement; voice, swallowing and breathing.
Signs & symptoms
Urticaria, itch, exposure, and rapid onset may accompany allergy.
Focused exam
Inspect the airway, skin, face, and exposed areas; auscultate lungs and assess perfusion; Reassess frequently because swelling and shock may progress.
Brief pathophysiology
Histamine-mediated angioedema may explain the presenting symptoms through a common clinical mechanism, while serial assessment checks for complications or an alternate cause.
What the trend may show
Airway sounds, voice, work of breathing, and trajectory are more important than a single normal SpO₂. Deteriorating effort or rate may indicate fatigue, not improvement.
Respiratory rate (breaths/min)
Usually rises firstTachypnea and increased effort commonly precede late respiratory failure.
Oxygen saturation (SpO₂)
May fall lateOxygen saturation can remain normal until obstruction becomes severe.
Heart rate (bpm)
Often risesTachycardia may reflect hypoxia, distress, or compensatory response.
Blood pressure (mmHg)
Usually preservedHypotension suggests advanced hypoxia, anaphylaxis, or another shock state.
Front-load in the triage report
- Urticaria, itch, exposure, and rapid onset may accompany allergy.
- Onset and progression?
- Tongue, lip or throat involvement?
DentalImportant alternative presentation
HPI
Clarify onset and progression; tongue, lip or throat involvement; voice, swallowing and breathing.
Signs & symptoms
Focal pain, fever, asymmetry, or toxic appearance suggests infection.
Focused exam
Inspect the airway, skin, face, and exposed areas; auscultate lungs and assess perfusion; Reassess frequently because swelling and shock may progress.
Brief pathophysiology
Dental can resemble angioedema through overlapping symptoms or referred physiology despite a different primary mechanism.
What the trend may show
Airway sounds, voice, work of breathing, and trajectory are more important than a single normal SpO₂. Deteriorating effort or rate may indicate fatigue, not improvement.
Respiratory rate (breaths/min)
Usually rises firstTachypnea and increased effort commonly precede late respiratory failure.
Oxygen saturation (SpO₂)
May fall lateOxygen saturation can remain normal until obstruction becomes severe.
Heart rate (bpm)
Often risesTachycardia may reflect hypoxia, distress, or compensatory response.
Blood pressure (mmHg)
Usually preservedHypotension suggests advanced hypoxia, anaphylaxis, or another shock state.
Front-load in the triage report
- Focal pain, fever, asymmetry, or toxic appearance suggests infection.
- Onset and progression?
- Tongue, lip or throat involvement?
Deep-neck infectionImportant alternative presentation
HPI
Clarify tongue, lip or throat involvement; voice, swallowing and breathing; medication trigger, especially ace inhibitor.
Signs & symptoms
Focal pain, fever, asymmetry, or toxic appearance suggests infection.
Focused exam
Reassess frequently because swelling and shock may progress; Inspect lips, tongue, oral cavity, face, skin, and airway while assessing medication triggers, allergy symptoms, family history, and abdominal pain.
Brief pathophysiology
Deep-neck infection can resemble angioedema through overlapping symptoms or referred physiology despite a different primary mechanism.
What the trend may show
Airway sounds, voice, work of breathing, and trajectory are more important than a single normal SpO₂. Deteriorating effort or rate may indicate fatigue, not improvement.
Respiratory rate (breaths/min)
Usually rises firstTachypnea and increased effort commonly precede late respiratory failure.
Oxygen saturation (SpO₂)
May fall lateOxygen saturation can remain normal until obstruction becomes severe.
Heart rate (bpm)
Often risesTachycardia may reflect hypoxia, distress, or compensatory response.
Blood pressure (mmHg)
Usually preservedHypotension suggests advanced hypoxia, anaphylaxis, or another shock state.
Front-load in the triage report
- Focal pain, fever, asymmetry, or toxic appearance suggests infection.
- Tongue, lip or throat involvement?
- Voice, swallowing and breathing?
Findings that should escalate concern
- Tongue or laryngeal swelling
- Voice change
- Stridor
- Rapid progression
- Voice change, tongue or floor-of-mouth swelling, stridor, drooling, dyspnea, shock, or rapid progression is an airway emergency.
- Bradykinin-mediated or progressive airway edema: ACE inhibitor use, absent hives, family history, or worsening tongue swelling.
Medication recognition
Continue the clinical pathway
Clinical and academic sources
Curated clinical guidance and peer-reviewed evidence supporting this presentation. Current BCEHS guidance, medical direction, and local policy remain authoritative for practice.
BCEHS Handbook — specific CPGs
Supporting clinical and academic evidence
- CEDIS Presenting Complaint List updateCanadian Association of Emergency Physicians
Presenting-complaint terminology and categorization context. It does not establish a prehospital “top 100” ranking.
- World Allergy Organization anaphylaxis guidance 2020World Allergy Organization
Peer-reviewed international guidance on recognizing and managing anaphylaxis.
- Hereditary AngioedemaEmergency Medicine Clinics of North America · 2022
Airway-focused assessment and differentiation of histamine- and bradykinin-mediated angioedema.