Initial Management of Angioedema
Immediate Airway Assessment
The first and most critical step is to immediately assess for airway compromise, as this determines whether the patient requires emergent intervention or can proceed with medical management. 1
- Evaluate for signs of oropharyngeal or laryngeal involvement including voice changes, difficulty swallowing, stridor, or respiratory distress 2, 1
- Patients with any laryngeal or oropharyngeal edema must be monitored in a facility capable of performing emergency intubation or tracheostomy 1, 3
- Consider elective intubation before complete airway obstruction occurs if the patient exhibits change in voice, loss of ability to swallow, or difficulty breathing 2, 1
- Awake fiberoptic intubation is optimal; avoid direct visualization unless absolutely necessary as trauma can worsen angioedema 2, 1
- Have backup tracheostomy equipment immediately available 1
Determine Angioedema Type
Rapidly differentiate between histamine-mediated and bradykinin-mediated angioedema as treatments differ completely and are not interchangeable. 1, 4
Clinical Features Distinguishing the Types:
- Histamine-mediated angioedema: Accompanied by urticaria (hives), pruritus, responds to antihistamines and epinephrine 4, 5
- Bradykinin-mediated angioedema: No urticaria, no pruritus, does NOT respond to standard allergy treatments 4, 6
- Obtain medication history immediately—ACE inhibitors are a common cause of bradykinin-mediated angioedema 2
- Check for family history of recurrent angioedema suggesting hereditary angioedema (HAE) 2
Treatment Based on Type
For Histamine-Mediated Angioedema:
- Administer epinephrine (0.1%) 0.3 mL subcutaneously or 0.5 mL by nebulizer immediately for significant symptoms or any airway involvement 2, 1, 4
- Give IV diphenhydramine 50 mg 2, 1, 4
- Give IV methylprednisolone 125 mg 2, 1, 4
- Add H2 blocker: ranitidine 50 mg IV or famotidine 20 mg IV 2, 1, 4
For Bradykinin-Mediated Angioedema (HAE or ACE Inhibitor-Induced):
- Immediately discontinue ACE inhibitor permanently if this is the suspected cause 2, 1, 4
- Administer icatibant (selective bradykinin B2 receptor antagonist) 30 mg subcutaneously in the abdominal area 2, 1, 7
- Additional doses of icatibant may be given at 6-hour intervals if response is inadequate, up to 3 doses in 24 hours 7
- Alternatively, administer plasma-derived C1 inhibitor concentrate 1000-2000 U (or 20 IU/kg) intravenously 2, 1, 4
- If specific targeted therapies are unavailable, consider fresh frozen plasma 10-15 mL/kg 1, 4
- Standard allergy treatments (antihistamines, corticosteroids, epinephrine) are completely ineffective for bradykinin-mediated angioedema and waste critical time 1, 4, 8
Supportive Care
- Maintain airway patency as the absolute priority 2, 1
- Provide high-flow oxygen if respiratory compromise is present 3
- For abdominal attacks, provide aggressive IV hydration, antiemetics, and analgesics 1, 4
- Monitor vital signs continuously 2
- Hold all ACE inhibitors 2, 1
Critical Pitfalls to Avoid
- Never delay epinephrine administration in histamine-mediated angioedema with airway involvement 1, 3
- Never use standard allergy treatments for confirmed or suspected bradykinin-mediated angioedema—they are ineffective and delay appropriate therapy 1, 4, 8
- Never discharge patients with oropharyngeal or laryngeal involvement without adequate observation, as laryngeal attacks carry historical mortality rates approaching 30% 1, 4
- Do not attempt direct airway visualization unless absolutely necessary, as this can worsen edema 1, 3