What is the treatment for angioneurotic edema?

Treatment of Angioedema

Immediate Airway Assessment and Management

The most critical first step is immediate assessment for airway compromise, as laryngeal involvement can be fatal—historically carrying approximately 30% mortality without treatment. 1, 2

• Patients with oropharyngeal or laryngeal involvement must be monitored in a facility capable of performing intubation or tracheostomy 1, 2, 3
• Consider elective intubation if signs of impending airway closure develop: voice changes, inability to swallow, or breathing difficulty 2, 3
• Avoid direct airway visualization unless absolutely necessary, as trauma can worsen angioedema 3, 4
• Have backup tracheostomy equipment immediately available 3

Differentiate Angioedema Type

Treatment depends entirely on whether the angioedema is histamine-mediated (allergic) or bradykinin-mediated—standard allergy treatments are completely ineffective for bradykinin-mediated forms. 1, 2

Clinical Clues:

• Histamine-mediated: Accompanied by urticaria, pruritus, rapid onset (minutes), responds to antihistamines/epinephrine 2, 3, 5
• Bradykinin-mediated: No urticaria, no pruritus, slower onset (hours), resistant to standard allergy treatments 1, 5
• ACE inhibitor use strongly suggests bradykinin-mediated angioedema 1, 2, 6
• Family history of similar attacks suggests hereditary angioedema (HAE) 1, 2

Treatment Based on Type

Histamine-Mediated (Allergic) Angioedema

Administer epinephrine immediately for significant symptoms or any airway involvement—delaying epinephrine is a critical error. 2, 3

• Epinephrine 0.3 mL (0.1%) subcutaneously or 0.5 mL by nebulizer 2, 3
• IV diphenhydramine 50 mg 2, 3
• IV methylprednisolone 125 mg 2, 3
• Add H2 blockers: ranitidine 50 mg IV or famotidine 20 mg IV 2, 3

Bradykinin-Mediated Angioedema

Hereditary Angioedema (HAE)

Three FDA-approved medications are available for acute HAE attacks: plasma-derived C1 inhibitor concentrate, icatibant, and ecallantide—all are safe and effective, with early treatment being most beneficial. 1

Acute Attack Treatment:

• Plasma-derived C1 inhibitor: 1000-2000 U (or 20 IU/kg) intravenously 2, 3, 7
  • Median time to symptom relief for laryngeal attacks: 0.25 hours 7
  • Median time to complete resolution: 8.4 hours 7
• Icatibant: 30 mg subcutaneously 1, 2, 3
  • Earlier treatment (<1 hour from onset) reduces attack duration from 16.8 to 6.1 hours 1
  • Self-administration enables faster treatment than waiting for healthcare provider 1
• Ecallantide: plasma kallikrein inhibitor 1

Critical Point: Standard treatments (epinephrine, corticosteroids, antihistamines) are NOT effective for HAE and waste critical time 1, 2

If specific therapies unavailable:

• Fresh frozen plasma 10-15 mL/kg can be used, though it may occasionally worsen symptoms and carries viral transmission risk 1, 2

Short-Term Prophylaxis (before procedures):

• Plasma-derived C1 inhibitor 1000-2000 U intravenously 2, 4
• Alternative: attenuated androgens (danazol 2.5-10 mg/kg) or tranexamic acid 2

Long-Term Prophylaxis (for frequent attacks):

• Androgens (danazol 100 mg on alternate days) with regular monitoring for hepatotoxicity 2
• Tranexamic acid 30-50 mg/kg/day 2
• Plasma-derived C1 inhibitor for regular prophylaxis 1

ACE Inhibitor-Induced Angioedema

Immediately and permanently discontinue the ACE inhibitor—this is non-negotiable. 2, 3

• Consider icatibant 30 mg subcutaneously 2, 3
• Standard allergy treatments are ineffective 5
• Never restart ACE inhibitors; consider alternative antihypertensives 2, 4

Supportive Care

For abdominal attacks, aggressive management of fluid sequestration and pain is essential, as third-space fluid losses can cause significant hypotension. 1

• Aggressive IV hydration for abdominal attacks 1, 3
• Narcotic analgesia for severe pain (but avoid chronic potent narcotics like fentanyl patches or oxycodone due to addiction risk) 1, 3
• Antiemetics for nausea and vomiting 1, 3

Special Populations

Pregnant Patients

• C1 inhibitor concentrate is the only recommended treatment for HAE during pregnancy 2, 7

Children

• Tranexamic acid is preferred for long-term prophylaxis where C1 inhibitor is unavailable 2, 4
• Fresh frozen plasma for acute treatment when first-line agents unavailable 2, 4
• Attenuated androgens carry high side effect burden in children 2, 4

Critical Pitfalls to Avoid

• Never delay epinephrine in histamine-mediated angioedema with airway involvement 3, 4
• Never use standard allergy treatments for bradykinin-mediated angioedema—they are completely ineffective 1, 2
• Never discharge patients with oropharyngeal or laryngeal involvement without adequate observation 1, 2, 4
• Never perform unnecessary surgical interventions for abdominal attacks—many HAE patients have undergone inappropriate laparotomies 1, 8
• Never prescribe ACE inhibitors to patients with any history of angioedema 4

Early Treatment Emphasis

Administering on-demand treatment as early as possible dramatically improves outcomes—patients should be trained in self-administration when appropriate. 1

• Treatment within 1 hour of onset reduces attack duration by 63% compared to later treatment 1
• All patients with HAE should have an established emergency plan and access to effective on-demand medication 1
• Self-administration enables treatment initiation within 2-3 hours versus 6-8 hours with healthcare provider administration 1