What is the treatment for angioedema?

Treatment of Angioedema

The treatment of angioedema depends on its classification as either histamine-mediated or bradykinin-mediated, with first-line treatments for hereditary angioedema (HAE) being plasma-derived C1 inhibitor (pdC1INH) at 20 IU/kg IV or icatibant 30 mg subcutaneously. 1

Classification of Angioedema

Angioedema can be classified into two main categories that determine treatment approach:

1. Histamine-mediated angioedema

   • Often associated with allergen exposure
   • Usually presents with urticaria (hives)
   • Responds to standard treatments (epinephrine, antihistamines, corticosteroids)

2. Bradykinin-mediated angioedema

   • Includes hereditary angioedema (HAE), acquired C1 inhibitor deficiency, and ACE inhibitor-associated angioedema
   • Does not present with urticaria
   • Does NOT respond to standard allergic reaction treatments 1, 2

Treatment Algorithm

For Histamine-Mediated Angioedema:

• Epinephrine (intramuscular)
• Antihistamines
• Corticosteroids

For Bradykinin-Mediated Angioedema (including HAE):

1. First-line treatments (in order of preference):

   • Plasma-derived C1 esterase inhibitor (pdC1INH): 20 IU/kg IV 1
   • Icatibant: 30 mg subcutaneously in abdominal area (may repeat at 6-hour intervals, maximum 3 injections in 24 hours) 1, 3
   • Ecallantide (where available) 4

2. When first-line treatments are unavailable:

   • Fresh frozen plasma (FFP): 10-15 ml/kg body weight 1
     • Response is slower than with specific HAE medications
     • First improvement seen in 90 minutes to 12 hours
     • Complete resolution in 2-18 hours (median 4 hours)
     • Requires close observation for at least 4-6 hours

3. For laryngeal/upper airway angioedema:

   • Consider early intubation or tracheotomy if airway compromise is present or imminent 4
   • Endotracheal intubation is usually preferred to tracheostomy for securing a temporary airway 5

Special Considerations

For Pregnant Patients:

• pdC1INH is the preferred treatment
• FFP can be used if pdC1INH is unavailable 1

Long-term Prophylaxis Options:

• Plasma-derived C1INH (IV or subcutaneous formulations)
• Danazol: 100 mg alternate days to 600 mg daily (contraindicated in pregnancy, breast cancer, childhood, liver disease)
• Tranexamic acid: 30-50 mg/kg/day in 2-3 divided doses (maximum 3 g/day) 1

Important Caveats

1. Standard angioedema treatments (epinephrine, corticosteroids, antihistamines) are NOT effective for HAE attacks 1

2. Early treatment is crucial for pharyngeal attacks to prevent progression to complete airway obstruction 1

3. ACE inhibitors can trigger or worsen angioedema and should be discontinued immediately if suspected as the cause 6

4. Patients with HAE should have:

   • An established emergency plan for responding to laryngeal attacks
   • Immediate access to on-demand HAE-specific medications
   • Medical alert identification 1

5. Estrogen-containing contraceptives should be avoided in patients with HAE 1

6. For drug-induced angioedema, the most important action is to discontinue the causative medication 6

By correctly identifying the type of angioedema and following appropriate treatment protocols, clinicians can effectively manage this potentially life-threatening condition.