What is the immediate treatment for angioedema in a 6-year-old?

Immediate Treatment for Angioedema in a 6-Year-Old

The immediate priority is assessing for life-threatening airway involvement, then determining whether the angioedema is histamine-mediated (allergic) or bradykinin-mediated (hereditary), as treatments differ completely and using the wrong approach wastes critical time. 1

Immediate Airway Assessment and Stabilization

• Check immediately for oropharyngeal or laryngeal edema, respiratory distress, voice changes, difficulty swallowing, or signs of shock as these indicate life-threatening airway involvement. 1
• Monitor the child in a facility capable of performing intubation or tracheostomy if any oropharyngeal or laryngeal involvement is present. 1, 2
• Consider elective intubation if signs of impending airway closure develop, such as voice changes, inability to swallow, or breathing difficulty. 1, 2
• Administer high-flow oxygen via face mask for severe laryngeal edema. 1
• Avoid direct visualization of the airway unless absolutely necessary, as trauma can worsen angioedema. 1, 2

Determine Angioedema Type

This step is critical because histamine-mediated and bradykinin-mediated angioedema require completely different treatments:

• Histamine-mediated (allergic) angioedema presents with urticaria (hives), pruritus (itching), and responds to antihistamines and epinephrine. 1, 3
• Bradykinin-mediated angioedema (hereditary angioedema/HAE) has no urticaria, no pruritus, and does NOT respond to standard allergy treatments. 1, 3

Treatment Based on Type

For Histamine-Mediated (Allergic) Angioedema:

• Administer intramuscular epinephrine immediately for significant symptoms or any airway involvement, using weight-based dosing (0.01 mg/kg, maximum 0.3-0.5 mg). 4, 1, 2
• Give IV diphenhydramine (1 mg/kg, maximum 50 mg) and IV methylprednisolone (1-2 mg/kg, maximum 125 mg) as adjunctive therapy. 1, 3, 2
• Add H2 blockers such as ranitidine or famotidine. 3, 2
• If no significant relief after the first epinephrine dose, give a second dose. 4

For Bradykinin-Mediated (Hereditary) Angioedema:

• Administer C1 inhibitor replacement therapy (plasma-derived C1-INH, 1000-2000 U IV) as the preferred treatment for hereditary angioedema with laryngeal involvement. 1, 3, 2
• Alternative specific therapies include icatibant (bradykinin B2 receptor antagonist, 30 mg subcutaneously) or ecallantide (plasma kallikrein inhibitor). 4, 3
• Standard angioedema treatments (epinephrine, corticosteroids, antihistamines) are NOT effective for hereditary angioedema and waste critical time. 4, 1, 3, 2
• Fresh frozen plasma (10-15 mL/kg) may be considered if specific targeted therapies are unavailable, though it carries risk of viral transmission and can occasionally worsen symptoms. 4, 3, 2

Supportive Care

• Provide aggressive IV hydration for abdominal attacks, as third-space fluid sequestration is common. 4, 1, 3
• Administer antiemetics for nausea and vomiting. 4, 1, 3
• Give appropriate analgesia for pain control, but avoid creating narcotic dependence in patients with frequent attacks. 4, 1

Laboratory Workup (When Stable)

• Order serum C4 level as the screening test for hereditary or acquired C1 inhibitor deficiency in angioedema without urticaria. 1
• If C4 is low, confirm with quantitative and functional C1 inhibitor assays. 1

Observation and Disposition

• Observe until symptoms have significantly improved before discharge. 1, 3
• Extended observation is mandatory for laryngeal attacks, as historical mortality rates approach 30% without treatment. 1, 3
• Never discharge patients with oropharyngeal or laryngeal involvement without adequate observation. 1, 3, 2

Critical Pitfalls to Avoid

• Never delay epinephrine in histamine-mediated angioedema with airway involvement. 1, 2
• Never use standard allergy treatments for confirmed or suspected hereditary angioedema, as they are ineffective and waste critical time. 4, 1, 3, 2
• Never discharge patients with oropharyngeal or laryngeal involvement without adequate observation. 1, 3
• Never prescribe ACE inhibitors to patients with any form of angioedema, especially hereditary angioedema. 1

Long-Term Considerations for Hereditary Angioedema

• Tranexamic acid (30-50 mg/kg/day) is the preferred long-term prophylaxis in children where first-line C1-INH replacement is unavailable. 1, 3, 2
• Attenuated androgens may be considered but carry high side effect burden in children. 1, 3
• Administer C1-INH concentrate for short-term prophylaxis before dental or surgical procedures. 1, 3