Hereditary Angioedema - Diagnosis

Diagnosis

Recognizing HAE is often difficult due to the wide variability in disease expression. The course of the disease is diverse and unpredictable, even within a single patient over their lifetime. This disease may be similar in its presentation to other forms of angioedema resulting from allergies or other medical conditions, but it is significantly different in cause and treatment. When hereditary angioedema is misdiagnosed as an allergy it is most commonly treated with steroids and epinephrine, drugs that are usually ineffective in treating a hereditary angioedema episode. Other misdiagnoses have resulted in unnecessary exploratory surgery for patients with abdominal swelling and other hereditary angioedema patients report that their abdominal pain was wrongly diagnosed as psychosomatic.

HAE accounts for only a small fraction of all cases of angioedema. To avoid potentially fatal consequences such as upper airway obstruction and unnecessary abdominal surgery, the importance of a correct diagnosis cannot be over-emphasized. View Diagnosis Algorithm Flowchart Diagnosis Algorithm Flowchart.

Consider Hereditary Angioedema (HAE) if a patient presents with:

• Recurrent angioedema (without urticaria)
• Recurrent episodes of abdominal pain and vomiting
• Laryngeal edema
• Positive family history of angioedema

A blood test, ideally taken during an episode, can be used to diagnose the condition. Measure: serum complement factor 4 (C4), C1 inhibitor (C1-INH) antigenic protein, C1 inhibitor (C1-INH) functional level if available.

Analysis of complement C1 inhibitor levels may play a role in diagnosis. C4 and C2 are complementary components.