Type II Hereditary Angioedema—Presenting as Food Allergy

Excerpt

Hereditary angioedema (HAE) is caused by a genetic defect of C1 inhibitor (C1INH), a control protein of the classical complement pathway. In the majority of cases the disease is inherited in an autosomal dominant manner, however, up to 25% of patients may present with a de novo mutation. It is well established that approximately 85% of patients have low or undetectable levels of C1INH (type I HAE), however, 15% of patients can present with normal or increased levels of dysfunctional C1INH (type II HAE). The clinical manifestations of both types of HAE are very similar and are due to uncontrolled activation of the complement pathway. The characteristic clinical presentation is recurrent episodes of angioedema affecting different parts of the body including the face, hands, feet, upper airways, and abdomen. The disease has a prevalence of 1 in 50,000 and can often be misdiagnosed. While most children will have had at least one episode before the teenage years, many are not diagnosed until the second or third decade [1]. …