In patients with the rare autosomal dominant genetic disorder hereditary angioedema (HAE), the disease can be life-threatening if left untreated, leading to such complications as difficulty breathing, airway obstruction, and severe abdominal pain.

The authors described the case of a 22-year-old woman who presented to the emergency department (ED) with complaints of difficulty swallowing and a persistent sore throat. Findings from the case study were published recently in the journal Cureus.

Individuals with HAE have a deficit (HAE type I) or dysfunction (HAE type II) in the C1 esterase inhibitor (C1-INH). HAE is caused by a mutation in the SERPING1 gene, which encodes the C1-INH protein, potentially leading to episodes of inflammation in various organ systems. In a third type of the disorder—HAE type III—”the C1 esterase level is normal but there is a genetic mutation on the gene that encodes coagulation factor XII.”

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The incidence of HAE is difficult to establish because of mis- and underdiagnosis of the condition. Most patients with HAE experience their initial attack in childhood or adolescence.

Read more about experimental therapies for patients with HAE

Among individuals with HAE, the deficiency in C1-INH is due to the disorderly production of the receptor bradykinin, which plays a key role in vasopermeability. In fact, this vascular permeability permits the bradykinin receptor to help alleviate inflammation.

If the bradykinin receptor becomes uncontrolled because of a deficient or nonexistent C1-INH receptor, this can result in swelling in the deep layers of the soft tissue dermis. When this occurs, an individual’s symptoms can mimic those of a severe allergic reaction, including swollen eyes, lips, tongue, face, and extremities. Certain key signs and symptoms of HAE, however, can distinguish the disorder from an allergic reaction; appropriate testing will allow for the correct diagnosis.

Because the patient described had a history of recurrent HAE episodes, she arrived at the ED with her medication. She reported no known allergies, as well as no other possible causes of her sore throat and difficulty swallowing. An oropharyngeal examination revealed an inflamed uvula. The rest of her physical examination was unremarkable.

The patient was treated with an intravenously administered 1000 mg dose of a C1 esterase inhibitor. Her symptoms improved after the treatment, and she was discharged home.

Read more about HAE diagnosis

In individuals with HAE, first-line treatment involves attenuation of the inflammation with C1 esterase replacement therapy. Such agents work by inhibition of the action or the formation of bradykinin. If evidence of airway compromise is observed, an emergent airway may be necessary.

Prophylactic treatment of HAE can involve the use of regular C1-inhibitor replacement therapy (the preferred treatment) or an androgen (ie, danazol or stanozol). In addition, lifestyle changes are critical in patients with HAE, such as the avoidance of known triggers, including certain infections, trauma, pain, mental stress, and changes in weather.

“Early diagnosis and treatment of HAE are critical in order to prevent . . . complications and improve quality of life for affected individuals,” the authors concluded.


Banerjee A, Bermudez N, Gould MB, Ramlatchan SR, Ganti L. Hereditary angioedema. Cureus. Published online July 18, 2023. doi:10.7759/cureus.42088