Hereditary and Acquired Angioedema for Rheumatologists in India: Are We Missing the Diagnosis?

Bradykinin-mediated angioedema can broadly be categorised into hereditary angioedema (HAE) and acquired angioedema (AAE). Both HAE and AAE are grossly under-recognised in the country largely because of lack of awareness. Type 1 and 2 HAE is caused by pathogenic variants in the SERPING1 gene that codes for C1-inhibitor protein. Deficiency of C1-inhibitor protein leads to recurrent swelling episodes involving hands, feet, eyes, lips, tongue and genitalia. These episodes are typically not associated with itching or urticaria. Involvement of the larynx leads to a potentially life-threatening episode of choking and, in the past, the mortality because of laryngeal edema used to be as high as 30%. AAE is usually associated with lymphoreticular malignancies; predominantly B cell lymphomas and systemic lupus erythematosus. Angioedema often precedes the diagnosis of primary illness. The clinical features of both AAE and HAE are similar. However, AAE should be suspected in patients with onset of disease in older age. Management of HAE is broadly categorised into three types: on-demand therapy and short-term and long-term prophylaxis (LTP). Patients with AAE also need management of the underlying disease with immunosuppressants. This review focuses on clinical manifestations, diagnostic evaluation, and clinical mimics of HAE and AAE from the perspective of a rheumatologist. The review also briefly discusses the management principles of HAE and AAE.