A follow-up survey of patients with acquired angioedema due to C1-inhibitor deficiency

Abstract

Background: Acquired angioedema due to C1-inhibitor deficiency (C1-INH-AAE) is a rare form of bradykinin-mediated angioedema. It is diagnosed by complement testing; its treatment consists of the management of angioedema (AE) attacks and of underlying disease.

Objective: Evaluate the results of the clinical follow-up of patients with C1-INH-AAE.

Methods: Between 1999 and 2020, 3938 patients with angioedema were evaluated, and 17 diagnosed with acquired C1-INH deficiency were followed-up.

Results: Mean age of the 17 patients was 61 years at diagnosis. In 33%, ACE inhibitors provoked AE attacks. Autoantibodies against C1-INH were detected in 10 patients at diagnosis and in a further patient during follow-up. The AE attacks involved the skin in 70.6%, the upper airways in 41.2% and the tongue/lip in 52.9% of patients. Twelve of the 17 patients had an underlying condition, mainly (n = 11) lymphoproliferative disease. In 10 patients diagnosed with a haematological disorder, AAE symptoms preceded the onset of the latter. One patient has not experienced an AE attack since diagnosis. Twelve patients were treated for angioedema attacks, and 32% of the attacks required acute treatment. PdC1-INH was used to relieve AE attacks, and rituximab for the treatment of underlying disease (in six patients). Six patients had multiple AE attacks before any treatment. The symptom-free period increased in five patients after the on-demand administration of pdC1-INH concentrate and following treatment of the underlying disease in two patients.

Conclusion: Early diagnosis of C1-INH-AAE and underlying disease is indispensable to reduce disease burden by introducing appropriate, individualized treatment and regular follow-up.

Keywords: C1 inhibitor deficiency; acquired angioedema; angiotensin-converting enzyme inhibitors; lymphoproliferative disease; rituximab.