Acquired angioedema--occurrence, clinical features and associated disorders in a Danish nationwide patient cohort.
BACKGROUND
The prevalence of acquired angioedema (AAE) is hitherto unknown and, to date, less than 200 patients have been reported worldwide. AAE is associated with lymphoproliferative conditions and autoantibodies against C1 inhibitor (C1INH). Rituximab (RTX) is increasingly used in the treatment of AAE patients.


METHODS
A nationwide study of AAE patients was performed in Denmark. Clinical features, associated disorders, treatments and outcomes were registered.


RESULTS
Eight AAE patients were identified. The diagnostic delay was on average 1 year and 8 months. Patients were treated with C1INH concentrate or icatibant on demand. Six patients were diagnosed with a clonal B-cell disorder during follow-up, on average 2.5 years after the first swelling. Two patients had monoclonal B-cell lymphocytosis (MBL). Two patients received RTX.


CONCLUSIONS
AAE is a rare condition occurring in less than 10% of patients with C1INH deficiency in Denmark. AAE is highly associated with haematologic disorders, and we recommend yearly follow-up visits with clinical examination and blood tests including flow cytometry to diagnose B-cell conditions at an early stage. We report 2 patients with AAE and associated MBL, which is a benign expansion of clonal B lymphocytes. MBL can be the precursor of chronic lymphocytic leukaemia or is associated with non-Hodgkin's lymphoma. If angioedema is poorly controlled with standard treatment regimens, we suggest treatment of the associated haematologic disorder. Based on a review of the literature and our own data, we recommend therapy with RTX, especially in patients with anti-C1INH autoantibodies.
Department of Dermatology and Allergy Centre, Odense University Hospital, Odense, Denmark.
Anette
A
Bygum
Hanne
H
Vestergaard
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000368:Aged; D000369:Aged, 80 and over; D000799:Angioedema / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology*; D058846:Antibodies, Monoclonal, Murine-Derived / Q000627:therapeutic use*; D001323:Autoantibodies / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D001920:Bradykinin / Q000031:analogs & derivatives / Q000627:therapeutic use; D015331:Cohort Studies; D003174:Complement C1 Inactivator Proteins / Q000276:immunology* / Q000378:metabolism; D050718:Complement C1 Inhibitor Protein; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D008218:Lymphocytosis / Q000276:immunology; D008297:Male; D008875:Middle Aged; D000069283:Rituximab
D000319:Adrenergic beta-Antagonists; D058846:Antibodies, Monoclonal, Murine-Derived; D001323:Autoantibodies; D003174:Complement C1 Inactivator Proteins; D050718:Complement C1 Inhibitor Protein; C469952:SERPING1 protein, human; D000069283:Rituximab; C065679:icatibant; D001920:Bradykinin