An Unusual Case of Acquired Angioedema and Monoclonal Gammopathy of Renal Significance in a Middle-Aged Caucasian Female.

Acquired angioedema due to deficiency of C1 esterase inhibitor is also called acquired angioedema and is abbreviated as C1INH-AAE. It is a rare syndrome of recurrent episodes of angioedema, without urticaria, and in some patients, it is associated with B-cell lymphoproliferative disorders. Kidney involvement is rare in this condition. The monoclonal immunoglobulin secreted by a nonmalignant or premalignant B-cell or plasma cell clone, causing renal damage that represents a group of disorders which are termed as monoclonal gammopathy of renal significance (MGRS). In this article, we report a rare case of acquired C1 esterase deficiency angioedema and acute kidney injury with renal biopsy-proven MGRS. We present a 64-year-old Caucasian woman who presented with 2 weeks of recurring urticaria and new onset of acute kidney injury. She was diagnosed with monoclonal gammopathy-associated proliferative glomerulopathy through kidney biopsy, and serological workup came back positive for C1 esterase deficiency, implying acquired angioedema. Acquired angioedema is a rare disease with systemic involvement. Recurrent allergic manifestations and acute kidney injury should prompt MGRS as a differential.