Acquired C1 esterase inhibitor deficiency

Ann Intern Med. 2000 Jan 18;132(2):144-50. doi: 10.7326/0003-4819-132-2-200001180-00009.


Acquired C1 esterase inhibitor deficiency is a rare condition associated with autoimmune or low-grade lymphoproliferative disorders. Adults or elderly patients are most commonly affected. The diagnosis is suspected when patients present with recurrent angioedema and low serum levels of C4 with normal levels of C3. Low levels of C1q and low C1 esterase inhibitor activity confirm the diagnosis. In this paper, we summarize experience with 22 cases of acquired C1 esterase inhibitor deficiency in the context of a review of the published literature on diagnosis and treatment of this condition.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Adrenal Cortex Hormones / therapeutic use
  • Adult
  • Aged
  • Algorithms
  • Androgens / therapeutic use
  • Angioedema / drug therapy
  • Angioedema / etiology
  • Autoimmune Diseases / diagnosis
  • Autoimmune Diseases / drug therapy
  • Complement C1 Inactivator Proteins / deficiency*
  • Diagnosis, Differential
  • Edema / drug therapy
  • Edema / etiology
  • Epinephrine / therapeutic use
  • Female
  • Humans
  • Lymphoproliferative Disorders / diagnosis
  • Lymphoproliferative Disorders / drug therapy
  • Male


  • Adrenal Cortex Hormones
  • Androgens
  • Complement C1 Inactivator Proteins
  • Epinephrine