I recently saw a 75 year-old woman who experienced her first ever episode of angioedema after a dental visit. She suspected local anesthetic allergy, but I ordered labs which disclosed very low C1 esterase inhibitor - both functional and protein levels, as well as low C4. Subsequent labs disclosed undetectable C2 (between episodes) and a very low C1q, all pointing to acquired deficiency. However, the patient reports a family history of recurrent angioedema. She has subsequently experienced several episodes of unexplained severe abdominal pains, and another episode of facial angioedema. She was referred to H/Onc for evaluation of possible underlying causes. Is it possible she has hereditary angioedema with a low C1q and such late onset? Is she a candidate for any of the new treatments available for hereditary angioedema? Is there any preventive treatment that can be used in acquired angioedema?


Thank you for your inquiry.

With the information available, it is difficult to make a definitive statement as to whether your patient has acquired or hereditary angioedema, and of course there is even an outside possibility that she could have both. Nonetheless, fortunately, in many instances, except for the search of a cause for acquired angioedema, the issue is not of clinical significance as far as treatment is concerned since patients with acquired angioedema quite frequently do respond to drugs used to treat hereditary angioedema (1, 2). Therefore regardless I suggest that you initiate therapy as one would for the hereditary variety.

Thank you again for your inquiry and we hope this response is helpful to you.

1. Levi, et al. Self-administration of C1 inhibitor concentrate in patients with hereditary or acquired angioedema caused by C1-inhibitor deficiency. J Allergy Clin Immunol 2006 (April); 117(4):904-908.

2. Bork and Witzke. Long-term prophylaxis with C1 inhibitor concentrate in patients with recurrent angioedema caused by hereditary and acquired C1 inhibitor deficiency. J Allergy Clin Immunol 1989 (March); 83(3):677-682.

Phil Lieberman, M.D.

Close-up of pine tree branches in Winter Close-up of pine tree branches in Winter