Thank you for your inquiry.
If this patient does indeed have urticaria, I would not in any way be suspicious of a C1 esterase inhibitor deficiency syndrome. Urticaria is not a component of angioedema related to C1inhibitor deficiency However, C1 inhibitor deficiency syndrome can oftentimes occur in a patient who is in their middle years. It can be of the acquired type which is oftentimes associated with a low C1 as well. But, no type of C1 inhibitor deficiency syndrome is characterized by urticaria. These patients experience angioedema only.
However, tests for C1 inhibitor deficiency syndrome are commonly available and easy to obtain; therefore should there be any question, I would simply order the assays (C1 inhibitor functional assay and C4).
Thank you again for your inquiry and we hope this response is helpful to you.
Phil Lieberman, M.D.