C1 inhibitor (C1-1NH) deficiency results in bouts of mucocutaneous ede
ma and may be inherited (hereditary angioedema) or acquired (acquired
angioedema). The syndrome of acquired angioedema, characterized by the
adult onset of angioedema and by the lack of evidence of inheritance
of the disease, may be associated with lymphoproliferative or other ma
lignant diseases (type I) or with the presence of autoantibodies to C1
-1NH (type II); this is a rare variant form of C1-1NH deficiency with
angioedema. We report hen a case of acquired C1-1NH dificiency with an
gioedema, hypotension and abdominal discomfort observed in a 71-year-o
ld man in whom complement abnormalities and autoantibodies against C1-
1NH have been observed and who was classified as having an autoimmune
C1-1NH deficiency. From the therapeutic point of view after resolution
of the acute attacks, high doses of tranexamic acid have been able, a
t first, to decrease the frequency and the severity of the symptoms, a
nd subsequently to provide a long symptom-free time.