Angioedema without urticaria (suspected bradykinin-mediated angioedema)

Respiratory medicine and allergy · Symptom or situation · updated 2026-10-30

BioMG follows French guidelines. Adapt it to the guidelines and the tests available where you practise.

Frequency: Fewer than 1% of angio-oedemas are bradykinin-mediated; hereditary angio-oedema due to C1 inhibitor deficiency: about 1 per 50 000 inhabitants ^[1]

Recurrent angioedema without urticaria (not on an ACE inhibitor)

Laboratory tests (outside an attack)

C1 inhibitor: level
C1 inhibitor: function
C4
C1q (if onset after 40 with no family history)if neededSuspected angioedema due to acquired C1 inhibitor deficiency (person over 40, no family history): C1q is low in 70 to 90% of cases, whereas it is generally normal in the hereditary form ^[2].
Serum protein electrophoresis (if acquired deficiency suspected)if neededAcquired C1 inhibitor deficiency suspected or confirmed: it can be associated with a monoclonal gammopathy or a lymphoproliferative syndrome ^[2].

Detailed explanation and international comparison (in French): read it in English (machine translation)

Also consider

Probable mast-cell-mediated angio-oedema? The mast-cell form, the most frequent, falls under the page Urticaire chronique.

Do not order

C3 and CH50: useless for the diagnosis of hereditary angioedema ^[2].
C1 inhibitor measurement during an attack: useless, the tests are done between attacks ^[2].
C1q and anti-C1 inhibitor antibodies as first-line tests in a young person: to be reserved for suspected acquired deficiency ^[2].

Angioedema on an ACE inhibitor (or gliptin, sacubitril-valsartan)

Laboratory tests (away from an attack)

C1 inhibitor: level
C1 inhibitor: function

Detailed explanation and international comparison (in French): read it in English (machine translation)

Sources (9)