Angioedema without urticaria in 929 patients: Description and proposal for a diagnostic approach

Abstract

Rationale Angioedema without major urticaria flares is poorly characterized and few data exist on the underlying etiopathogenetic mechanisms. Here we report our experience on this condition and propose a diagnostic-therapeutic approach. Methods 929 consecutive patients were examined at our outpatient clinic for recurrent angioedema without urticaria between 1993 and 2002. Known causes of angioedema were identified by clinical history with detailed information about personal and familial allergies, relationship of angioedema to potential causative agents, complete physical examination, routine laboratory tests (blood cell count, protein electrophoresis, erythrosedimentation rate, stool for ova and parasites, pharyngeal and urine cultures, sinus and dental film, anti-tissue autoantibodies, rheumatoid factor), complement parameters (C1 inhibitor, C4, C1q). Further testing was done when pertinent. When all was negative, response to H1-antihistamine was considered. Results According to our testing angioedema were classified as follow: related to external agents (drugs, insect stings, food) 209 (22.5%) (85 of them were related to treatment with an ACE-inhibitor); associated to autoimmune diseases or infections 77 (8.2%); hereditary C1 inhibitor deficiency 183 (19.6%); acquired C1 inhibitor deficiency 14 (1.5%); idiopathic histaminergic 253 (27.2%), idiopathic non histaminergic 40 (4%). 153 patients (16.4%) dropped out from the study and could not be classified. Conclusions Based on the frequency of the different diagnosis we propose the following progression of testing: 1. anamnestic identification of causative agents, 2. testing for complement abnormalities, 3. H1 antagonist treatment, 4. complete diagnostic workup.