The attack localizations in C1 inhibitor deficient hereditary angioedema patients

Background Hereditary angioedema (HAE) is a rare autosomal dominant inherited disease characterized by recurrent angioedema episodes and classified as HAE with C1-inhibitor (C1INH) deficiency (HAE-C1INH) and HAE with normal C1-inhibitor (HAE-nlC1INH). It may involve the face, larynx, upper airways, trunk, gastrointestinal system, genital area, and extremities. The angioedema attacks are disabling, and laryngeal edema can lead to asphyxiation and death if it is not treated successfully. We aim to investigate the association between the attack localizations and complement parameters of HAE C1INH patients.Methods Patients with HAE-C1INH from Ege University Faculty of Medicine were included. Patients with HAE-nl-C1INH were excluded from the study. Data on the clinical records were obtained retrospectively. Sociodemographic data, age at disease onset, annual attack frequencies, attack localizations, and complement parameters were recorded.Results One-hundred patients were in the study group. Fifty four percent of them were female. The majority of patients were HAE-C1INH type I (87%). The mean age at disease onset was 12.01 ±7.04 years. Plasma C4 levels were normal in eight patients (8.16%). The most frequently involved localizations were extremities (91%), gastrointestinal system (89%), and genital area (85%). Having a facial attack and erythema marginatum were both found to be correlated with the occurrence of laryngeal edema. Laryngeal edema was seen in 83.8% of the patients with erythema marginatum (P=0.010), and 75.9% of the patients with facial attacks (P<0.001).Conclusion The correlation between erythema marginatum and laryngeal edema was not reported in previous studies. Due to the unpredictable and fatal nature of the laryngeal attacks, all HAE patients and physicians should be alert of the occurrence and emergency treatment of laryngeal edema. We recommend that C4 alone should not be used to exclude the diagnosis of HAE-C1INH. The laboratory work-up should also include C1 inhibitor levels and C1INH function analysis.