D2.357 - Characterizing chronic histaminergic angioedema and chronic urticaria with angioedema, a multicenter Italian experience

Chronic spontaneous urticaria (CSU) is a common disorder characterized by the recurrence of wheals and/or angioedema for more than 6 weeks. About 37% of patients have wheals and angioedema (CSU-AE) and around 6% of patients only have angioedema. This type of angioedema is mast cell-mediated (MC-AE). Isolated recurrent MC-AE is also often mentioned as chronic histaminergic angioedema (CHA). As few data comparing CHA and CSU-AE are published, we analyzed the differences between demographic and clinical characteristics of these populations.

A multicenter, observational, retrospective study, involving eight Allergology Centers in Lombardy, Italy, including 44 CHA and 34 CSU-AE pediatric and adult patients was performed. Data about sex, age, comorbidities, inflammatory markers, complement fractions, blood eosinophilia, use of ACE inhibitors or angiotensin receptor blockers, site of angioedema attacks, therapy used to treat attacks, frequency of attacks at diagnosis, after 6 months of therapy and after 12 months of therapy were collected and analyzed.

Age and male/female ratio were similar in both groups. A higher rate of atopy was found in CSU-AE than in CHA (58.8% vs 29.5%, p=0.01). Hypothyroidism and anti-thyroid antibodies were more frequently detected in the CSU-AE population than the CHA population (respectively 29.4% and 26.5% vs 11.4% and 6.8%, p=0.045 and p=0.026). Face was the site majorly involved in both populations. Tongue angioedema was more reported in CHA than in CSU-AE (22.7% vs 2.9%, p=0.019). In CHA patients, upper airway involvement was reported mainly in male patients (p=0.02). Monthly frequency of angioedema attacks at diagnosis was higher in the CSU-AE group than in the CHA group (2.1 vs 1.45, p=0.045). Rates of attacks in CHA patients who used omalizumab or tranexamic acid in addition to antihistamines were higher than other CHA patients (2.1 vs 1.27 and 0.57 vs 0.18, p=0.011 and p=0.028). No other differences between groups were recorded.

Some characteristics may differentiate CHA from CSU-AE, as the latter experience higher rates of atopy, hypothyroidism and anti-thyroid antibodies positivity, as well as higher frequency of attacks and less tongue involvement. Clinical differences between CSU phenotypes represent the heterogeneity of this disease and their assessment may provide insights for better patient care and prognosis.