Clinical experience of a specialized urticaria outpatient clinic from a Portuguese UCARE

Background. Chronic urticaria (CU) is a frequent disease, with a prevalence of at least 1%. It is characterized by pruritic wheals, angioedema or both for a period longer than 6 weeks. Objective. Identify the demographic, clinical, laboratory and therapeutic profile of patients treated in a Portuguese Urticaria Center of Reference and Excellence (UCARE) and compare it with international series. Methods. Retrospective analysis of database of patients observed in a specialized urticaria outpatient clinic, from January 2017 through September 2019, of a UCARE center in Portugal. Demographic and clinical features, laboratory findings and pharmacological treatment were obtained from the records. Descriptive analyses were performed for all variables. Chi square and fisher's exact tests were applied to analyze the independence of variables and the fit of distribution. P less than 0.05 was considered significant. Results. During this period, 477 patients were observed, of whom 429 (90%) were diagnosed with chronic urticaria. Mean age (years) at the onset of symptoms was 43.7 (standard deviation (SD) 17.6, range 6-88) and at diagnosis 46.7 (SD 17.8, range 6-88) resulting in an average diagnostic delay of 3 years (range 0-25). Median follow-up period since first attendance in the specialized outpatient clinic was 1.7 years (interquartile range (IQR) 0.79, range 0.1-2.75) . Concerning the whole group of CU patients, 347 (81%) had chronic spontaneous urticaria (CSU) - 79% female, 39 (9%) had isolated chronic inducible urticaria (CIndU) and 43 (10%) had CSU with CIndU. Autologous serum skin test (ASST) was done in 76 patients (positive in 24 (32%)) and basophil activation test (BAT) was done in 38 (positive in 13 (34%)). At the moment of study, 204 (48%) of CU patients were medicated with a second-generation H1-antihistamine (sgAH) daily (first-line therapy), 99 (23%) with sgAH up to four times the standard dose (second-line therapy) and 126 (29%) with omalizumab (third-line therapy). Additionally, 7 (2%) patients were completing a short course of systemic corticosteroids for management of disease exacerbation. Disease control was achieved in 316 of CSU patients (81%). Conclusions. Referral to a specialized urticaria outpatient clinic is important for a proper assessment of the disease and adequately symptom control.