BACKGROUND: Chronic inducible urticaria (CIndU) is characterised by itchy wheals and/or angioedema that only appears when triggered by a specific stimuli. The real-world rate of CIndU across Europe (EU) and Central/South America (C/SA) is currently unknown.
METHOD: Data from patients with CIndU residing in the EU and C/SA enrolled in the ongoing observational AWARE study collected at enrolment (visit 1) were used. Patients were aged 18 years or older and were refractory to at least one course of H1-antihistamine treatment. Diagnosis at study entry was assessed, alongside perceived disease control (measured by the Urticaria Control Test [UCT]; scores below 12 indicate poor control) and quality of life (QoL) (measured by the Dermatology Life Quality Index [DLQI]). The data were split into regions for comparison: Europe (United Kingdom; Nordic countries [Sweden, Norway, Denmark]; Southern Europe [Belgium, France, Portugal, Spain, Italy, Greece]; Germany; and Russia) and C/SA (Central [Guatemala, Honduras, Costa Rica, Dominican Republic, Panama]; South [Colombia, Peru, Brazil, Argentina]). Descriptive statistics are reported here overall and by region; comparisons among subregions will be presented.
RESULTS: Overall, 26% (n=1,118) of patients with chronic urticaria (N=4,226) were diagnosed with CIndU at study entry. Of these patients, 31% had angioedema at study entry or within the past 6 months and 77% had CIndU comorbid to chronic spontaneous urticaria (CSU). The rate of CIndU diagnoses was higher in C/SA than in EU (33% vs. 26%), but the rate of angioedema and rate of CIndU comorbid to CSU was similar in both regions. Rates of light/solar, vibratory, aquagenic, and contact urticaria were low (range: 0.7%-6.2%). Patients in C/SA had a higher rate of symptomatic dermographism (53% vs. 44%) and delayed pressure urticaria (30% vs. 25%) but a lower rate of cold urticaria (10% vs. 18%) and cholinergic urticaria (8% vs. 18%) compared with EU patients. Differences were also identified within subregion comparisons. UCT scores identified poor disease control in 77% of CIndU patients (C/SA 84% vs. EU 76%). Most patients reported a moderate (25%), very large (26%), or extremely large effect (7%) of CIndU on QoL (DLQI); ratings were comparable between regions.
CONCLUSION: CIndU is commonly associated with CSU, is uncontrolled in most patients, and can be severely disabling (as shown by angioedema rates and the effect on QoL).
