D1.256 - Chronic Inducible Urticaria in Real Life: A Single-Centre Retrospective Cohort

Chronic inducible urticaria (CIndU) is a heterogeneous urticaria triggered by physical or physiological stimuli and often coexists with chronic spontaneous urticaria (CSU). This study aimed to describe the distribution of CIndU subtypes, assess the use and diagnostic yield of provocation testing, and evaluate the impact of different treatment approaches on disease activity and control.

We retrospectively analyzed patients with CIndU (2022–2025) for demographics, subtypes, coexistence of CSU, provocation tests, treatment modalities, follow-up, laboratory findings, disease activity and control.

A total of 178 patients (143F/35M) were included, with a mean age of 40.7±13.3 years. The most common CIndU subtypes were pressure, heat, dermographic urticaria, followed by cold, cholinergic, aquagenic, and solar urticaria. Dermographic urticaria was the most frequent isolated subtype, while others were predominantly observed in dual or triple combinations (Figure-1a). CSU coexisted in 43.7%(n:76) of the patients.

Provocation testing was performed in 28.1%(n:50) of the patients, mainly in dermographic urticaria, with a 92% (n:46) positivity rate. (Table-1a).

Of the patients 59.6% (n=106) were treated with antihistamines alone, most commonly in those with dermographic, cholinergic, aquagenic, cold, and pressure urticaria. In contrast, 34.8% (n=62) received omalizumab, predominantly patients with solar and heat urticaria (Figure-1b).

Overall, 65.2% (n:116) of patients attended follow-up visits. Adherence was significantly higher in the omalizumab group than in patients receiving antihistamines alone (100% vs. 50.9%,p<0.001). Patients with coexisting CSU had higher basophil levels (p=0.04). Dermographic urticaria was associated with lower CRP levels (p=0.04) and higher basophil (p=0.01) and eosinophil counts (p=0.04).  

Among 116 patients with follow-up, the median urticaria activity score decreased from 21 (0–42) to 4 (0-30), while the median urticaria control test score increased from 7 (0–16) to 14 (0-16) (p=0.001). Improvements were greatest in pressure, heat and dermographic urticaria, and were not influenced by CSU coexistence or treatment modality (Table-1b).

Pressure, heat, and dermographic urticaria were the most common CIndU subtypes and often overlapped. Provocation testing was particularly valuable in dermographic urticaria. Across all subtypes, disease activity and control improved irrespective of treatment type or CSU comorbidity, highlighting the value of regular follow-up and targeted diagnostics.