D1.260 - Clinical Characteristics and Hospitalization Patterns in Chronic Spontaneous Urticaria Patients in Bulgaria

Chronic spontaneous urticaria (CSU) is a mast-cell-mediated disease defined by recurrent itchy wheals and/or angioedema lasting >6 weeks. Unpredictable flares and associated physical and psychological symptoms impair daily functioning, sleep, and mental health, often causing anxiety and depression. CSU also carries a substantial socioeconomic burden due to healthcare use and lost productivity. Although typically managed in outpatient care, severe or uncontrolled cases may require hospitalization. In Bulgaria, access to advanced therapies, particularly biologic treatments, is limited due to lack of national reimbursement, and scarce real-world data on CSU-related hospitalizations underscore the need for country-specific evidence.

We performed a retrospective, single-center study of adults with diagnosed CSU admitted to our University hospital at least once between July 2022 and July 2024 to describe the clinical profile, treatment patterns, and hospitalization characteristics of Bulgarian CSU patients, with a focus on rehospitalization and barriers to advanced therapy. Data included demographics, disease duration, clinical features, comorbidities, laboratory markers, and treatments.

We analyzed 1,212 hospitalizations corresponding to 951 unique patients (mean age 47.5 years; 71.8% female). Admissions lasted at least 48 hours or until disease stabilization. Mean disease duration was 70.4 months with a mean of 6.7 flares per year and a mean current flare duration of 17.2 days. Wheals occurred in 92.3% of hospitalizations and angioedema in 83.9%, with 76.2% presenting both. Autoimmune thyroid antibodies were present in 20.0% and H. pylori infection in 17.7%. Mean IgE was 189.2 IU/mL and mean CRP 6.3 mg/L. For maintenance therapy, 38.3% received standard-dose second-generation H1-antihistamines, while 61.7% required up-dosing; biologic use before admission was low. Rehospitalization occurred in 101 patients (10.6%), accounting for 362 admissions (mean 3.58 per patient). 

Hospitalized CSU patients in Bulgaria have long disease duration, frequent flares, and a high burden of angioedema, with rehospitalization driven by persistent symptoms, multimorbidity, and inadequate control on updosed antihistamines. Hospital care is largely focused on short-term stabilization rather than sustained disease control. Despite eligibility for biologic escalation, use remains low because of limited reimbursement, contributing to repeated corticosteroid exposure and recurrent admissions. Improving access to efficacious therapy and strengthening outpatient follow-up for high-risk patients may help reduce rehospitalization and overall disease burden.