Clinical and Laboratory Characteristics of Patients with Chronic Spontaneous Urticaria in a Vietnamese population.

This study aims to investigate the clinical and laboratory characteristics of patients with type IIb autoimmune Chronic Spontaneous Urticaria (CSU) in a Vietnamese population and how this correlate with results of the Basophil Histamine Release Assay (BHRA). A cross-sectional, single-center study was conducted with 388 CSU patients aged 16 years or older at the Vietnam National Dermatology and Venereology Hospital, from June 2023 to March 2024. Clinical data were collected, and laboratory tests were performed. Patients also underwent the Autologous Serum Skin Test (ASST) and BHRA. A multivariate logistic regression model was performed to identify factors associated with a positive BHRA. Of the 388 CSU patients, 60.3% had new onset symptoms, 34.0% had angioedema, and 12.6% had comorbid dermographism. Laboratory results indicated that 11.4%, 5.9%, and 1.8% of patients had elevated CRP levels, low total serum IgE levels, and basopenia, respectively. Additionally, elevated IgG anti-TPO levels, positive ANA, and positive ASST were found in 10.6%, 11.4%, and 57.2% of patients, respectively. There were 9.5% who tested positive for BHRA. Multivariate logistic regression identified UAS7 score (OR=1.047, p=0.017), low basophil levels (OR=6.749, p=0.027), and low total serum IgE (OR=3.391, p=0.039) as significant predictors of BHRA positivity. Our results identified key clinical and laboratory characteristics associated with type IIb autoimmune CSU in Vietnamese patients. Higher UAS7 scores, basopenia, and low IgE levels were significant predictors of BHRA positivity.