Background: Eliminating pseudoallergens is an important element of managing chronic spontaneous urticaria (CSU). Salicylic acid (SA) is a primary pseudoallergen in plant-based foodstuffs. Current dietary recommendations are not applicable in East Asia because data on the SA content of many vegetables and fruits commonly consumed in this region are lacking. Methods: We therefore determined the concentration of free SA in 79 popular vegetables and fruits frequently consumed in Taiwan using gas chromatography-mass spectrometry. Results: The SA content ranged from 0.09 to 2.3 mg/kg in the fresh vegetables examined, and from 0.01 to 0.48 mg/kg in the fruits. Conclusions: Data regarding the SA content of East Asian vegetables and fruits could help CSU patients limit their pseudoallergen consumption.

Background. Chronic urticaria (CU) is comprised of diverse phenotypes, and thus, a shift towards a precision medical approach is warranted in its management. Methods. This study enrolled 78 patients with CU. Serum erythrocyte sedimentation rate, hemoglobin, hematocrit, eosinophil count, IgE, antinuclear antibody (ANA), and serum diamine oxidase (DAO) levels of the patients were measured and were compared according to the patient’s response to second-generation antihistamines (sgAH), corticosteroids, leukotriene receptor antagonist (LTRA), H2 blockers, and low-histamine diet. Results. Age- and sex-adjusted logistic regression analysis showed that patients with duration of CU > 3 years (adjusted odd ratio aOR = 4.39 ) and a DAO   level < 10   U / mL ( aOR = 3.90 ) were significantly associated with a good sgAH response. Age > 50 years ( aOR = 0.02 ), duration of chronic   urticaria > 3 years (aOR =0.06), and an ANA   titer ≥ 1 : 80 ( aOR = 0.03 ) were significantly and inversely associated with corticosteroid response. A low-histamine diet response was significantly associated with LTRA response ( aOR = 67.29 ). In addition, a DAO level < 5.4   U / mL ( aOR = 71.95 ) was significantly associated with H2 blocker response. Furthermore, concomitant angioedema ( aOR = 10.56 ), multiple food triggers ( aOR = 11.69 ), and a DAO   level < 5.4   U / mL ( aOR = 3.78 ) were significantly associated with a low-histamine diet response. Conversely, dermatographic urticaria and a hematocrit   level < 36 % were significantly and inversely associated with low-histamine diet response. Conclusions. Several promising biomarkers were identified in this study to predict the efficacy of chronic urticaria treatment. DAO could be a novel biomarker for predicting the efficacy not only of dietary intervention but also for antagonists of H1 and H2 receptors.