Allergic disorders and their risk factors in primary Sjögren's syndrome

OBJECTIVE: This study aimed to evaluate the prevalence of allergic disorders in patients with primary Sjögren's syndrome (pSS), compare it with that of patients with rheumatoid arthritis (RA), and examine the risk factors in patients with pSS. METHODS: We retrospectively examined the records of patients diagnosed with pSS and RA who regularly visited our department between 2010 and 2020. Allergic disorders included drug allergy, food allergy, allergic contact dermatitis (ACD), allergic rhinitis (AR)/allergic conjunctivitis (AC), and asthma. RESULTS: Patients with pSS (292 patients) had a higher prevalence of food allergy, drug allergy, and AR/AC than those with RA (413 patients). The multivariate analysis revealed that patients with pSS who had drug allergy had a higher prevalence of food allergy, higher eosinophil levels, and higher positivity rates of anti–SS-related antigen A (SSA) antibodies than those without drug allergy; those with food allergy had a higher rate of ACD than those without food allergy and vice versa; those with AR/AC had a higher rate of ACD and asthma and higher eosinophil levels than those without AR/AC; those with asthma had a higher rate of AR/AC than those without asthma. CONCLUSIONS: Patients with pSS had a higher prevalence of allergic disorders than those with RA. Among patients with pSS, the risk factors for drug allergy were food allergy, higher eosinophil levels, and positivity for anti-SSA antibodies, the risk factor for food allergy was ACD and vice versa, the risk factors for AR/AC were ACD, asthma, and high eosinophil levels, and the risk factor for asthma was AR/AC.