Background: Allergic rhinitis is manifested by watery discharge; however its clinical effect on the watery volume in the oral cavity is unknown. In addition, the low incidence of dry mouth due to treatment with the new generation antihistamines is based on subjective patients' reports only. This study aimed to examine the effect of loratadine and fexofenadine on the salivary gland function in patients diagnosed with allergic rhinitis compared to untreated allergic patients and healthy individuals.
Methods: A comparative observational study assessed parameters related to the patients' perception of dry mouth as well as clinically observed parameters in fexofenadine-treated patients (group A) and in loratadine-treated patients (group B). Allergic patients without pharmacological treatment (group C) and healthy individuals (group D) served as a double control in order to evaluate the effect of allergy itself on dry mouth. A total of 36 patients were enrolled.
Results: Patients in groups A and C reported the highest intensity of xerostomia. Sialometry values were significantly lower in these 2 groups compared to the healthy controls (p = 0.02 and 0.03, respectively). Average sialometry was over 0.2 ml/min in all groups and subjective dry mouth sensation ranged in the lower quarter of the visual analogue scale.
Conclusions: In this pilot study, patients diagnosed with allergy presented a significant difference in salivary flow rate compared to healthy controls. Unlike the effect of loratadine, fexofenadine-treated patients showed significantly lower salivary flow rates compared to healthy individuals. In all cases the intensity of dry mouth was low.