Parotid gland swelling following mouthrinse use

Background:  Unilateral or bilateral swelling of the parotid gland is a reported side effect of rinsing the mouth with chlorhexidine. Although the incidence rate is extremely low, there have been several case reports on this topic and the authors of these reports have suggested several explanations for the mechanism of this complication.
Methods:  In this report, two cases of parotid gland swelling are discussed. Both patients developed unilateral parotid swelling following the use of a mouthwash, case 1 after using a chlorhexidine mouthwash following flap surgery and case 2 after using a hexetidine mouthwash in an approved clinical trial that was testing different mouthwashes.
Results:  In both of the cases, differential diagnoses were made to explain the cause of the parotid swelling. However, discontinuing use of the product resulted in an eventual complete resolution of symptoms in both patients.
Conclusions:  Swelling of the parotid gland following use of a mouthwash has previously been reported, although previous reports found this side effect only in patients who used chlorhexidine mouthwashes. This complication has therefore been informally linked to chlorhexidine. The present case report questions this hypothesis and suggests that parotid gland swelling may not be related to the type of mouthwash used, but may instead be a consequence of the rinsing action itself.