Sialadenitis is most common in the parotid gland and typically occurs in Patients in their 50s and 60s Chronically ill patients with xerostomia Patients with Sjögren syndrome Adolescents and young adults with anorexia Children (age 1 to18 years) with juvenile recurrent parotitis of undetermined etiology The most common causative organism is Staphylococcus aureus; others include streptococci, coliforms, and various anaerobic bacteria.