Long-term clinical course of adult-onset idiopathic recurrent parotitis: a retrospective cohort study

A subset of adults experiences recurrent parotid swelling without childhood-onset disease, a demonstrable obstructive lesion, or clinically apparent immune-mediated sialadenitis. The natural history of this poorly characterized phenotype and the need for invasive treatment remain uncertain. We therefore described its long-term clinical course in patients managed without therapeutic procedures. We retrospectively identified adults evaluated at Peking University School and Hospital of Stomatology between April 2013 and May 2019 for at least two episodes of unilateral or bilateral parotid swelling. Patients with juvenile recurrent parotitis, salivary stones, structural ductal obstruction, radiation-related disease, specific infection, clinically suspected immune-mediated sialadenitis, tumors, or previous therapeutic procedures were excluded. All included patients received standardized advice on parotid massage, hydration, salivary stimulation, and oral hygiene, but no interventional treatment. Follow-up continued through June 2025. The primary outcome was clinical status at final follow-up. Among 113 screened patients, 56 met the eligibility criteria and 43 (76.8%) completed long-term follow-up. Their mean age at baseline was 41.7 ± 16.3 years; 30 (69.8%) were women. Mean follow-up was 9.4 ± 2.2 years. The median baseline annual episode frequency was 3.0 (IQR, 2.0–12.0; range, 1–365) episodes/year. At final follow-up, 30 patients (69.8%) had experienced no episode during the preceding 2 years, 7 (16.3%) had a reduction of at least 50% in annual episode frequency, and 6 (14.0%) had no improvement; none worsened. Swelling was reported by 43 patients (100%) at baseline and 13 (30.2%) at final follow-up; corresponding figures were 15 (34.9%) and 1 (2.3%) for pain and 11 (25.6%) and 2 (4.7%) for abnormal ductal secretion. No new clinical diagnosis of Sjögren disease, IgG4-related disease, or another autoimmune disorder was documented during follow-up. Adult-onset recurrent parotid swelling without an identified obstructive cause or clinically apparent immune-mediated disease followed a favorable long-term course in most patients managed without therapeutic procedures. Observation with supportive self-care may be a reasonable initial approach after appropriate diagnostic evaluation. Because this uncontrolled retrospective study did not include systematic immunological reassessment, it cannot establish treatment efficacy or exclude subclinical immune-mediated disease.