Clinical Features, Diagnosis, and Treatment of Eosinophilic Sialodochitis: A Systematic Review of the Literature

Eosinophilic sialodochitis is an under-recognized obstructive inflammatory disorder of the major salivary ducts that has been described under heterogeneous terms, including allergic parotitis, fibrinous sialodochitis, and Kussmaul disease. We systematically reviewed the literature to summarize nomenclature, clinical presentation, diagnostic assessment, treatment, and consistency with proposed diagnostic criteria. We searched six bibliographic databases from inception to December 2025, complemented by Google Scholar and citation tracking. Studies describing eosinophilic sialodochitis or related entities were included irrespective of language. Data were synthesized descriptively because of marked heterogeneity. Seventy-nine studies involving 387 patients were included, comprising 64 full-text reports and 15 conference abstracts or posters. Most publications were case reports or case series. Recurrent parotid and/or submandibular swelling, eosinophil-rich salivary mucus plugs, ductal dilatation or stenosis, and frequent atopic comorbidity were the most characteristic findings. Eosinophils were identified in salivary mucus in 53 of 58 studies reporting local samples. Full compliance with published diagnostic criteria varied markedly, from 45 of 79 studies using the Baer framework to 2 of 79 using the Carey framework, while no study fully satisfied the Zhao framework. Treatment was usually multimodal and included antihistamines, corticosteroids, intraductal irrigation, sialendoscopy-assisted procedures, and, in selected refractory cases, biologic agents targeting type 2 inflammation. The available evidence supports eosinophilic sialodochitis as a distinct but incompletely standardized clinicopathological entity. Interpretation is limited by heterogeneity, incomplete reporting, and low-certainty evidence. Standardized definitions and minimum reporting items are needed to improve diagnostic certainty and comparability.