Saliva plays a crucial role in taste, chewing, speech, digestion, and oral health (1, 2). About 90% of saliva is produced and secreted by the major salivary glands (parotid, submandibular, and sublingual glands) (3). Salivary hypofunction increases the risk of oral diseases (2), including sialadenitis (4). Sialadenitis is defined as an inflammation or infection of the salivary glands that may affect the parotid, submandibular, and minor salivary glands (5). Among all salivary glands, the parotids are the most frequently affected site by this inflammation, known as parotitis (6). Parotitis can be either acute or chronic and is classified as suppurative, caused by bacteria from the oral cavity (5, 7, 8), or non-suppurative, resulting from viral, autoimmune, or metabolic disorders (9). In addition to other contributing factors, these include dehydration, malnutrition, and certain medications (10, 11). Hence, the clinical presentation is essential for determining the optimal treatment option (12).

Acute suppurative parotitis (ASP) often affects older adult men with poor oral hygiene and inadequate oral intake, leading to decreased saliva production (13). Before the modern antibiotic era, ASP had a mortality rate of 50%, making it a serious postoperative complication (14, 15). However, the frequency of diagnosis has decreased to 0.02%–0.04% of all hospital admissions (16, 17). About 80% of cases of acute suppurative parotitis are caused by Staphylococcus Aureus infection, and most patients report swelling, fever, and pain (16).

Salivary flow rate is considered a major risk factor for parotitis (18). Sialoliths, duct strictures, foreign bodies, or external pressure on the Stensen duct can lead to chronic parotitis due to reduced salivary secretion (19). Eventually, the lobular structure is progressively destroyed as a result of acinar atrophy, fibrosis, and fatty tissue deposition (19–21). Sialogogues, mouthrinses, analgesics, and antibiotics are recommended as the initial treatment approach (22). However, this treatment strategy fails in 50% of patients (19), suggesting that parotidectomy is a safe and effective treatment for patients with severe and unmanageable symptoms (23, 24).

Juvenile recurrent parotitis (JRP) is the second most common inflammatory gland disease of childhood, after mumps (25, 26). This condition is common in children aged 3–6 years and typically resolves by puberty (18, 27).

Few studies have documented cases of parotitis in Saudi Arabia. For instance, one study reported an 83-year-old patient developing parotitis after a week of non-invasive ventilation (28). Another described three cases aged 82, 77, and 47 years, all associated with Sjögren's syndrome (29). Additionally, a study noted an 8-year-old who experienced multiple JRP attacks over two years (30). Albosaily identified 191 parotidectomies for nine non-malignant conditions, including chronic parotitis, which accounted for only 2.6% of all cases (31). Since information on parotitis in Saudi Arabia is limited, this study aimed to explore the prevalence, demographic patterns, and temporal trends of parotitis among Saudi patients.

Due to the paucity of literature on parotitis in Saudi Arabia, this study primarily aimed to investigate the prevalence and characteristics of parotitis among Saudi patients. This multicenter analysis of patients treated within the NGHA health system, the largest integrated provider network in Saudi Arabia, revealed several key findings. First, 1,340 cases of parotitis were recorded across all age groups over 8 years. The total number of patients in this cohort is relatively high and comparable to that of another cohort, except that their population consisted of children over 10 years old (n = 1,017) (40). To our knowledge, most information on all forms of parotitis (acute, chronic recurrent, and JRP) found in the literature is based on case studies or specific populations with small sample sizes (17, 30, 41, 42). Second, several studies have reported an increased in the number of parotitis in males than in females (26, 40, 43), consistent with our findings in this study. Third, approximately 50% of the study population was inpatients, suggesting various underlying factors, including non-invasive ventilation, hospitalization, the severity of parotitis, or chronic illnesses (e.g., autoimmune disorders and metabolic disorders), among those aged 40–60 years.

For example, our recent study reported 543 Sjögren's syndrome patients from the NGHA, with a mean age of 34, within a similar timeframe (44). We also found 375 patients with sialolithiasis at the same hospital, with a higher prevalence in males than females (45). The high prevalence of Sjögren's syndrome and sialolithiasis may contribute to parotitis in adults; however, further investigation is needed to confirm this observation. According to a recent meta-analysis, Saudi Arabia was identified as the country with the highest prevalence of type 2 diabetes mellitus (T2DM), with a rate of 16.4% between 2000 and 2023 (46). Based on this information, we also propose that T2DM may be another factor involved in the development of parotitis in some adult cases, as T2DM is associated with dry mouth and decreased salivary flow (47), which is a key factor in parotitis (48, 49). However, limited data on comorbidities restricted the analysis of the factors mentioned above, which might have helped identify those potentially associated with parotitis.

Interestingly, the highest proportion of cases was underweight (36.67%), followed by obese (19.2%), suggesting that abnormal BMI may contribute to parotitis. Malnutrition is a risk factor, and weight loss is a symptom of parotitis (7). We propose that inadequate food and water intake may play an indirect role in the pathogenesis of parotitis, as food stimulates salivary secretion through chewing, smelling, and tasting (1, 50). In contrast, water prevents the sensation of thirst and dry mouth, thereby lowering the risk of oral diseases (51). We also hypothesize that elevated BMI is implicated in reduced salivary flow, which can subsequently lead to sialolithiasis (45, 52, 53) and, eventually, parotitis. Given the exploratory nature of this study, BMI characteristics were demonstrated; however, a more comprehensive investigation is necessary to determine its impact on parotitis. Moreover, medications diminishing saliva production, such as other antipsychotics, anticholinergics, antidepressants, antihistamines, and anti-Parkinsonian medications, might contribute to parotitis (10, 41, 54). Nonetheless, this remains a preliminary suggestion that requires further research for confirmation, as the limited data on medications in this study restricted the ability to assess its link with parotitis.

Indeed, dehydration is the hallmark of parotitis (13, 41, 55). A study has shown an association between body dehydration and reduced parotid salivary flow rate (56). In this context, a study showed that 38.7% of Saudis consume less than 1 L of water daily (57). By linking these pieces of information, we assume that dehydration could be an additional contributor to parotitis. It also highlights the need to raise awareness among the Saudi public about the importance of increasing water intake to prevent parotitis and other oral health-related issues. If we consider all the abovementioned factors, it becomes clear that they may play a direct or indirect role in reducing salivary flow, thereby increasing saliva stasis and facilitating the ascent of bacteria from the oral cavity to the salivary gland ducts (7, 9, 11). Herein, we highlighted the significance of dehydration, although it was not the main focus of this study due to its role in developing parotitis.

Sialadenitis generally accounts for only 10% of all salivary gland diseases in children; however, it ranks second among inflammatory salivary gland diseases in childhood, after mumps. Parotitis is estimated to be 10 times less common in children than in adults (58). Although it is a well-recognized condition, its etiology remains unclear (59). Furthermore, the most common sign of mumps in children is parotitis (60–62). The median effectiveness of the Measles-Mumps-Rubella (MMR) vaccine in preventing mumps has been reported to range from 66% to 95% with two doses (61–64). Nevertheless, the Centers for Disease Control and Prevention (CDC) reported 6,369 mumps cases in 2016 and 6,109 cases in 2017 in the United States (65). A study also found that mumps cases are more frequent among vaccinated individuals (66). It has been suggested that the occurrence of mumps is associated with living situations (40, 67), secondary vaccine failure, or waning immunity (40). Based on this information, an extended analysis is needed to determine whether JRP, mumps, or other factors contributed to the high prevalence of parotitis among children and adolescents.

Several studies have demonstrated an association between parotitis-like symptoms and COVID-19 in children and adults (68–70). In contrast, our data showed no significant changes in the occurrence of parotitis cases during the study period or even throughout the pandemic.

By early 2023, around 70% of the Saudi population had received at least one COVID-19 vaccine dose, and more than 30% had received booster doses (71, 72). This could justify the reduction of parotitis cases during this period, suggesting that COVID-19 may not be directly associated with parotitis.

Geographic heterogeneity requires careful interpretation. Riyadh accounted for two-thirds of cases (66.1%) and served as the reference region; all other regions showed significantly lower adjusted rates, with the smallest IRR in Taif (0.03). Because NGHA's largest tertiary facilities and referral hubs are concentrated in the central region, these contrasts likely reflect referral centralization and differential access to subspecialty care, not necessarily true differences in community frequency rate. Nonetheless, the pattern is operationally critical: it emphasizes the need for equitable diagnostic capacity and standardized care pathways across sites, particularly for emergency assessment and timely imaging or otolaryngology consultation.

The NGHA system provides an ideal lens for examining these patterns. It is considered one of the largest integrated healthcare networks in Saudi Arabia, serving military personnel, their dependents, and a sizable civilian population across multiple tertiary hospitals in Riyadh, Jeddah, Dammam, Madinah, and Taif (73). Its electronic health record platform encompasses approximately 15% of all treated Saudi patients, making it the most comprehensive longitudinal clinical data source currently accessible for population-based epidemiologic research within a unified health system (74). Although NGHA data do not represent the entire Saudi population, they capture a demographically and geographically diverse subset that mirrors major regional variations in access, disease burden, and referral patterns.

Although the study is the first to report the prevalence of parotitis from one of the largest tertiary facilities and referral hubs in Saudi Arabia, several critical limitations were encountered during data collection. First, none of the parotitis types has been documented in the medical records, which limited our ability to characterize each type and forced us to discuss the condition in general terms. Secondly, missing variables related to blood tests, comorbidities, and medications hindered a thorough understanding of how these factors influence parotitis in children, middle-aged patients, and the older adult. In addition, the absence of a denominator population hindered true incidence calculation. Moreover, a possible referral bias might have existed since NGHA is a tertiary care center, which limits the generalizability of these findings.

To our knowledge, this is the first study of this design to investigate the frequency rate of parotitis in the Saudi population. The data revealed a high prevalence of parotitis among children and adolescents compared to adults in Saudi Arabia. In addition, most of these patients were inpatients, indicating the severity of the disease or other unspecified factors. Moreover, the majority of the reported cases were either underweight or obese, underscoring the need for further evaluation to understand how BMI relates to parotitis. Since dehydration is a key element in the development of parotitis, public awareness regarding the importance of adequate hydration for oral health is essential. In addition, the lack of information on parotitis in the medical records, including its type, blood parameters, comorbidities, and medications, is likely due to the rarity of the disease. However, it highlights the importance of clinical awareness of thorough documentation, which helps identify risk factors and inform prevention. In addition, the profound geographic inequities in diagnosis imply the need for standardized diagnostic protocols across regions to reduce variation. Despite the descriptive and epidemiological nature of this study, it exposed the gaps in this field, creating opportunities for future research directions.