Salivary Gland Manifestations of Long COVID: A Case Report and Literature Review

Background: While acute coronavirus disease 2019 (COVID-19) infections of the oral cavity, with clinical signs such as taste loss, dry mouth, and mucosal lesions, are well-established health problems, involvement of the oral cavity as a sign of long COVID is poorly understood. One of the organs in the oral cavity that is prone to the virus is the salivary gland. Case presentation: We describe the case of an elderly patient with severe generalized xerostomia and left-sided facial swelling involving the submandibular gland, an uncommon presentation, as the parotid gland is typically involved COVID-19 infections. Ultrasound demonstrated marked ductal dilation without glandular tissue changes. The absence of other causes of sialodochitis, together with a history of repeated COVID-19 infections, led to the diagnosis of post-COVID sialodochitis. Management options were limited by the patient's frailty and polypharmacy. Nevertheless, conservative symptomatic treatment led to clinical recovery, with no evidence of progression to bacterial or necrotizing sialadenitis. Conclusions: This case demonstrates that COVID-19 infection and its history should be included in the differential diagnosis of sialadenitis. Along with the clinical case presentation, a narrative review of similar studies on COVID-19-associated salivary gland disease was conducted, spanning molecular and post-mortem evidence, acute clinical cases, and post-COVID sequelae.