Recurrent Submandibular Sialadenitis With Associated Submandibular Lymphadenopathy Secondary to Iodinated Contrast: A Case Report

Iodinated contrast media are essential diagnostic tools widely used in radiographic and computed tomography (CT) examinations, with millions of procedures performed annually. Although generally well tolerated, these agents can, rarely, cause adverse reactions, including hypersensitivity reactions, acute kidney injury, and contrast-induced sialadenitis (iodide mumps). Contrast-induced sialadenitis is an uncommon, benign reaction to iodinated contrast media that most frequently involves the parotid glands and is likely underrecognized. Submandibular gland involvement with associated cervical lymphadenopathy is particularly rare and may mimic infectious or obstructive salivary gland pathology. We report a case of a 64-year-old woman who developed acute bilateral submandibular swelling and pain three to four hours after iodinated contrast administration for a CT performed to evaluate acute abdominal pain. The patient had a history of similar, self-limited episodes following prior contrast exposure. Physical examination revealed diffuse submental and submandibular swelling with mild tenderness but no signs of infection or airway compromise. Ultrasound demonstrated bilateral submandibular gland enlargement with heterogeneous echotexture, increased vascularity, and reactive cervical lymphadenopathy. Based on the temporal relationship to contrast exposure, prior similar episodes, absence of infectious features, and supportive imaging findings, a diagnosis of contrast-induced submandibular sialadenitis was made. Symptoms improved rapidly with conservative management and resolved within two days. This case highlights the importance of recognizing contrast-induced submandibular sialadenitis as a rare but benign and self-limiting condition. Awareness of this entity can help clinicians avoid unnecessary antibiotics, corticosteroids, and extensive diagnostic workup. Proper recognition and documentation are also important for counseling patients about future contrast exposure and considering alternative imaging modalities when appropriate.