What are the possible causes of submandibular swelling in children?

Causes of Submandibular Swelling in Children

Submandibular swelling in children is most commonly caused by infectious lymphadenitis (from dental, tonsillar, or upper respiratory infections), viral sialadenitis (especially mumps), bacterial sialadenitis with or without sialolithiasis, and nontuberculous mycobacterial (NTM) cervical adenitis—with NTM lymphadenitis being the most common form of NTM disease in children aged 1-5 years. 1

Infectious Causes

Lymphadenitis

• Bacterial lymphadenitis from infections of teeth, upper respiratory tract, sinuses, and tonsils is a leading cause of submandibular swelling 2
• Nontuberculous mycobacterial (NTM) lymphadenitis affects the submandibular, submaxillary, and cervical nodes, most commonly in children between 1-5 years old 1
• Approximately 80% of culture-proven NTM lymphadenitis cases are due to Mycobacterium avium complex (MAC) 1
• NTM lymphadenitis presents insidiously with unilateral (95%), non-tender nodes that may enlarge rapidly and rupture, forming sinus tracts with prolonged drainage 1
• Infectious mononucleosis and cat scratch disease can also cause submandibular lymphadenopathy 2

Viral Sialadenitis

• Mumps presents with swelling of one or more salivary glands, typically the parotid but can involve submandibular glands 3
• Up to one-third of mumps cases do not cause salivary gland swelling, presenting instead as respiratory tract infection 3
• The virus is isolated from saliva from 7 days before through 8 days after onset of salivary gland swelling 3

Bacterial Sialadenitis

• Acute bacterial sialadenitis can occur with or without salivary duct obstruction 4, 5
• Salivary stones (sialolithiasis) are most frequent in the submandibular gland, causing intermittent pain characteristically occurring just before eating 4
• Associated tenderness of the involved gland with slow or absent salivary flow from the duct 4

Congenital and Developmental Causes

Ductal Abnormalities

• Atresia of the submandibular duct orifice is a rare developmental anomaly causing swelling from saliva accumulation 6
• Can present with severe feeding difficulties and failure to thrive in infants 6
• Cystic mass in the floor of the mouth may interfere with feeding 6

Mucoceles

• Submandibular gland mucoceles are extremely rare but should be considered in young children with submandibular triangle swelling 7
• Result from extravasation or retention of mucous material from major or minor salivary glands 7
• Can present as serial swellings in the submandibular region 7

Autoimmune and Systemic Causes

• Sjögren syndrome can cause submandibular swelling 2
• Multiple systemic diseases can manifest in the submandibular glands 8
• Chronic recurrent juvenile sialadenitis is a recognized entity requiring specialized management 5

Neoplastic Causes

Benign and Malignant Tumors

• Tumors of the submandibular gland, though rare in children, must be considered 2
• Hodgkin's disease and non-Hodgkin's lymphomas can present as submandibular masses 2
• In adults over 40 years, metastatic disease is the greatest cause of asymmetric submandibular enlargement, but this is less common in children 2
• Due to rarity of salivary gland tumors in children, treatment in specialized centers with greater surgical experience is recommended 5

Vascular Malformations

• Congenital cystic or vascular malformations should be considered in the differential diagnosis 8
• These are part of the spectrum of congenital diseases affecting salivary glands in childhood 5

Diagnostic Approach

Initial Evaluation

• Ultrasound is useful in children for differentiating solid from cystic neck lesions and discriminating high-flow from low-flow vascular malformations 9
• Color-flow Doppler US helps characterize vascular flow in solid lesions 9
• US may suffice for evaluation of superficial infection 9

Advanced Imaging

• CT neck with IV contrast can be performed in children suspected of having malignancy or deep neck infection requiring surgery 9
• MRI of the neck is appropriate for suspected malignancy or deep neck abscess 9
• Ultrasound is best for investigating salivary gland diseases initially 4
• Bimanual palpation enables detection of salivary stones in the duct 4

Key Clinical Pitfalls

• Do not assume all submandibular swelling is benign lymphadenitis—NTM infection requires specific diagnosis and management distinct from typical bacterial infections 1
• Inspect the oral cavity in infants with feeding problems, as ductal atresia can be missed 6
• Distinguish tuberculous from NTM lymphadenitis, as treatment differs significantly 1
• Consider congenital etiologies in addition to infectious and malignant causes when evaluating pediatric neck masses 9
• Contrast-enhanced axial CT of NTM lymphadenitis typically shows asymmetric adenopathy with ring-enhancing masses involving fat and skin but with minimal inflammatory stranding 1