The lumps you feel just below your jawbone on either side are mainly your submandibular salivary glands, a pair of walnut-sized organs whose job is to produce saliva. Scattered around and among them are also lymph nodes, small immune-system outposts that filter bacteria and viruses from nearby tissues. When something goes wrong with either structure, the area under your jaw swells, and the cause can range from a blocked salivary duct to an infection to something rarer like an autoimmune condition or a tumor.
What Actually Sits Under Your Jaw
Each submandibular gland sits in a small triangular pocket between the lower edge of your jawbone and the muscles of your neck. The gland drains saliva through a narrow tube called Wharton’s duct, which runs forward along the floor of your mouth and empties under your tongue. Because the duct is long and takes an upward path, the submandibular gland is especially prone to blockages, a design quirk that explains a lot of the swelling people experience in this area.
Alongside the glands sit several lymph nodes. These nodes receive drainage from the teeth, gums, tongue, and floor of the mouth, which is why a dental infection or a sore throat can make the area under your jaw feel puffy and tender even though the salivary gland itself is fine. Telling the two apart from the outside can be tricky, and even doctors sometimes need imaging to figure out which structure is actually enlarged.
Salivary Stones and That Painful Mealtime Swelling
One of the most common reasons a submandibular gland swells is a salivary stone, a hard mineral deposit that forms inside the gland or its duct and blocks the flow of saliva. The medical term is sialolithiasis, and it accounts for a large share of non-tumor-related submandibular problems. Stones form when calcium salts in saliva clump together, sometimes around bits of debris or thickened mucus. Because Wharton’s duct is relatively long and curves upward, it is the salivary duct most likely to develop a stone.
The hallmark symptom is swelling that gets worse when you eat or even think about eating. Chewing triggers a surge of saliva production, but with a stone blocking the exit, the saliva backs up and the gland balloons painfully. Between meals the swelling may partially subside, then flare again at dinner. If the blockage persists, bacteria can colonize the stagnant saliva and cause an abscess. One case report describes a patient who arrived with a week of worsening pain, swelling, fever, and difficulty swallowing, all traced back to a stone that had led to an abscess in the submandibular space.1PubMed Central. Submandibular abscess originated from submandibular gland sialolithiasis: a case report
Small stones sometimes pass on their own. Drinking plenty of water, sucking on sour candy to stimulate saliva flow, and gently massaging the gland can help nudge a small stone out. Larger or deeply lodged stones may need to be removed with a tiny scope threaded into the duct (sialoendoscopy) or, in stubborn cases, by surgically removing the gland itself.
Bacterial and Viral Infections
Infections are the other big category. Bacterial sialadenitis, an infection of the salivary gland, often starts when saliva flow slows down and bacteria from the mouth creep backward into the duct. The usual culprits are a mix of aerobic and anaerobic bacteria. Poor oral hygiene, diabetes, chronic dry mouth, and conditions that suppress the immune system all raise the risk.2Medicine and Materials. PREDISPOSING FACTORS AND ETIOLOGY OF SUBMANDIBULAR GLAND ABSCESS – Section: Abstract A duct already partially blocked by a stone is especially vulnerable because the stagnant saliva is a hospitable environment for microbes.
Symptoms of bacterial sialadenitis include a warm, tender, swollen area under the jaw, redness of the overlying skin, and sometimes pus draining from the duct opening under the tongue. Fever and general malaise are common. Treatment usually means antibiotics, hydration, warm compresses, and sialogogues (things that stimulate saliva flow). If an abscess forms, it may need to be drained.
On the viral side, mumps is the infection most strongly associated with salivary gland swelling, though it classically targets the parotid glands in front of the ears rather than the submandibular glands. Occasionally, though, the virus attacks only the submandibular gland while leaving the parotid alone, which can confuse the clinical picture. One documented case involved a patient with mumps limited to a single submandibular gland who went on to develop meningitis and orchitis as complications, showing that even an atypical presentation carries real risks.3PubMed. Complicated mumps viral infection: an unusual presentation affecting only submandibular gland Other viruses, including HIV, Epstein-Barr, and cytomegalovirus, can also cause salivary gland swelling, though these tend to involve the parotid glands more often.
Swollen Lymph Nodes Versus a Swollen Gland
Many people who notice a lump under their jaw assume it is a “swollen gland” without knowing whether the salivary gland or a lymph node is to blame. The distinction matters because the causes and treatments are different.
Lymph nodes under the jaw swell in response to infections in nearby tissues. A bad tooth, gum disease, a throat infection, or even a cold sore on the lip can trigger the nodes to enlarge as they ramp up immune activity. This kind of reactive swelling is usually tender, develops over a few days, and resolves once the underlying infection clears. The swollen node is typically mobile and somewhat rubbery to the touch. If you recently had a dental procedure, a sore throat, or a cut inside your mouth, a reactive lymph node is the most likely explanation.
A swollen submandibular salivary gland, by contrast, tends to feel larger and more diffuse, and its relationship to eating is a strong clue. If the swelling ramps up at mealtime, the gland itself is almost certainly involved. When there is no mealtime connection and no obvious infection nearby, the picture becomes murkier, and imaging usually helps sort things out.
Autoimmune and Inflammatory Conditions
Sometimes the immune system itself is the problem. Sjögren’s syndrome is an autoimmune disease in which the body’s immune cells attack moisture-producing glands, including the salivary and tear glands. The immune response destroys the gland’s working tissue over time, leading to chronic dry mouth, dry eyes, and recurrent salivary gland swelling.4PubMed Central. Outline of Salivary Gland Pathogenesis of Sjögren’s Syndrome and Current Therapeutic Approaches – Section: Abstract The parotid glands are the most visibly affected, but the submandibular glands frequently swell as well. Sjögren’s affects mostly women, typically surfaces in middle age, and is often associated with other autoimmune diseases like rheumatoid arthritis or lupus.
A less well-known condition called IgG4-related disease can also cause the submandibular gland to enlarge. When it hits the salivary glands, the old clinical name is Küttner’s tumor, though it is not actually a tumor at all. It produces a firm, painless swelling that can easily be mistaken for cancer.5PubMed. Kuttner tumor (chronic sclerosing sialadenitis) Because the lump feels hard and grows slowly, clinicians often suspect a malignancy. The correct diagnosis is usually made only after the gland has been surgically removed and examined under a microscope, which reveals dense scar-like tissue and clusters of immune cells rather than cancer.6PubMed Central. Küttner’s tumour: an unusual cause of salivary gland enlargement – Section: Abstract Because these three conditions — Sjögren’s, IgG4-related disease, and chronic duct obstruction — can all produce a swollen, firm submandibular gland, distinguishing them requires tissue analysis looking at distinct patterns of inflammation and scarring.7PubMed. Differential diagnosis of IgG4-related sialadenitis, primary Sjögren syndrome, and chronic obstructive submandibular sialadenitis
Sarcoidosis is another systemic inflammatory disease that occasionally targets the submandibular gland. A systematic review found only about 20 reported cases in the medical literature, almost all in women, and in some patients the submandibular swelling was the first and only sign of the disease.8PubMed. Sarcoidosis of the submandibular gland: A systematic review – Section: RESULTS That rarity is worth knowing: if your doctor is puzzling over a persistent submandibular lump, sarcoidosis is on the long list of possibilities but far from the top.
Tumors of the Submandibular Gland
Tumors in the submandibular gland are uncommon, but they carry a higher proportion of malignancy compared to tumors in the larger parotid gland. A review of cases over ten years found that the majority of submandibular tumors were benign, with pleomorphic adenoma being the single most frequent type.9Acta Otorrinolaringologica (English Edition). Histology of Submandibular Gland Tumours, 10 Years’ Experience – Section: Results Among the malignant tumors, adenocarcinoma and adenoid cystic carcinoma were the most common types.10Journal of Oral and Maxillofacial Surgery. Tumors of the submandibular gland: Clinicopathologic analysis of 23 patients – Section: Results
What makes submandibular tumors a clinical headache is their presentation. A benign pleomorphic adenoma usually feels like a firm, slow-growing, painless lump, and that description also fits a malignant tumor and the IgG4-related condition described above. Pain is not a reliable way to tell benign from malignant; many cancers are painless early on. The patient’s age can be a rough guide. In one series, the average age of patients with benign tumors was about 40, while malignant cases averaged around 55.9Acta Otorrinolaringologica (English Edition). Histology of Submandibular Gland Tumours, 10 Years’ Experience – Section: Results But individual cases vary widely, so a painless lump at any age warrants investigation.
A separate 15-year surgical series found that among submandibular gland tumors specifically, a striking 42% turned out to be malignant.11PubMed. Submandibular gland excision: 15 years of experience – Section: RESULTS That rate is substantially higher than what is seen in parotid tumors, where the large majority are benign. The practical takeaway is that any persistent, painless lump under the jaw that does not respond to antibiotics and does not come and go with meals should be evaluated sooner rather than later.
Medications That Can Cause Swelling
Certain drugs can make the submandibular glands swell even in the absence of infection, stones, or autoimmune disease. The psychiatric medication clozapine is one well-documented example. In some patients, clozapine’s effects on the glandular tissue cause saliva to thicken and stagnate. Calcium salts can then precipitate in the duct, effectively creating a drug-induced stone and subsequent gland distension.12Journal of Orofacial Sciences. Adverse affects of drugs on saliva and salivary glands – Section: DRUG INDUCED SIALADENITIS Other medications that reduce saliva production, including some antihistamines, antidepressants, and diuretics, can theoretically contribute to gland problems by allowing the same kind of stasis. If you notice new jaw swelling after starting a medication, it is worth mentioning to your doctor, since the solution may be as simple as switching drugs or adding measures to keep saliva flowing.
How Doctors Figure Out the Cause
A physical exam is the starting point: is the lump tender or painless? Does it change with meals? Is it in one gland or both? Are there other symptoms like dry eyes, weight loss, or fever? These details narrow the list considerably. But imaging is often needed to confirm the diagnosis.
Ultrasound is usually the first imaging test ordered because it is quick, painless, and good at showing whether a lump is solid or cystic, and at picking up salivary stones. For evaluating tumors specifically, ultrasound performed well in one comparative study, with higher sensitivity for detecting malignancy than CT scanning.13PubMed. Diagnosis of submandibular gland tumors: a comparison of CT and ultrasound CT has its own strengths, particularly for stones. In a study of submandibular stone patients who underwent both CT and ultrasound before confirmatory endoscopy, CT caught stones that ultrasound missed, while a handful of stones visible on ultrasound were obscured on CT by artifacts from dental fillings.14PubMed. Comparison of the Inadequacies of Ultrasonography and Computed Tomography in the Diagnosis of Sialolithiasis In practice, doctors sometimes use both modalities because each has blind spots that the other fills.
MRI is reserved for situations where the soft-tissue detail matters most, like distinguishing a deep tumor from surrounding muscles. Fine-needle aspiration, where a thin needle draws cells from the lump for microscopic examination, is commonly used when a tumor is suspected. And as noted in the section on IgG4-related disease, sometimes the definitive diagnosis only comes after the gland is removed and a pathologist examines the whole specimen.
When Children Get Jaw Swelling
Children develop swollen submandibular glands for many of the same reasons adults do, but the relative frequency is different. Reactive lymph node swelling from viral upper respiratory infections is by far the most common cause in kids. Salivary stones are rare in children, though not unheard of. Salivary gland diseases in children are often grouped with adult conditions in textbooks, but they can differ in how common each cause is and how the symptoms present.15PubMed Central. Salivary gland diseases in children – Section: Abstract
One important scenario to be aware of is autoimmune disease presenting unusually early. In a reported case, a child had recurrent submandibular gland swelling for over two years before being diagnosed with primary Sjögren’s syndrome. The child did not have the classic dry-mouth and dry-eye complaints that typically raise suspicion in adults, which delayed the diagnosis until blood tests and a biopsy pointed to the answer.16Journal of Craniofacial Surgery. Recurrent Submandibular Gland Swelling as a First Manifestation in a Child With Primary Sjögren Syndrome – Section: Abstract The lesson is that if a child has repeated episodes of submandibular swelling without an obvious infectious cause, it is worth investigating beyond “just another swollen gland.”
What Happens When the Gland Needs to Come Out
Submandibular gland removal (submandibulectomy) is a well-established surgery performed for recurrent stones that cannot be managed less invasively, chronic infections, and tumors. The procedure involves an incision in the upper neck, and recovery generally takes a week or two. Losing one submandibular gland does not cause a noticeable drop in saliva production because the remaining salivary glands compensate.
The main risk is nerve injury. Several important nerves run close to the gland. The marginal mandibular branch of the facial nerve controls the muscles around the corner of your mouth; damage to it can cause the lower lip to droop on the affected side. In one series of 45 operations, temporary weakness of this nerve occurred in about 16% of patients, while permanent damage occurred in one case.17PubMed Central. Submandibular Gland Surgery: Our Clinical Experience – Section: Results A larger series over 15 years reported lower rates of transient facial nerve palsy (about 9%) and lingual nerve problems (about 2%), with permanent damage in under 1% of patients.11PubMed. Submandibular gland excision: 15 years of experience – Section: RESULTS The lingual nerve, which provides sensation to one side of the tongue, and the hypoglossal nerve, which controls tongue movement, are also at risk but less commonly affected. Overall, serious permanent complications are unusual, though the possibility of temporary lip weakness is something surgeons routinely discuss before the procedure.
When to Worry and When to Wait
Most episodes of jaw swelling are benign and self-limiting. A reactive lymph node from a cold or a minor dental issue will shrink on its own in a week or two. A small salivary stone that produces intermittent mealtime swelling may pass with conservative measures. But certain features should prompt a faster trip to a healthcare provider:
- Persistent painless lump: A firm mass that does not fluctuate with meals and has been present for weeks may be a tumor or an inflammatory condition that needs biopsy.
- Rapid growth with fever: This pattern suggests an abscess forming, which may need drainage and antibiotics.
- Bilateral swelling with dry mouth and dry eyes: This combination raises suspicion for Sjögren’s syndrome and warrants blood tests.
- Swelling after starting a new medication: Drug-induced gland enlargement is treatable once recognized.
- Recurrent episodes in a child: Repeated swelling without a clear infectious cause deserves a closer look for stones or early autoimmune disease.
The under-jaw area packs a lot of anatomy into a small space, and the same symptom, a visible or palpable swelling, can point to dozens of different conditions. That overlap is why clinicians lean heavily on imaging and sometimes tissue sampling rather than trying to diagnose by feel alone. For most people, the story ends with a reactive lymph node or a manageable stone. But knowing the range of possibilities helps you have a more productive conversation with your doctor if the swelling does not go away on its own.