The area under my jaw swells when I eat: is it a salivary stone?

The salivary gland under the jaw (the submandibular gland) is a gland about the size of a walnut that sits on the inner side of the jawbone, just above its lower edge. The saliva it makes is carried by a thin duct (Wharton's duct) to a small opening under the tongue, behind the front teeth. At rest the gland produces little; when food is seen or smelled, and especially when something sour enters the mouth, the flow increases markedly.

If there is a stone in the duct, the problem shows itself with this increase. MSD Manuals writes that blocking stones cause swelling and pain in the gland, particularly after eating, which stimulates the flow. The NHS, too, explains that with a complete blockage the pain comes while eating and lasts an hour or two. With a partial blockage, saliva trickles out slowly and the swelling goes down; this is why the complaint comes and goes, and at some meals does not happen at all. Some stones cause no symptoms at all and are found by chance on an X-ray taken for another reason.

Why stones form here most often is also known. MSD Manuals states that about 80% of stones form in the gland under the jaw, most of the rest in the gland in front of the ear (the parotid), and 1% in the gland under the tongue, and that about a quarter of patients have more than one stone. Stones are mostly made of calcium phosphate and settle out where the saliva becomes stagnant. The same source describes stagnant saliva in people who are frail, dehydrated, eating little or taking medicines that reduce saliva (anticholinergics); it adds that persistent or recurring stones make the gland prone to infection. The NHS, for its part, writes that the cause of the stones is not fully known, and that there is therefore no sure way to prevent them.

You can try a simple test at home to make this cycle clearer. On an empty stomach, when there is no swelling, compare both sides under your jaw with a mirror and your fingers. Then suck a slice of lemon or a sugar-free sour sweet and watch the side that swells over the next few minutes. A blocked gland often responds to this stimulus quickly, with tightness and fullness. Over the same day, note several meals, the minute the swelling starts and how long it takes to go down. This record does not make a diagnosis, but it is the most valuable information you can take to the doctor. If the swelling does not change at all with food, the picture on this page does not fit you; look at how the other swellings under the jaw are told apart.

Where the stone sits determines both the symptoms and the treatment. Stones at the end of the duct near its opening in the mouth can sometimes be seen, or felt by hand, as a hard spot under the tongue; MSD Manuals writes that a stone can sometimes be felt by examining the floor of the mouth with two hands. Stones where the gland opens into the duct (the hilum), or inside the gland itself, tend to be larger and cannot be seen from inside the mouth. In a Korean study that reviewed 428 operations, stones inside the gland and at the hilum were significantly larger than those in the front and middle parts of the duct.

There is a subtlety you need to know about imaging: ultrasound is the first choice, but it does not see every stone. MSD Manuals writes that the sensitivity of ultrasound varies between 60% and 95% depending on the study. In a series of 68 patients in Philadelphia confirmed by endoscopy, in the 48 patients who had an ultrasound it showed 65% of the stones and CT showed 98%, and most of the stones ultrasound missed were at the front end of the duct. So if the swelling with food is clear but the ultrasound came back clear, this may not mean there is no stone. According to the same source, 90% of stones under the jaw show up on an X-ray, while 90% of parotid stones do not.

If a blocked gland cannot empty for a long time, it can become infected. The NHS lists pain, redness or pus around the stone, and a high temperature, as signs of infection. MSD Manuals describes bacterial inflammation of a salivary gland as fever, chills, pain and swelling on one side, a firm and tender gland, redness of the skin over it, and pus coming from the duct opening when the gland is massaged; it writes that this picture is seen especially in people with a dry mouth, dehydration or a chronic illness, and that if an abscess develops it needs to be drained.

There is also a picture that is not the subject of this page but must not be confused with it: an infection spreading from a tooth. An infection that starts in the lower back teeth can also make the area under the jaw swell, but it does not come and go with food; it causes a constant swelling that grows and becomes harder. With a dental abscess, the NHS lists difficulty breathing, speaking or swallowing, a lot of swelling in the mouth, difficulty opening the mouth, swelling or pain in the eye and sudden problems with sight among the reasons to call 999 or go to A&E; in Turkey that means 112.

The first list has measures that can be tried at home for a few days. If a single item from the second list applies to you, stop waiting at home.

This complaint falls to an ear, nose and throat specialist or an oral and maxillofacial surgeon. Your dentist can do the first examination, see the stone on an X-ray and refer you.

1. 1

   Emergency signs are ruled out first

   If there is difficulty breathing, speaking or swallowing, hardness in the floor of the mouth or a high temperature, the assessment is done in A&E.

2. 2

   You are asked about the link with food

   At which meal the swelling starts, how long it takes to go down, how often it comes back and whether you have ever passed a stone are discussed. Show the notes you have kept and any photos you took while it was swollen.

3. 3

   The floor of the mouth is examined with two hands

   One hand inside the mouth under the tongue, the other outside under the jaw. Stones in the front part of the duct can often be felt this way; when the gland is massaged, the doctor looks at whether the saliva coming from the duct opening is clear, cloudy or contains pus.

4. 4

   Imaging

   It usually starts with an ultrasound. If the ultrasound is clear but the complaint continues, a CT or MRI scan is requested; ultrasound is known to be able to miss stones, particularly at the front end of the duct.

5. 5

   The size and position of the stone are measured

   These are the two facts that decide the treatment. Stones near the opening in the mouth are removed through a small cut inside the mouth, small stones inside the duct by endoscope, and large stones inside the gland by other methods.

6. 6

   Treatment and follow-up

   If there is an infection, antibiotics and fluids first, then removal of the stone. After the procedure, a check is made on whether the complaint comes back.

The options below are not rivals; where the stone sits and how large it is decide which one is suitable. Today, the aim is to preserve the gland wherever possible.

The following are the decisions that most often cost time, or the gland, with this complaint.

The time depends on the size of the stone and the method chosen; the sequence below is a general framework.

1. The first days of measures at home

   Small, mobile stones can come out within this time. When the stone comes out, the swelling and pain that come with food stop.

2. If the stone stays in place

   The swelling comes back at every meal. The NHS recommends seeing a doctor about a stone that does not pass on its own and is causing trouble.

3. After the stone is removed

   In the series of 43 patients, at an average follow-up of 24 months, 37 patients had no symptoms, 2 had mild symptoms of blockage that needed no treatment, and 4 had the gland removed because of repeated infections.

4. In the long term

   MSD Manuals states that about a quarter of patients have more than one stone, and that persistent or recurring stones make the gland prone to infection. The NHS writes that stones that have been removed do not usually come back, and that if they often do, the gland may need to be removed. If the same cycle returns, report it early.

We do not give a single figure here, because behind a gland that swells with food there may be a small stone that comes out at home, or a large stone that calls for removal of the gland. These are the items that determine the scope:

The position and size of the stone

A small stone at the duct opening and a large stone inside the gland are entirely different procedures.

Imaging

Ultrasound is often enough; if a missed stone is suspected, a CT or MRI scan is added.

The method chosen

Removal from inside the mouth, endoscopy, breaking up the stone and removal of the gland each need different equipment, anaesthesia and time.

Treatment of infection

If the gland has become infected, medicines and, if needed, draining an abscess are separate items.