We speak of hyposialia when the production of saliva decreases. The problem is not trivial since it can have a significant impact on the quality of life: feeling of dry mouth and permanent thirst, difficulty speaking or absorbing food, oral problems, etc. In addition, although it is not always the case, it can be indicative of another disease, such as diabetes.

Hyposialia is not necessarily pathological. It can occur during an episode of dehydration for example, and disappear as soon as the body is hydrated again.

But, in some people, hyposialia is permanent. Even when they are not exposed to heat and drink lots of water, they still feel like they have a dry mouth. This sensation, also called xerostomia, is more or less strong. And it is objective: there is a real lack of saliva. 

Note that having a feeling of dry mouth is not always linked to low saliva production. Xerostomia without hyposialia is a frequent symptom of stress in particular, which subsides with it.

Hyposialia is observed in the following situations:

• an episode of dehydration : dry mouth is then accompanied by dry and cracked lips, with a very increased sensation of thirst;
• medication : many substances can have an impact on the activity of the salivary glands. These include, for example, antihistamines, anxiolytics, antidepressants, neuroleptics, diuretics, certain analgesics, antiparkinson drugs, anticholinergics, antispasmodics, antihypertensives or even chemotherapy;
• aging : with age, the salivary glands are less productive. Medication doesn’t help. And the problem is even more marked during a heat wave, because the elderly feel less thirsty, even when their body lacks water;
• radiation therapy to the head and / or neck can affect the salivary glands;
• removal of one or more salivary glands, due to tumor for example. Normally, saliva is produced by three pairs of main salivary glands (parotid, submandibular and sublingual) and by accessory salivary glands distributed throughout the oral mucosa. If some are removed, the others continue to secrete saliva, but never as much as before;
• blockage of a salivary duct by a lithiasis (accumulation of minerals forming a stone), a stenosing disease (which narrows the lumen of the canal) or a saliva plug can prevent the escape of saliva produced by one of the salivary glands. In this case, hyposialia is usually accompanied by inflammation of the gland, which becomes painful and swells to the point of deforming the cheek or neck. This does not go unnoticed. Likewise, parotitis of bacterial origin or linked to the mumps virus can interfere with the production of saliva;
• certain chronic diseasessymptoms, such as Gougerot-Sjögren syndrome (also called sicca syndrome), diabetes, HIV / AIDS, chronic kidney disease, or Alzheimer’s disease include hyposialia. Other pathologies can also affect the salivary system: tuberculosis, leprosy, sarcoidosis, etc.
  

To find the cause of a hyposialia, in particular to rule out the hypothesis of a serious underlying disease, the attending physician may have to prescribe various examinations: 

• saliva analysis;
• flow measurement;
• blood test;
•  ultrasound of salivary glands, etc.

The first symptom of hyposialia is dry mouth, or xerostomia. But the lack of saliva can also have other repercussions:

• increased thirst : the mouth and / or throat are sticky and dry, the lips cracked and the tongue dry, sometimes unusually red. The person may also have a feeling of burning or irritation of the oral mucosa, especially when eating spicy food;
• difficulty speaking and eating Usually, saliva helps lubricate the mucous membranes, which helps chewing and swallowing. It participates in the diffusion of flavors, therefore in the perception of taste. And its enzymes initiate digestion by partly breaking down food. When it is not present in sufficient quantity to play these roles, patients have difficulty in articulating and lose their appetite;
• oral problems : in addition to its role in digestion, saliva also has a protective action against acidity, bacteria, viruses and fungi. Without it, teeth are more prone to cavities and demineralization. Mycoses (candidiasis type) settle more easily. Food debris accumulates between the teeth, since they are no longer “rinsed” by saliva, so that gum disease is favored (gingivitis, then periodontitis), as is bad breath (halitosis). Wearing a removable dental prosthesis is also less well tolerated.

In the event of an underlying pathology, its treatment will be given priority.

If the cause is drug, the doctor can investigate the possibility of stopping the treatment responsible for hyposialia and / or replacing it with another substance. If this is not possible, he or she may be able to reduce the prescribed doses or divide them into several daily doses instead of just one. 

The treatment of dry mouth itself is mainly aimed at facilitating eating and speech. In addition to hygiene and dietary recommendations (drink more, avoid coffee and tobacco, wash your teeth thoroughly and with a suitable toothpaste, visit the dentist every three to four months, etc.), saliva substitutes or oral lubricants may be prescribed. If they are not enough, drugs exist to stimulate the salivary glands, provided that they are still functional, but their side effects are not negligible: excessive sweating, abdominal pain, nausea, headaches, dizziness, etc. This is why they are not used very much.