What Causes Dry Mouth (Xerostomia)?

Dry mouth (Xerostomia) is defined as “abnormal dryness of the mouth resulting from decreased secretion of saliva”.

The causes of dry mouth are varied, but some of the most common include:

Pharmaceutical Drugs

Over 400 different drugs list dry mouth as a side effect.

Search our comprehensive list of drugs that cause dry mouth.

Tobacco Products

It should come as no surprise that smoking damages oral tissues.

What you may not know already is that most of the damage comes from free radicals robbing healthy oral tissues of electrons and overwhelming naturally-produced antioxidants in saliva.

The lack of salivary antioxidants is a direct cause of Xerostomia (dry mouth). Consuming tobacco products both dries out oral tissues and slows the body’s natural healing/hydrating process.

Diseases & Medical Conditions

Xerostomia can be caused by Parkinson’s disease, HIV/AIDS, diabetes, rheumatoid arthritis, systemic lupus erythematosus, scleroderma, sarcoidosis, amyloidosis, hypothyroidism and a variety of other medical conditions.

Sjögren’s Syndrome is a fairly common chronic autoimmune disease that causes white blood cells attack the body’s moisture-producing glands; causing persistent dry mouth and dry eyes. Affecting approximately 4 million Americans, Sjögren’s Syndrome is a leading cause of Xerostomia and can lead to other more severe complications.

Medical Treatments

Chemotherapy, radiation therapy, oral surgery, bone marrow transplants, medicinal treatments, of course, and other medical treatments can cause or worsen Xerostomia.

Radiation is probably the most common treatment-related cause of dry mouth, due to the volume of oral cancer patients that receive radiation treatments to the head and neck areas. The glands that generate and secrete saliva are often damaged by exposure to radiation. The severity and duration of the Xerostomia are directly related to the severity of the radiation treatment itself. Generally, the greater the exposure to radiation, the longer the resulting dry mouth condition.

However, a recent study has found evidence that applying topical antioxidants prior to radiation treatment can decrease the damage caused by radiation and the resulting loss of saliva flow. With oral cancer on the rise, the use of antioxidants to mitigate the damage caused by radiation offers a small, but important, measure of relief to oral cancer patients.

Natural Causes

Xerostomia tends to afflict the elderly, as a result of medication and medical conditions, but there are other common & naturally-occurring problems that can occur with patients of any age.

Mouth-breathing during sleep, caused by obstructed nasal passages, is very likely to cause dry mouth. If this happens regularly, severe Xerostomia symptoms are likely to develop.

In fact, any physical condition that causes mouth-breathing is likely to contribute to problems with dry mouth; for example: chronic allergies, tonsil hypertrophy, nasal polyps, deviated nasal septum or constricted upper airways. The underlying problem is that breathing through your mouth regularly causes dry mouth, which becomes more severe over longer periods of time.

Even naturally-occurring dehydration, when persistent, can lead to chronic dry mouth.