What is Xerostomia?

Xerostomia is a medical term for the feeling of having a dry mouth due to a lower amount of saliva being produced. In some cases, people might feel like they have a dry mouth even if the amount of saliva in their mouth hasn’t actually decreased. This reduced flow of saliva could lead to complaints of dryness in the mouth, a burning sensation, trouble swallowing, and even changes in taste. Xerostomia is usually caused by certain medications, radiation therapy to the head and neck, or a condition known as Sjögren syndrome.

Regardless of what causes it, the main issue for patients is the discomfort of having a dry mouth. The goal of treatment is to help relieve these symptoms, but it is not always possible to completely cure the dryness. The first step in treatment involves teaching the patient how to manage their symptoms: this might include taking regular sips of water and avoiding tobacco use. Local treatments, like using artificial saliva, can also help. If these methods aren’t successful, medication is also an option – a drug called pilocarpine is commonly used in such cases.

What Causes Xerostomia?

Xerostomia, or dry mouth, can be caused by many things. However, it most commonly happens because of a side effect of certain medications, due to radiation therapy in the head and neck area, and because of a condition called Sjogren syndrome. A lot of different medications can affect the function of the salivary glands, leading to dry mouth. The chance of this happening can increase depending on the dosage and how many different medications are being taken. This could be why older people often complain about dry mouth, as they tend to take more medications and may have other health conditions.

There are several types of medication that are known to cause dry mouth, including, but not limited to:

Anticholinergic agents: these are medications like atropine, belladonna, and oxybutynin.
Antidepressant and antipsychotic agents: like citalopram, haloperidol, and phenelzine.
Diuretics: medications such as furosemide, chlorothiazide, and hydrochlorothiazide.
Antihypertensive agents: blood pressure medications such as captopril, lisinopril, and enalapril.
Sedative and anxiolytic agents: calming and anxiety medicines like alprazolam, diazepam, and triazolam.
Muscle relaxants: like tizanidine, cyclobenzaprine, and orphenadrine.
Pain relief agents: such as opioids and NSAIDs.
Antihistamines: medications for allergies, such as astemizole, loratadine, and brompheniramine.

Dry mouth can often develop in patients who have had radiation therapy for head and neck cancers. This is especially true if the major salivary glands are in the path of the radiation. The flow of saliva usually decreases by about 50% to 60% when a certain level of radiation has been applied in the first week, reaching its lowest point after two to three weeks. The reduction in saliva production depends on the amount of salivary gland tissue affected by the radiation and the dose of radiation received. Unfortunately, saliva production levels before the radiation therapy are often not regained.

Sjögren syndrome, a condition characterized by dry mouth and eyes, often leads to dry mouth. It causes damage to the salivary glands due to inflammation. This condition is more common in women over 40 years of age. In some people, Sjögren syndrome only affects the salivary glands and eyes. In others, it can also be associated with autoimmune or connective tissue diseases, such as rheumatoid arthritis.

Other potential reasons for dry mouth might include autoimmune system disorders such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), thyroid disease, and primary biliary cirrhosis (PBC), habits like mouth breathing, dehydration, poorly controlled diabetes, nerve damage from head or neck injury, end-stage kidney disease, graft versus host disease (a complication that can occur after a stem cell or bone marrow transplant), and HIV/AIDS.

Risk Factors and Frequency for Xerostomia

Xerostomia, or dry mouth, affects both men and women. In a 1996 study in Sweden, it was found that 21.3% of men and 27.3% of women experienced xerostomia. Surveys have revealed that the condition can affect between 0.9% and 64.8% of people, with most of these studies taking place in Scandinavia and involving people over the age of 50.

Interestingly, all patients who underwent radiation therapy for head and neck cancer, or were diagnosed with Sjogren syndrome, reported experiencing xerostomia. The occurrence of xerostomia is on the rise as our population ages. While age itself does not cause xerostomia, older people are more likely to have it as they generally take more medications and have a higher occurrence of associated medical conditions.

In a 1996 study in Sweden, 21.3% of men and 27.3% of women had xerostomia.
The prevalence of xerostomia varies greatly, with rates between 0.9% and 64.8% reported.
All patients receiving radiation for head and neck cancer, or diagnosed with Sjogren syndrome, have reported xerostomia.
The number of xerostomia cases is growing due to an aging population.
While age doesn’t directly cause xerostomia, older patients are more likely to experience it due to being on multiple medications and having more associated health conditions.

Signs and Symptoms of Xerostomia

People suffering from xerostomia, or dry mouth, usually report experiencing the following symptoms:

A feeling of having a dry mouth
Burning or soreness in the mouth
Changes to taste or loss of taste entirely
A need to drink water in order to swallow, often leading to the need to carry a water bottle at all times
Difficulty swallowing dry foods like crackers
Feeling like saliva is thicker than normal
Being very sensitive to acidic or spicy foods
Loss of appetite and weight loss

Additionally, a clinical examination might reveal:

A cracked tongue and lips
Thinning of the filiform papillae (the small bumps on the tongue)
Red and dry mouth lining
The examiner’s finger sticking to the mouth lining during examination
Noticeable lack of saliva in the mouth

The reduced saliva production that characterizes xerostomia makes your mouth more likely to develop cavities, especially around the gum line, gum disease, bad breath, and mouth yeast infections. Denture users may find their dentures are uncomfortable and don’t fit as well. Xerostomia can be a symptom of Sjögren syndrome, and these patients might initially have complaints of dry eyes and swollen salivary glands before they notice oral symptoms.

Testing for Xerostomia

Xerostomia, or dry mouth, is a condition primarily diagnosed based on a patient’s symptoms and a physical examination. It’s believed that saliva production must be reduced by half before dry mouth becomes apparent. Thus, a patient’s report of feeling a dry mouth is often enough to both diagnose xerostomia and start treatment. It’s important to note that many medications can cause dry mouth, so doctors should always check a patient’s medication list.

If further checks are needed, several methods can be used to assess low saliva production, also known as hyposalivation. These methods include:

1. Sialometry: This test measures the salivary flow rate. The normal rate, when stimulated, is between 1.5 to 2.0 mL per minute, while the unstimulated rate ranges from 0.3 to 0.4 mL per minute. If the stimulated salivary flow is less than 0.5 to 0.7 mL per minute or unstimulated flow is under 0.1 mL per minute, a diagnosis of hyposalivation can be made.

2. Sialography: This is an imaging technique used to identify any stones or growths in the salivary glands. One particular method, three-dimensional (3D) MR sialography, seems promising especially in patients who have been exposed to radiation, as it can visualize saliva flow. A small trial has shown promising results where imaging was done at six weeks before radiation treatment and six months after treatment showed a decrease in saliva flow.

3. Biopsy: If a systemic cause like sarcoidosis, amyloidosis, or a salivary mass is suspected, a biopsy (where a small sample of tissue is taken for examination) of a salivary gland may be needed. The further course of action depends on the biopsy results.

In some cases, where xerostomia is a symptom of another disease like rheumatoid arthritis or lupus (known as secondary Sjögren syndrome), patients may show other signs and symptoms of an autoimmune disorder. Lab tests might show irregularities like a raised erythrocyte sedimentation rate (ESR, a test that indirectly measures inflammation in the body), anemia, leukopenia (low white blood cell count), and the presence of certain immune molecules or autoantibodies. A lip biopsy, in this case, usually shows the presence of lymphocytes (a type of white blood cell) in the minor salivary glands.

Treatment Options for Xerostomia

The primary purpose of managing dry mouth, or xerostomia, is to alleviate symptoms. Where possible, we aim to address the underlying cause of the condition, such as treating a stuffy nose to prevent breathing through the mouth. If a specific medication is causing dry mouth, it’s worth considering discontinuing its usage or switching to another drug with lesser dry mouth side effects. The first step in treating dry mouth is to educate the patient about lifestyle habits that could reduce symptoms, and employing local treatments. If these tactics don’t provide relief, we may then explore prescription medications.

Patient Education

We advise that patients regularly sip on water, chew on sugar-free gum, suck on sugar-free candy, avoid caffeine, tobacco, alcohol, and gritty or tough-to-chew foods. Hydrating properly and maintaining good oral hygiene and dental care is also essential in managing dry mouth.

Local Measures

Artificial saliva in forms such as sprays, lozenges, and gels could be used before meals and as needed. Although these products don’t work consistently, only last for a limited time, may have an unpleasant taste, and might be costly, they can be useful at specific times, like during a flight or at bedtime.

Medication Treatment

Medications such as pilocarpine and cevimeline, which are FDA-approved for managing dry mouth, can stimulate the production of saliva. However, these drugs require some functional salivary gland to be effective as they incite the gland to produce saliva. Common side effects include sweating, nausea, and a runny nose.

Topical physostigmine, a chemical that increases the availability of a neurotransmitter called acetylcholine to stimulate salivary glands, can also be an option in treating dry mouth. A gel containing physostigmine may provide relief for about two hours.

Drugs like malic acid have been shown to be beneficial if the dry mouth is medication-induced. Anethole trithionate, which stimulates bile secretion, is another drug useful for dry mouth.

Other Measures

Electrical stimulation devices have shown to improve salivary flow, but they aren’t practical for everyday use. If you’re undergoing radiation therapy to your head and neck area, you might benefit from a drug called amifostine.

If you’re experiencing a dry mouth as your main symptom, the doctor might need to check for several conditions that are known to cause this. These could include:

Primary Sjögren syndrome, which is a disease that attacks the glands in your body
Idiopathic sicca syndrome, a condition where you have dry eyes and mouth but not because of a known cause
Autoimmune diseases, which occur when the body’s natural defense against infection instead attacks healthy tissue
Drug-induced sicca syndrome, which can happen as a side effect of certain medications

The doctor may also need to rule out other conditions which would require a specific treatment approach. These could include:

Sarcoidosis, a condition that causes small patches of red and swollen tissue to develop in the organs
Granulomatosis with polyangiitis, a rare disease affecting small and medium-sized blood vessels
IgG4-related disease, a newly recognized fibroinflammatory condition
Chronic Hepatitis C or HIV, both of which are viral infections
GVHD (Graft versus host disease), a complication that can occur after certain types of transplants
ESRD (End-stage renal disease), the last stage of chronic kidney disease
Head and neck radiation therapy, which can cause dry mouth as a side effect

What to expect with Xerostomia

The outlook for dry mouth depends on what’s causing it. Almost all patients will see improvements with treatments that ease their symptoms. Doctors can often treat temporary causes of dry mouth, like dehydration, side effects from medication, and consumption of caffeine, tobacco, and alcohol, with good results.

However, if dry mouth is caused by long-term or irreversible conditions like Sjögren syndrome (an immune system disorder that affects glands that produce moisture) or damage from radiation therapy for head and neck cancer, the symptoms tend to persist. In these cases, the treatment focuses on relieving symptoms as much as possible.

Possible Complications When Diagnosed with Xerostomia

Saliva plays a crucial role in our mouth. It keeps our mouth moist and clean, protects it from physical harm, and helps start the digestion process. It even guards us from microbial infections thanks to proteins and antibodies in it. So, when individuals have a dry mouth, or “xerostomia,” they can experience a series of negative effects. Dry mouth might lead to difficulties in eating which can cause poor nutrition. It can also result in gum diseases like gingivitis and periodontitis, tooth decay, bad breath, fungal infections like candidiasis, and speed up tooth erosion. Moreover, the chronic discomfort from having a dry mouth may also contribute to feelings of anxiety and depression.

Issues Resulting from Dry Mouth:

Poor nutrition
Gingivitis and periodontitis (gum disease)
Tooth decay
Bad breath
Fungal infections (such as candidiasis)
Accelerated tooth erosion
Symptoms of anxiety and depression

Preventing Xerostomia

It’s really important for patients to talk with their doctors if they are experiencing symptoms like a dry mouth or bad breath. Doctors can suggest some simple steps you can take to help prevent these symptoms from becoming a bigger problem. These may include:

Drinking water throughout the day
Chewing gum, ideally without sugar
Using a device that adds moisture to the air in your mouth (this is called a mouth humidifier)
Cutting down on alcohol, coffee, tobacco, drinks with a lot of sugar, and candy
Keeping dry or cracked areas of the mouth moisturized

In addition to these preventative measures, it’s also really important to take care of your oral health by seeing your dentist regularly, flossing regularly and using toothpaste with fluoride (this is a mineral that can help protect your teeth). Taking these steps can help improve not just your oral health, but also your mental health, by reducing stress and depression. This way, you can lead a better quality of life.