Dry mouth, or xerostomia, is the subjective sensation of oral dryness. It is most often caused by a measurable reduction in the production of saliva from the salivary glands, a condition called hyposalivation. Saliva is the unsung hero of our oral health. Far from being just water, it is a complex fluid that works around the clock to perform hundreds of vital functions.

To fully grasp the impact of dry mouth, it is essential to appreciate the critical roles that saliva plays every minute of the day:

• Lubrication and Speech: Saliva moistens the soft tissues of the mouth, allowing us to speak clearly and comfortably without our tongue sticking to our palate or teeth.
• Digestion: It moistens food to help with chewing and swallowing, and it contains enzymes, like amylase, that begin the process of breaking down carbohydrates.
• Taste: Saliva dissolves food particles, which is necessary for our taste buds to properly perceive flavors.
• Acid Neutralization: After we eat, bacteria in our mouth produce acids that attack our tooth enamel. Saliva is slightly alkaline and acts as a powerful buffer, neutralizing these acids and protecting our teeth from decay.
• Cleansing: It constantly washes away food debris and bacteria from the surfaces of our teeth and gums.
• Antibacterial Action: Saliva contains proteins and enzymes that have antibacterial, antifungal, and antiviral properties, helping to control the population of harmful germs in the mouth.

In my experience, patients often describe it as a constant feeling of thirst, difficulty swallowing, or waking up with a sticky mouth, dry mouth is more than just being dehydrated.

Xerostomia results from any factor that reduces the quantity or changes the quality of the saliva produced by the major and minor salivary glands. The list of potential causes is extensive.

Side Effects of Medications

This is, by a significant margin, the single most common cause of chronic dry mouth. The risk increases dramatically with polypharmacy, the use of multiple medications at once. Common culprits include:

• Antihistamines and Decongestants: Used for allergies and colds.
• Antidepressants, Anti-anxiety Medications, and Antipsychotics.
• Blood Pressure Medications: Particularly diuretics (“water pills”) and beta-blockers.
• Pain Medications: Including both opioids and nonsteroidal anti-inflammatory drugs (NSAIDs).
• Sedatives and Muscle Relaxants.
• Medications for an Overactive Bladder.

Medical Conditions and Diseases

A number of systemic diseases can damage the salivary glands or affect the nerve signals that control them.

• Sjögren’s Syndrome: An autoimmune disease where the body’s immune system mistakenly attacks its own moisture-producing glands, primarily the salivary and lacrimal (tear) glands, leading to profound dry mouth and dry eyes.
• Other Autoimmune Diseases: Rheumatoid arthritis and lupus can also be associated with dry mouth.
• Diabetes Mellitus: Poorly controlled diabetes can cause dehydration and contribute to dry mouth.
• HIV/AIDS.
• Alzheimer’s Disease.

Medical Treatments

• Radiation Therapy: Radiation delivered to the head and neck for cancer treatment can cause severe and often permanent damage to the salivary glands located in the radiation field.
• Chemotherapy: Certain chemotherapy drugs can temporarily reduce saliva production and make saliva thick and stringy.

Nerve Damage

An injury, trauma, or surgery involving the head or neck can damage the nerves that are responsible for signaling the salivary glands to produce saliva.

Lifestyle Factors

• Dehydration: Not drinking enough fluids from any cause (e.g., heat, exercise, fever, vomiting, or diarrhea).
• Mouth Breathing: Chronic mouth breathing, especially at night due to nasal congestion, dries out the oral tissues.
• Smoking or Chewing Tobacco.
• Alcohol and Caffeine: Both can have a diuretic effect and contribute to dehydration.

Clinically, the most common causes I’ve seen include medications (like antihistamines, antidepressants, or blood pressure meds), radiation therapy to the head and neck, and autoimmune diseases like Sjögren’s syndrome.

A person develops dry mouth as a symptom or side effect of one of the many causes listed above. It is not something you can catch from another person. The primary risk factors are those that predispose you to these underlying conditions or treatments.

The most common risk factors for developing chronic dry mouth are:

• Taking multiple medications (polypharmacy).
• Being an older adult, as older individuals are more likely to have chronic diseases and be on multiple medications.
• Undergoing cancer treatment, particularly radiation to the head and neck.
• Having a diagnosed autoimmune disease like Sjögren’s syndrome or rheumatoid arthritis.
• Living with poorly controlled diabetes.

Patients are often surprised to learn how many common drugs contribute to dry mouth, polypharmacy in older adults is a major factor I encounter frequently.

The experience of xerostomia goes far beyond just feeling thirsty. The lack of saliva creates a wide range of uncomfortable and problematic symptoms.

The most common signs and symptoms include:

• A frequent feeling of dryness, stickiness, or cottonmouth.
• Saliva that feels thick, stringy, or foamy.
• Difficulty speaking (dysarthria), as the tongue sticks to the roof of the mouth.
• Difficulty chewing and swallowing (dysphagia), especially dry foods like crackers or bread.
• A diminished or altered sense of taste (dysgeusia).
• A persistent sore throat or a burning sensation in the mouth, particularly on the tongue.
• A dry, red, or cracked tongue.
• Cracked lips and sores or splits at the corners of the mouth (angular cheilitis).
• A frequent need to sip liquids to help with talking or eating.

Oral Health Complications

One of the most serious and destructive consequences of chronic dry mouth is its devastating effect on oral health. This is a critical public health message. Without the protective benefits of saliva, the risk of dental problems increases dramatically.

• Rampant Tooth Decay (Dental Caries): Without saliva to wash away food debris and neutralize acid, the teeth are under constant attack. This often leads to aggressive decay, characteristically appearing at the gumline and around the necks of the teeth.
• Gingivitis and Periodontal (Gum) Disease.
• Oral Infections: A dry mouth is a more hospitable environment for the overgrowth of fungus, leading to oral candidiasis (thrush).
• Difficulty with Dentures: A lack of saliva can make it difficult for dentures to stay in place and can cause significant chafing and sores on the gums.

Clinically, I check for tongue fissuring, lack of saliva pooling, and dental enamel changes, these subtle signs often confirm xerostomia even when the patient isn’t fully aware.

A diagnosis of dry mouth is often made by a dentist or a physician based on a patient’s symptoms and a careful examination of the mouth.

• Medical and Medication History: A thorough review of a patient’s medical conditions and a complete list of all their medications (both prescription and over-the-counter) is the single most important first step in identifying the likely cause.
• Oral Examination: A doctor or dentist will examine the mouth and will often see the classic signs of hyposalivation: a lack of pooled saliva under the tongue, a dry or fissured appearance of the tongue, and saliva that is thick or stringy. They will also look for the complications, such as tooth decay or signs of a yeast infection.
• Sialometry: In some cases, a specialist may perform a test to objectively measure salivary flow. This involves having the patient spit all the saliva they produce into a tube over a period of several minutes. A very low volume confirms hyposalivation.
• Further Testing for Underlying Causes: If an autoimmune disease like Sjögren’s syndrome is suspected, a doctor will order specific blood tests to look for autoantibodies. In some cases, a biopsy of a minor salivary gland from the inside of the lip may be performed.

Clinically, I base the diagnosis largely on symptoms and oral exam but in autoimmune-related cases, I also run antibody tests and may refer for salivary gland imaging or biopsy.

There is no single cure for most causes of chronic dry mouth. Treatment is focused on three main goals: managing the underlying cause if possible, relieving the symptoms of dryness, and, most importantly, preventing the oral health complications.

1. Addressing the Underlying Cause

If the dry mouth is caused by a medication, a doctor may be able to switch to a different drug that has fewer drying side effects. If it is caused by a medical condition like diabetes, improving control of that condition can help. For autoimmune diseases, treatment is directed at the underlying disease.

2. Lifestyle and Home Care

This is the foundation of managing dry mouth symptoms and is accessible to everyone.

• Stay Hydrated: Sip water or other sugar-free drinks frequently throughout the day.
• Stimulate Saliva Flow: Chewing sugar-free gum or sucking on sugar-free hard candies can stimulate the salivary glands to produce more saliva. Products containing xylitol are particularly recommended as xylitol has anti-cavity properties.
• Moisturize the Mouth: Use over-the-counter saliva substitutes. These products come in the form of sprays, gels, and rinses and can provide temporary lubrication and comfort.
• Moisten Food: Use broths, gravies, or sauces to moisten food and make it easier to swallow.
• Use a Humidifier: Running a cool-mist humidifier at night can help with mouth breathing and nocturnal dryness.
• Avoid Irritants:
  • Limit caffeine and alcohol.
  • Avoid smoking or using tobacco products.
  • Avoid using mouthwashes that contain alcohol, as they can be very drying.
  • Avoid dry, salty, or overly spicy foods that can irritate the oral tissues.

3. Meticulous Oral Hygiene

This is absolutely critical to prevent the devastating dental complications of dry mouth.

• Brush your teeth gently with a fluoride toothpaste after every meal and before bedtime.
• Floss your teeth daily.
• Visit your dentist for check-ups and cleanings more frequently, often every three to six months.
• Your dentist may recommend a prescription-strength fluoride toothpaste or a daily fluoride rinse to provide extra protection against decay.

4. Prescription Medications

For individuals with severe dry mouth due to conditions like Sjögren’s syndrome or radiation damage, a doctor may prescribe medications called sialogogues, which stimulate the salivary glands to produce more saliva. The two most common drugs are pilocarpine and cevimeline.

Clinically, I focus on treating the cause whether it’s switching medications, managing diabetes better, or addressing an autoimmune disease and preventing dental complications.

Dry mouth, or xerostomia, is more than just a nuisance. It is a common and often distressing condition, most frequently caused by the side effects of medications, that can lead to significant discomfort and a high risk of severe dental disease. While the underlying cause cannot always be changed, the symptoms and risks are highly manageable. A proactive approach, centered on diligent home care strategies like sipping water and stimulating saliva flow, combined with an unwavering commitment to meticulous oral hygiene and regular dental visits, can provide significant relief. In my experience, dry mouth is more than an annoyance, it can affect nutrition, speech, and oral health, so early recognition and intervention really matter.

National Institute of Dental and Craniofacial Research (NIDCR), NIH. (2023). Dry Mouth. Retrieved from https://www.nidcr.nih.gov/health-info/dry-mouth

American Dental Association (ADA). (n.d.). Dry Mouth. Retrieved from https://www.mouthhealthy.org/en/az-topics/d/dry-mouth

Sjögren’s Foundation. (n.d.). Dry Mouth. Retrieved from https://sjogrens.org/understanding-sjogrens/symptoms/dry-mouth