What causes dry mouth and how to remedy it

Thirsty, parched, cotton-mouthed – we have plenty of words to describe the feeling of a dry mouth. That’s because dry mouth can be so common. For most people, a hearty chug of water does the trick to “wet your whistle.” But sometimes, no matter how much you drink, nothing quenches a dry mouth.

The feeling or sensation of a dry mouth, known as xerostomia, can be a perfectly normal reaction to dehydration or stress. But in some cases of chronic dry mouth, the body may not be making enough saliva, or something has altered saliva composition. Below, we’ll explore what causes dry mouth, how to remedy it and when to see a doctor for help.

Where saliva comes from and why it’s important

Saliva, commonly called spit, is a watery fluid that coats the mouth and keeps it moist. Although it’s 98% water, the other 2% of saliva is composed of electrolytes, enzymes, minerals, mucus, proteins and antibacterial compounds. Saliva is integral to oral health because it prevents tooth decay and gum disease, and helps break down food as we chew it, making it easier to swallow. It’s also important for our sense of taste and our ability to speak.

The majority of saliva comes from three pairs of salivary glands:

• Sublingual salivary glands at the bottom of the mouth
• Submandibular salivary glands under the jaw
• Parotid salivary glands in front of the ears

The saliva produced by these glands enters the mouth through branching tubes located under the skin called ducts. The production of saliva is controlled by the autonomic nervous system. This means it’s automatic – we don’t have to think about it. Nerves located in and around the face and mouth communicate with the salivary glands to make saliva when more is needed.

Saliva contributes to overall health

Because of its antimicrobial properties, saliva is an important part of the immune system. When your mouth is exposed to germs – from the food you eat or the air you breathe – your saliva acts as a barrier. It neutralizes these germs before they can enter the rest of your body and make you sick. At the same time, your saliva maintains a healthy, balanced microbiome of good bacteria in your mouth, helping to protect your teeth, gums and tongue from disease.

Side effects of persistent dry mouth

Having an occasional dry mouth is not a cause for concern beyond being a slight annoyance. If your mouth is consistently dry, however, you may start to notice the more severe and disruptive symptoms of xerostomia (dry mouth), like:

• Altered sense of taste
• Cracked lips and mouth corners
• Dry, textured tongue
• Hoarse voice or difficulty speaking
• Facial swelling
• Sore throat
• Thick, stringy saliva
• Trouble chewing and swallowing

When there’s not enough saliva in your mouth, unhealthy bacteria, viruses and fungus can gather and multiply, leading to:

• Bad breath
• A burning sensation in the mouth
• Cavities
• Gum disease
• Frequent mouth sores
• Thrush (a yeast infection in the mouth)

Causes of dry mouth

Xerostomia is often associated with hypofunction, which is when the salivary glands produce low saliva, or the glands are not working correctly to produce a normal flow or composition of saliva.

Prescription medication, smoking cigarettes and not drinking enough water are a few of the many causes of dry mouth. Sometimes, it can be the result of several factors.

Medication

Dry mouth is a common side effect of several over-the-counter and prescription medicines, including:

• Antihistamines
• Blood pressure medication, like diuretics
• Decongestants
• Medicines that treat anxiety and depression, especially tricyclic antidepressants
• Muscle relaxers
• Pain relievers
• Parkinson’s disease medications

Age

It’s common for older adults to experience frequent dry mouth. This is because, as we get older, we can become more susceptible to the side effects from various medications, including dry mouth side effects.

The elderly are also more prone to dehydration because they may not feel thirst as acutely. Plus, the level of sodium in the body decreases over time, and with lower sodium levels, the body doesn’t retain as much water.

Cancer treatment

Different types of cancer treatment can disrupt the natural balance of your mouth and cause side effects like dry mouth. For example, radiation therapy to the head and neck can destroy the cells that are responsible for producing saliva. Chemotherapy, immunotherapy or other medicinal therapies can dry out your mouth or alter the thickness of your saliva.

Talk to your cancer care team if you are experiencing dry mouth. Your doctor may prescribe or recommend mouthwashes, sprays or rinses to help alleviate discomfort and manage the side effects of the cancer treatment.

Injury, illness or infection

An injury to the head or neck area can damage the nerves that help the salivary glands function properly. Additionally, certain conditions that come with nasal congestion – like the common cold and flu or a deviated septum – can force you to breathe through your mouth. When this happens, the inhaled and exhaled air dries out the healthy coating of saliva in your mouth, resulting in a dry mouth.

When bacteria and viruses (including COVID-19) invade the salivary glands and surrounding ducts, the resulting inflammation is known as sialadenitis. Sialadenitis disrupts salivary gland function and may be accompanied by swelling, pain and fever.

Salivary stones, also known as sialoliths, can be another culprit of salivary gland swelling and, subsequently, dry mouth. Salivary stones form when the minerals contained within saliva harden and block salivary gland ducts, increasing the likelihood of sialadenitis. There are many possible causes of salivary stones, including inadequate water consumption, certain medications and tobacco smoking.

Chronic health conditions

Persistent dry mouth is a side effect of some chronic illnesses. These include:

• Asthma – People with asthma often feel as if they’re not getting enough air, causing them to mouth breathe to compensate. The medicine in inhalers can also dry out the mouth.
• HIV – The human immunodeficiency virus (HIV) can interfere with your salivary glands and their production of saliva, making it hard to keep your mouth adequately moist. Chronic dry mouth can be a common side effect of early HIV infection.
• Hepatitis C virus – Early infection with the hepatitis C virus can come with mild symptoms, or no symptoms at all. Symptoms become more noticeable once the infection becomes chronic. Dry mouth can be a symptom of chronic HCV if the hep C virus causes inflammation in the salivary glands.
• Sjogren’s syndrome – As an autoimmune disease, Sjogren’s syndrome involves the immune system attacking fluid-producing glands throughout the body, including the salivary glands. This hinders their ability to make adequate saliva.
• Diabetes – Hyperglycemia, or high blood sugar, can dry out the mouth, although doctors aren’t yet sure why. Managing your blood sugar levels can help you avoid this and other side effects of diabetes.
• Thyroid disease – Both hypothyroidism (underactive thyroid gland) and hyperthyroidism (overactive thyroid gland) can interfere with the body’s hormone balance. This can affect the salivary glands and lead to dry mouth.

Also, the problems with swallowing that many people experience after a stroke can cause dry mouth.

Dehydration

A dry mouth is one of the first signs that your body is becoming dehydrated. Remember that saliva is 98% water, and when you’re dehydrated, your body doesn’t have enough water to make as much saliva as you need. Be sure to drink water throughout the day to prevent dehydration, especially if you’re active or spending time in hot weather.

Alcohol, tobacco and drug use

Drinking alcohol and using tobacco or other recreational drugs, like marijuana, can cause or exacerbate dry mouth and worsen any oral health problems. If you’re suffering from dry mouth, avoid alcohol, tobacco and marijuana.

In some cases, relieving a dry mouth is as simple as making a few lifestyle changes.

Drink enough water each day

Avoid dehydration and prevent dry mouth by drinking water throughout the day. According to the U.S. National Academies of Sciences, Engineering, and Medicine, men need 3.7 liters of water and women need 2.7 liters each day to stay adequately hydrated. But that number can change based on your individual activity level and how much you sweat.

Spray water into your mouth

Those experiencing salivary hypofunction (inadequate saliva production or dysfunctional salivary glands) may want to swish with water or use a small spray bottle or atomizer to spray water in their mouths. This lets you moisten the oral tissue without swallowing what saliva you may have.

Try to breathe through your nose, not your mouth

Make a concerted effort to breathe mostly through your nose, especially at night, to avoid drying out your mouth. Breathing through your nose at night means you won’t wake up with a mouth that is bone dry, and you might find that you’re more well rested. This can be tricky to do during sleep if you’re accustomed to mouth breathing. So try elevating your head with a pillow, positioning yourself on your side in bed, and ensuring nothing is blocking your sinuses or nasal passages.

If breathing through your nose seems difficult or impossible, you may have a deviated septum. Your primary care provider can help diagnose your breathing challenges, and refer you for specialized ear, nose and throat (ENT) treatment, if needed.

Use a humidifier in your home

Dry air can make for a dry mouth. Keep the air in your home, especially your bedroom, at a comfortable moisture level – around 30-50% humidity – with a humidifier. Place the humidifier on the nightstand, ideally, or other spots close to where you sleep.

Massage the salivary glands

Using massage techniques on the salivary glands can increase the flow of saliva naturally. With two fingers, apply gentle pressure starting at the lower front of the ear and sliding along the cheek, just under the cheekbone. Do the same directly under the jawbone, moving fingers from back to front.

Consume foods and liquids that stimulate saliva production

In addition to water, certain foods – like sugar-free gum, popsicles or lozenges – help us salivate more than others. And when we have dry mouth, this is exactly what we need. You may also find it helpful to chew on ice.

Avoid certain drying foods and drinks

You can help prevent dry mouth by avoiding spicy, acidic and hot foods, and refraining from foods that are crunchy, chewy, hard or dry. This also includes foods that absorb saliva, like breads and crackers, and diuretics like coffee. Choose a diet that consists mostly of soft, bland foods with a high liquid content, like soups, stews and meals with gravy or other sauces.

Try artificial saliva

There are several brands of over-the-counter artificial saliva available to temporarily relieve the symptoms of dry mouth. While artificial saliva can provide a protective layer of moisture over mouth tissue, it doesn’t stimulate the salivary glands. Plus, artificial saliva is missing the beneficial compounds that aid in oral health and digestion.

When to see a doctor or dentist for dry mouth treatment

If you are experiencing persistent dry mouth, you may want to see your primary care doctor or a dentist. Make an appointment if:

• Scaly white patches appear inside your mouth
• Your mouth starts to burn or sting
• Swallowing becomes very difficult

Your doctor or dentist can help determine the underlying cause of your dry mouth and work with you to create a personalized treatment plan that could include special mouthwashes or oral sprays to encourage saliva production. Your primary care provider can refer you to a specialist or suggest alternative treatments if your prescription medicine is the reason behind your dry mouth.

Chronic dry mouth is more than just uncomfortable – it could be your body telling you that something more is going on. Pay attention to the signals your body is sending and talk to a doctor if your symptoms don’t go away over time.