Can Allergies Cause Dry Mouth?

Approximately 8 percent of adults and 7 percent of children experience seasonal allergies. If you’re prone to seasonal allergies or frequent sinus infections, it’s important to note how these conditions — as well as the medications you take to manage them — may contribute to oral health problems like dry mouth, also known as xerostomia.

Seasonal Allergy Symptoms

Different types of pollen and spores, pet dander, dust mites, and other irritants can cause seasonal allergy symptoms to crop up. Common ones include sinus swelling or discomfort, itchy and watery eyes, nasal congestion, and sneezing.

But what about dry mouth? Allergies don’t decrease saliva flow. However, people may breathe through their mouths when they have nasal congestion, which can contribute to dry mouth. Moreover, allergy drugs tend to dry out our mouths and other parts of our bodies, which we’ll discuss more later. So, while not necessarily a symptom, dry mouth (as well as other oral conditions) may appear as a byproduct of allergy symptoms and the management of these symptoms.

Allergy Impacts on Oral Health

Research shows people with allergies tend to have more problems with their oral health, including an increased risk of dry mouth, cavities, gingivitis, and gum disease. These oral health concerns could be due to a number of factors.

Below, we dive deeper into some oral health problems associated with seasonal allergies.

Dry Mouth

Dry mouths are a safe haven for oral bacteria, increasing the likelihood of gum infections and tooth decay. Mouth breathing because of blocked nasal sinuses or the drying effect of some allergy medications can trigger this condition.

According to the American Dental Association, medications like decongestants often list xerostomia as one of the most common side effects. Because these types of medications — whether prescription or over-the-counter — act as agents that “dry up” mucus in the sinuses, they also reduce normal saliva production during the process. In turn, this reduction creates a dry mouth environment for several hours thereafter.

If you’re taking medications to manage your allergy symptoms, it’s extremely important to counteract the effects of dry mouth by staying hydrated and improving your oral hygiene routine. Otherwise, dry mouth may lead to more complex oral health conditions.

Post-Nasal Drip

About 12 percent of American adults are diagnosed with sinusitis every year. Of these, many experience what’s called a “post-nasal drip,” or drainage behind the nose that runs down the back of the throat. Post-nasal drips can cause a foul odor due to the thick mucus and bacteria in the back of the mouth, amplified by mouth breathing if you have blocked nasal passages. The constant tickle the post-nasal drip creates can also contribute to coughing and a sore throat.

If you have a post-nasal drip, congested sinuses, and dry mouth symptoms, good oral hygiene can help limit odors and irritation in your throat.

Sore Throat

Along with viruses or bacterial infections such as strep throat, sore throat symptoms can also be attributed to seasonal allergies. As mentioned before, post-nasal drips can contribute to a sore throat due to drainage down the back of the throat, tickling or scratching it.

Gargling with warm salt water can help relieve mild sore throat symptoms like itchiness, swollen tonsils, or redness. Rinsing with alcohol-free mouthwash can help manage bacterial levels while improving how your breath smells, especially if you’re experiencing a post-nasal drip.

Pressure

Chances are, if you’ve had allergies for more than a day or two, you’re feeling pressure building up in your sinuses and across your forehead. Due to the sinus lining pressing against the roots of the upper back teeth (molars), the nasal pressure can feel similar to a toothache. Until you treat your sinus pressure with medication, it may be difficult to self-diagnose where the pain is coming from. And with dry sinuses and dry mouth, your teeth may feel extra sensitive, leaving you uncomfortable. If the symptoms of tooth pain or sensitivity don’t improve within a few days of your allergies clearing up, be sure to see your dentist.

Antihistamines

Can allergies cause dry mouth? The antihistamines we take to manage them might. As said before, common medications that counteract allergy symptoms also dry out our saliva glands. Though decongestants can also play a role, antihistamines are usually the culprit.

Should you avoid antihistamines or decongestants if you have allergies? You may not want to since they help relieve allergies and nasal congestion. If you don’t treat your seasonal allergies, you run the risk of sinusitis evolving into an infection or bacteria spreading into your upper airway. However, it’s important to be aware of the side effects of these treatments on your mouth to help prevent complications.

Temporary use of antihistamines to manage seasonal allergies will not inherently cause serious, long-term dental complications. But given the fact that they cause dry mouth — which increases the rate of tooth decay — you should complement treatment with antihistamines or other allergy medication with an oral hygiene routine that targets dry mouth and cavity prevention.

Allergies, Dry Mouth, and Bad Breath

Since most people tend to breathe through their mouths when their noses are stuffy, allergies can contribute to bad breath in addition to dry mouth. The same idea applies to antihistamines and decongestants, which have a drying effect. Because dry mouth produces a bacteria-friendly environment, with no saliva to help wash the odor-causing bacteria away, it can lead to bad breath.

Prevention

Seasonal allergies often flare up during changes in the weather, when pollen counts rise, or even if it’s been dry or rainy in the area. Take an antihistamine at the onset of seasonal allergies to help you get ahead of symptoms like a sore throat or runny nose, as well as the associated oral health problems such as dry mouth — or at least make them less severe!

At the same time, watch for signs of dry mouth while you’re taking allergy medications because the lack of saliva will increase the amount of bacterial plaque present, reduce hydration around your teeth, and create an environment where cavity-causing bacteria will thrive. If you’re already at risk for recurring cavities, it’s vital to stay ahead of tooth demineralization.

As a good habit, brush twice a day with fluoride toothpaste to help remineralize any weaker tooth structures. Also, floss or use a water flosser to clean between your teeth and under the gumlines, where toothbrush bristles don’t reach. Follow up with an alcohol-free mouth rinse designed for dry mouth to flush away any leftover bacteria and improve bad breath caused by allergies.

Conclusion

Most people with seasonal allergy symptoms will notice some changes in their mouth as well, whether it’s dry mouth or bad breath. Thankfully, managing your condition with the right medications paired with proactive oral health strategies can minimize the impact allergies have on your oral health.