Dry mouth, clinically known as xerostomia, is a common side effect during a respiratory illness. This condition occurs when the salivary glands do not produce enough saliva to keep the mouth moist, resulting in a sticky or parched sensation. A cold definitively causes dry mouth, as the illness introduces multiple physiological stressors that directly or indirectly reduce saliva flow.
The Mechanism: Why Colds Trigger Dry Mouth
The primary mechanical driver of dry mouth is nasal obstruction, which forces a shift from nasal breathing to mouth breathing. When the nose is congested, the individual naturally breathes through the mouth, especially while sleeping. This constant airflow across the oral tissues leads to rapid evaporation of the thin layer of saliva, diminishing its protective and lubricating properties.
Systemic dehydration also plays a significant role in reducing the body’s overall fluid reserves necessary for saliva production. Fighting a viral infection often involves fever, which increases fluid loss through perspiration, and the body diverts water toward immune responses. This fluid imbalance decreases the volume of saliva produced, making the remaining saliva feel thicker or stringy.
Furthermore, many over-the-counter cold and flu medications can exacerbate the problem. Decongestants and especially antihistamines work by drying up mucous membranes to relieve a runny nose and post-nasal drip. This drying effect, known as an anticholinergic side effect, extends to the salivary glands, actively reducing saliva secretion.
Recognizing the Signs of Dry Mouth
Identifying dry mouth involves a collection of specific oral symptoms beyond the simple feeling of thirst. One common sign is a persistent sticky or tacky sensation, often feeling as though the tongue is adhering to the roof of the mouth. Reduced saliva also makes basic functions difficult, leading to trouble when attempting to speak, chew, or swallow food.
The lack of cleansing saliva allows bacteria to flourish, often resulting in temporary bad breath, or halitosis. Constant exposure to air can cause the lips to crack, become chapped, or split at the corners of the mouth. Internally, the tongue may appear dry, red, or grooved, and some individuals report a change in how they perceive tastes.
Practical Steps for Relief During Illness
Managing dry mouth involves focusing on rehydration and stimulating the flow of remaining saliva. The most straightforward strategy is frequent hydration, meaning taking small sips of plain water throughout the day rather than drinking large amounts all at once. Keeping water within reach, especially on a bedside table, helps counteract the moisture loss that occurs overnight.
Using a cool-mist humidifier in the bedroom is an effective measure, as it adds moisture to the air and helps reduce the evaporative effect of mouth breathing. To stimulate the salivary glands, sucking on sugar-free candies or lozenges, or chewing sugar-free gum, encourages mechanical saliva production. These methods provide a temporary boost to oral moisture without introducing cavity-causing sugars.
For persistent dryness, over-the-counter oral moisturizers, such as specialized gels, sprays, or rinses designed for xerostomia, can provide temporary relief. These products coat the oral tissues and mimic the lubricating quality of natural saliva. To prevent worsening the condition, limit the intake of beverages containing caffeine or alcohol, as both substances can have diuretic or drying effects.