Dry mouth, medically known as xerostomia, is the subjective sensation of having insufficient saliva to keep the mouth moist. While asthma itself does not directly cause dry mouth, the condition is strongly linked to the medications used to manage asthma and the altered breathing patterns that often accompany the respiratory disease. This dryness can range from mild discomfort to a significant issue that affects oral health and quality of life.
Asthma Medications as a Primary Factor
Many common asthma treatments can reduce the body’s ability to produce saliva, leading to xerostomia. The mechanism often involves anticholinergic effects, which interfere with the signaling pathway that stimulates salivary gland secretion. Bronchodilators, particularly long-acting and short-acting beta-agonists (like albuterol and salmeterol), are known to decrease salivary flow rates.
These medications affect the autonomic nervous system, which regulates bodily secretions. By blocking acetylcholine receptors, these drugs reduce the volume of saliva produced by the glands. Even though they are delivered through an inhaler, the systemic absorption of these agents can still exert a drying effect on the salivary glands.
Inhaled corticosteroids (ICs), which are the foundation of long-term asthma control, have also been associated with xerostomia. Studies suggest that higher doses of ICs may diminish the production of protective salivary components, such as the protein MUC5B, which is important for mucosal lubrication.
How Altered Breathing Patterns Contribute
Beyond medication, the physical symptoms of asthma, such as airway restriction, force many individuals to breathe through their mouths, contributing to dryness. When a person experiences wheezing or shortness of breath, they often instinctively switch from nasal to oral breathing to maximize air intake. This is especially common during intense breathing episodes, physical activity, or while sleeping.
Chronic mouth breathing leads to a constant and accelerated evaporation of moisture from the oral cavity. The continuous flow of air across the tongue and mucous membranes dries out the saliva much faster than when breathing through the nose. This physiological process reduces the protective functions of saliva, which include neutralizing acids and washing away food particles and bacteria.
The rapid, shallow breathing that characterizes an asthma flare-up further increases this evaporation. This mechanism of dryness is independent of the pharmacological side effects, creating a dual risk for people managing asthma. Maintaining good asthma control can indirectly help reduce dry mouth by lessening the need for mouth breathing.
Strategies for Managing Dry Mouth
Managing xerostomia involves a combination of preventative habits and over-the-counter support to replace lost moisture and stimulate natural saliva flow. A simple, effective step is to rinse the mouth with water immediately after using an inhaler to remove any residual medication. Following this with a large sip of water helps to hydrate the system.
To stimulate saliva production, individuals can suck on sugar-free hard candies or chew sugar-free gum, as the mechanical action encourages salivary flow. Sipping water frequently throughout the day is also helpful to keep the mouth consistently moist. Using a humidifier, especially at night, can reduce the environmental dryness that exacerbates mouth breathing effects during sleep.
For persistent or severe dryness, over-the-counter saliva substitutes, such as moisturizing sprays or gels, can provide temporary relief by coating the oral tissues. Because reduced saliva increases the risk of tooth decay, maintaining diligent oral hygiene is particularly important for people with asthma. This includes regular brushing with fluoride toothpaste and routine dental check-ups.