CPAP Cough: Understanding the Connection Between CPAP Use, Chronic Cough, and Obstructive Sleep Apnea

Coughing is a common bodily response to irritants in the throat or airways, but for some individuals, especially those with sleep apnea, coughing may become a more persistent issue, especially when using a Continuous Positive Airway Pressure (CPAP) machine. CPAP therapy is a leading treatment for obstructive sleep apnea (OSA), a condition in which the airway repeatedly collapses during sleep.

In certain cases, obstructive sleep apnea syndrome can be a significant cause of chronic cough, requiring tailored treatment plans to address both conditions simultaneously. While CPAP therapy is highly effective in treating OSA, some users may develop or worsen a cough, raising questions about the relationship between CPAP use and chronic cough. 

This article explores in detail what CPAP cough is, its causes, symptoms, and management, and how CPAP use impacts chronic cough and overall health.

What is CPAP Cough?

CPAP cough refers to a persistent cough experienced by patients using a CPAP machine. This can be a dry, hacking cough or one that produces mucus. CPAP users may experience coughing for several reasons, including irritation from the mask, nasal congestion, or postnasal drip. In some cases, CPAP cough can be an indication of an underlying issue with the device, such as poor hygiene or improper settings.

The term chronic cough is typically defined as a cough lasting more than eight weeks. For patients with obstructive sleep apnea, the use of CPAP therapy can sometimes trigger or exacerbate chronic coughing, but it can also provide relief for those who previously suffered from a cough related to sleep apnea.

Types of Cough Associated with CPAP Use

Causes of CPAP Cough

Coughing during CPAP therapy can stem from individual factors like physiology, sleep apnea severity, equipment settings (such as humidity, mask fit, and pressure), respiratory conditions, environmental allergens, and equipment hygiene, making it essential for users to recognize these causes to identify adjustments for improved comfort.

Dry Air 

CPAP machines deliver a steady stream of pressurized air to keep the airway open. However, when this air is too dry, it can irritate the respiratory system, leading to a dry throat and coughing.

Nasal Congestion and Postnasal Drip 

Some CPAP users experience nasal congestion or postnasal drip, which can trigger a cough. The increased airflow can exacerbate mucus production in the nasal passages, leading to coughing, especially during the night.

CPAP Humidity Levels 

Insufficient humidity in the CPAP machine can dry out the nasal passages, leading to irritation and coughing. On the other hand, too much humidity can cause condensation in the tubing, resulting in "rainout," which can also cause coughing.

Mask Leaks 

If the CPAP mask does not fit properly, air leaks can cause dryness and irritation of the nasal passages or throat, leading to coughing. Mask leaks are more common in patients using nasal masks or full-face masks with ill-fitting headgear.

CPAP Device Hygiene 

Improper cleaning of CPAP equipment, especially the mask and tubing, can result in the buildup of bacteria, dust, or mold. Inhaling these particles during sleep can irritate the lungs, leading to a cough. CPAP users must follow a strict cleaning schedule to avoid infections and minimize the risk of respiratory issues.

CPAP Pressure Settings 

If the CPAP pressure settings are too high, the increased airflow can irritate the airway, causing a cough. Patients with obstructive sleep apnea who are new to CPAP therapy may need time to adjust to the pressure, or they may require adjustments to their machine settings for comfort.

Allergies or Asthma 

Patients with pre-existing respiratory conditions, such as asthma or allergies, are more susceptible to developing a cough when using a CPAP machine. CPAP therapy can exacerbate symptoms of these conditions if the airflow triggers allergic responses or asthma attacks.

Common Causes of Cough in CPAP Users

Can CPAP Therapy Cause Coughing?

CPAP therapy itself is not typically the direct cause of coughing, but various factors related to the machine’s use can trigger or worsen cough symptoms, particularly in patients prone to respiratory issues. One of the most common causes of coughing during CPAP therapy is dry air. CPAP machines deliver continuous positive airway pressure to keep the airway open, but the pressurized air can dry out the nasal passages and throat, leading to irritation and, in some cases, coughing.

• Another contributing factor is nasal congestion. Patients who experience allergies or sinus issues may find it difficult to breathe through their nose, leading them to open their mouth during sleep. This mouth breathing can exacerbate dryness in the throat, causing irritation and coughing. Additionally, mask leaks can allow air to escape from the mask and dry out the surrounding skin and throat, further contributing to discomfort and cough.
• For individuals with pre-existing conditions like gastroesophageal reflux disease (GERD) or postnasal drip, CPAP therapy may increase pressure in the airway, aggravating these conditions and causing a cough.
• To prevent CPAP-related cough, patients can make adjustments such as using a heated humidifier to add moisture to the air, ensuring the CPAP mask fits properly to avoid air leaks, and addressing any nasal congestion before therapy with nasal sprays or saline rinses. Taking these steps can help alleviate coughing while maintaining effective CPAP treatment.

Can Sleep Apnea Cause Coughing?

Obstructive sleep apnea (OSA), a condition where the airway becomes blocked during sleep, can lead to coughing in some patients, particularly in those with undiagnosed or untreated sleep apnea. The repeated collapse of the airway can irritate the throat and cause postnasal drip, leading to a chronic cough.

Patients with OSA may experience interrupted breathing events called apneas and hypopneas, which cause a drop in oxygen levels (hypoxia). Cough hypersensitivity can develop in patients with chronic cough due to obstructive sleep apnea. This means the throat becomes more sensitive to minor irritants, resulting in frequent coughing. A sleep study can be useful in evaluating the relationship between cough severity and chronic cough and OSA, helping determine the best treatment course.

CPAP Therapy and Chronic Cough

While CPAP therapy is primarily designed to improve breathing during sleep and reduce symptoms of obstructive sleep apnea, it can also help alleviate symptoms of chronic cough for many patients. This is particularly true for individuals whose cough is linked to sleep apnea or related conditions, such as gastroesophageal reflux disease (GERD).

A study of CPAP therapy in patients with both chronic cough and obstructive sleep apnea found that CPAP use significantly reduced the frequency and severity of coughing over time. CPAP helps to keep the airway open, reducing the likelihood of postnasal drip and minimizing irritants that can trigger coughing.

For patients with both chronic cough and obstructive sleep apnea, the use of CPAP therapy can bring significant relief. Many sleep medicine specialists recommend CPAP therapy as an effective solution for managing obstructive sleep apnea syndrome and associated symptoms, including chronic cough in patients.However, for some individuals, coughing may persist due to underlying conditions or improper use of the CPAP machine. Addressing these factors is essential for optimizing therapy and improving sleep quality.

A longitudinal study of CPAP use in patients with chronic cough revealed that the use of CPAP therapy led to a significant reduction in the severity of coughing, especially when patients followed a strict treatment protocol, including proper cleaning and maintenance of their CPAP equipment.

Managing CPAP-Related Cough

If you experience a persistent cough after starting CPAP therapy, there are several steps you can take to alleviate the symptoms and improve your comfort. These include:

Humidification Adjustments 

• One of the most common causes of coughing during CPAP therapy is dry air. The continuous stream of pressurized air delivered by the machine can dry out the nasal passages and throat, leading to irritation and coughing. To combat this, adding a heated humidifier to your CPAP machine or adjusting the humidity settings can provide much-needed moisture to the airway.
• Heated humidifiers add warmth and moisture to the airflow, which helps soothe dry nasal passages and prevent throat irritation. If you already use a humidifier, try increasing the humidity levels to find the right balance that keeps your throat and nasal passages moist without causing condensation in the tubing.

Nasal Saline Rinses 

• Using a nasal saline rinse or spray before bed can help flush out irritants, clear congestion, and open up the nasal passages, which can ease breathing during CPAP therapy. A saline rinse can also reduce postnasal drip, a common contributor to CPAP-related cough. 
• Saline sprays are a natural way to moisturize your nasal passages, ensuring smoother airflow while using your CPAP machine. You can also use a saline rinse in combination with your humidifier for maximum moisture and comfort throughout the night.

Proper Mask Fit 

• A poorly fitting CPAP mask can cause air leaks, which lead to dryness in the throat and mouth, increasing the likelihood of coughing. Ensuring that your CPAP mask fits properly is essential to reduce air leaks and maintain effective therapy.
• Choose the right mask type that accommodates your sleep style and comfort level, whether it’s a nasal mask, full-face mask, or nasal pillow. Adjust the headgear so that it holds the mask securely without overtightening, which can lead to discomfort and create small air leaks.
• Regularly check the mask cushions for wear and tear, and replace them as necessary to maintain a proper seal and prevent dryness that may lead to coughing.

CPAP Pressure Adjustments 

• Sometimes, a CPAP machine’s pressure settings may be too high, which can cause airway irritation and trigger coughing. If you find yourself coughing frequently while using CPAP, talk to your doctor about adjusting the pressure settings.
• Expiratory Pressure Relief (EPR) is a feature found in many CPAP machines that lowers the pressure during exhalation, making it easier to breathe out and reducing discomfort that may lead to coughing. Your doctor may also recommend switching to an Auto-CPAP (APAP) machine, which automatically adjusts the pressure levels based on your needs throughout the night.
• Adjusting the pressure to a more comfortable level can reduce the strain on your airway, helping to alleviate coughing and improve overall sleep quality.

Cleaning Your CPAP Equipment 

• Proper hygiene is crucial when using a CPAP machine to prevent respiratory infections that can cause or exacerbate coughing. Over time, bacteria, dust, and mold can accumulate in the mask, tubing, and humidifier, leading to coughing and other respiratory issues.
• Daily cleaning of your CPAP mask, tubing, and humidifier with mild soap and water is essential to remove contaminants. Replace your CPAP filters and mask cushions regularly, following the manufacturer’s guidelines to ensure cleanliness and prevent irritants from being inhaled. Allow all CPAP equipment to air-dry thoroughly to avoid moisture buildup, which can harbor mold and bacteria.
• By keeping your CPAP equipment clean, you minimize the risk of developing coughs due to infection or inhalation of irritants. Regular CPAP cleaning is crucial to avoid potential infections and to ensure the machine does not contribute to irritation or effect on chronic cough.

Addressing GERD 

• For some CPAP users, coughing may be related to gastroesophageal reflux disease (GERD), as the increased pressure from the machine can aggravate acid reflux. This can result in irritation in the throat and esophagus, leading to coughing.
• Treating GERD with medications such as antacids or proton pump inhibitors may help reduce symptoms and alleviate coughing. Lifestyle changes, such as avoiding late meals, elevating the head during sleep, and cutting back on acidic or spicy foods, can also help manage GERD and reduce coughing during CPAP therapy.
• Addressing GERD and its impact on coughing can enhance the overall effectiveness of CPAP therapy and improve comfort during sleep. By managing both sleep apnea and GERD, sleep apnea patients can experience relief from both conditions.

Consult Your Doctor

In some cases, a chronic cough after starting CPAP therapy may not be directly related to the CPAP device itself. Instead, it could be a sign of an underlying health issue that needs attention, whether or not it's linked to your sleep apnea. If your cough persists despite making adjustments to your CPAP therapy, it’s essential to consult your doctor. Patients experiencing a deep cough or increased cough frequency should consult their doctor to determine if it is caused by the CPAP or an unrelated issue. A persistent cough could be caused by a range of other health conditions, so discussing potential causes with your healthcare provider is important to ensure proper diagnosis and treatment.

Steps for Managing CPAP-Related Cough

Conclusion

CPAP therapy is a highly effective treatment for obstructive sleep apnea patients, helping to manage obstructive sleep apnea severity and improve overall quality of life. The effect of CPAP therapy on chronic cough varies among individuals, but many studies show an improvement in cough severity after consistent CPAP use. However, for some, following CPAP therapy, a chronic cough may develop. This can be caused by factors such as improper mask fit, dry air, or underlying health issues. Patients treated with CPAP may experience a cough due to mask leaks or nasal dryness, both of which can be managed through adjustments to the CPAP machine, including adding humidification, or cleaning the equipment to prevent CPAP infections.

Waking up with a cough is not uncommon for those new to using the CPAP machine, but it is essential to monitor the effect of CPAP on cough sensitivity. By addressing these issues early on, obstructive sleep apnea patients can avoid unnecessary discomfort. Consulting with a healthcare provider for a sleep apnea study or to discuss changes in symptoms may help.

The benefit of CPAP therapy often outweighs the side effects such as coughing, especially when patients receive proper management of chronic cough through continuous positive airway pressure treatment. For patients in the chronic CPAP population, improvements with CPAP are common when used consistently and appropriately. With the right adjustments, including possible changes in CPAP machine use, patients can see a change in cough sensitivity and an overall improvement in their symptoms. If a cough persists or worsens, seeking medical advice is crucial for further evaluation and management.