CPAP side effects and what to do about them

Dry mouth, swallowed air, a mark on the bridge of the nose, and the feeling that the mask is a box on your face are common on CPAP. They are usually a humidity, leak, pressure, or interface problem. The 2019 AASM PAP guideline treats those problems as things to troubleshoot, not as a verdict that you “cannot do CPAP.”

Which side effects show up often, and which are urgent?

Patil and colleagues, writing the American Academy of Sleep Medicine clinical practice guideline in 2019, listed nasal dryness or irritation, dry mouth, sore throat, and sinus infection among potential harms of PAP, along with loss of intimacy. They judged those harms mitigable with appropriate interventions, or reversible if PAP is stopped. The companion systematic review points readers to a side-effect table in the supplement and notes that side effects can fragment sleep and reduce use, so clinicians should monitor and manage them.

Shirlaw’s 2017 aerophagia trial, in its background, names claustrophobia, nasal dryness, pressure intolerance, and interface leak (with sleep fragmentation) as recognized CPAP side effects, and aerophagia or bloating as another. That list matches what we hear in clinic. It is not a ranked Ohio frequency table. We do not have a published count of which complaint is most common in this practice. if the office wants a local ranking before anyone claims one.

Urgent is different from unpleasant. Chest pain, new wheeze, facial swelling after a product change, or vomiting that you cannot explain belongs in urgent care or an emergency department, not in a mask-adjustment anecdote. What follows is the ordinary cluster: dryness, aerophagia, claustrophobia, skin marks, and the leak that gets mislabeled as all of the above. The overview of how PAP works lives on the CPAP therapy page. This article is the complaint list.

Why does CPAP dry your mouth, and does the humidifier actually help?

Two different dryness problems get one name. Nasal dryness is air moving through the nose all night without enough moisture. Dry mouth is often mouth leak: the lips part, pressurized air leaves through the mouth, and the oral mucosa desiccates. You can have both. Treating them as the same setting error wastes a visit.

Heated humidification is the intervention with guideline-level evidence for side effects. The AASM task force identified nine randomized trials of PAP with humidification versus PAP without. Meta-analyses showed a clinically significant reduction in several PAP-related side effects: dry mouth and throat, nasal discharge, nasal congestion, dry nose, bleeding nose, sinus pain or headache, sore throat, hoarse voice, and reduced smell. The same analyses did not show a clinically significant improvement in PAP adherence, sleepiness, or quality of life from adding humidity. The guideline still says clinicians should generally use heated humidification with PAP to reduce those side effects. That sentence is about comfort and tissue, not about hours on the download.

Rainout is the tradeoff the task force named: water condensing in the circuit, on the face, or in the nose or mouth. A heated tube, a lower humidity setting, or keeping the machine slightly below the bed can stop the drip. Turning humidity off because of one wet night returns you to the dryness the trials were treating.

If the mouth is dry and the report shows high leak, humidity alone will not close the lips. That is a mouth-leak problem. Chin support, a different nasal cushion, treating nasal obstruction so you are not forced to mouth-breathe, or, sometimes, an oronasal mask are the mechanical options. Jumping straight to a full-face mask is how people trade a dry mouth for a new leak at the nasal bridge. The leak article in this series is the physics. Here, the clinical tell is: dry mouth plus high unintentional leak points at an open mouth. Dry nose plus a good seal points at humidity.

What is aerophagia, and how is it different from a leak?

Aerophagia is swallowed air. Shirlaw and colleagues described it as pressurized air collecting in the gastrointestinal tract, with abdominal discomfort, excessive belching, and flatulence, sometimes severe enough that the patient stops CPAP. Their trial enrolled adults who attributed bloating, gas, belching, or abdominal pain to CPAP. It was a two-week, double-blind, randomized crossover of fixed CPAP versus APAP (6 to 20 cm H2O) in 56 analyzed subjects at an Australian tertiary sleep laboratory. Thirty-nine of 56 used full-face masks at recruitment. Subjects had been on therapy for almost a year and had been titrated to a little over 14 cm H2O.

APAP lowered median and 95th-centile pressure and leak compared with fixed CPAP. It reduced bloating, worst bloating, flatulence, and belching. It did not improve compliance compared with fixed CPAP in that already-adapted group. Residual AHI stayed in a clinically acceptable range on both arms. During the fixed-CPAP arm, aerophagia symptoms were lower with a nasal mask than with a full-face mask (19.1 versus 28.8 on their symptom scale, P = .019). Genta’s accompanying editorial called that a reason to switch patients with aerophagia from fixed CPAP to APAP, and further evidence against using oronasal CPAP as a default. Median pressure in Shirlaw’s APAP arm was 9.8 cm H2O in the nasal-versus-full-face subgroup table.

Leak is air escaping to the room. Aerophagia is air going into the esophagus. They can coexist. A high leak number on the download does not prove you swallowed the missing liters. A tight belly in the morning with a modest leak number is still aerophagia. The machine cannot see your stomach.

What we do in clinic follows that paper’s logic without promising the same numbers in your house. If aerophagia started after a pressure increase, we look at whether APAP, a lower fixed pressure that still treats the apnea, or a nasal interface is available. If you need the oronasal mask for mouth leak, we do not yank it off to chase a subgroup P value. We do not drop pressure so far that the apnea returns. Shirlaw warned that empiric pressure cuts can leave OSA under-treated. The download and how you feel both count.

What helps when the mask feels like a trap?

Claustrophobia on PAP is a real barrier. Patil’s systematic review, in the oronasal-versus-nasal side-effect discussion, reported one crossover trial in which higher scores for claustrophobia and difficulty exhaling were clinically significant with the oronasal interface, and all participants chose the nasal interface for long-term treatment. That is one trial, 20 people on the comfort rating in that paragraph, not a law. It is a reason to try nasal pillows or a smaller nasal mask before concluding that “CPAP” is the problem when the object on the face is a large oronasal shell.

Practice-level tactics that do not require a new randomized trial: wear the mask while awake, without pressure, for short intervals. Then add low pressure with the ramp. Sit up for the first minutes. A pillow style that sits at the nares rather than covering the midface changes the visual field. None of this is a guarantee you will like the device. AASM’s 2019 recommendations include a strong recommendation for educational intervention at PAP start and a conditional recommendation for behavioral and troubleshooting interventions in the initial period. Claustrophobia is a troubleshooting problem. It is also a reason some people move to a different therapy. That is a planned change, not a disappearing act with the machine in the garage.

Why do straps leave marks, and when is the skin breaking down?

A pink dent that fades after breakfast is strap pressure. Skin that stays red, weeps, or crusts is breakdown. The usual cause of the first is overtightening to chase a leak. Cushions seal by resting on the face with even contact. Extra strap tension flattens the silicone, lifts an edge, and leaks more, so the patient tightens again. The leak article covers that loop. The skin article is: loosen until the mask is stable and the leak graph is acceptable, not until the cheeks blanch.

Dirty cushions hold facial oils and detergent residue. ResMed’s cleaning page notes that antibacterial soaps can crack masks and lead to skin irritation and poor performance. If you started a new cleaner and the rash followed, stop the cleaner. If the rash follows the exact silicone footprint, size and material matter. Foam and silicone fail differently. A size too small pinches. A size too large balloons and rubs.

Do not put steroid cream inside the cushion “to toughen the skin” without a clinician. Do not ignore a pressure ulcer on the nasal bridge. That is a wound. Swap interfaces, add a barrier the manufacturer allows, or take nights off the offending mask while we refit. Untreated OSA is not a reason to grind a hole in the dorsum of the nose.

When is the problem pressure, and when is it the mask?

Pressure intolerance feels like fighting the machine on the exhale. Mask leak feels like air in the eyes or a raspberry sound at the cheek. Aerophagia feels like gas. Dry mouth feels like cotton. Naming the sensation saves a month of random setting changes.

Patil’s guideline found no clinically significant differences in adherence, sleepiness, or quality of life with modified expiratory pressure profiles versus standard PAP across the trials they meta-analyzed. Those comfort features may still help a given person. They are not a substitute for a mask that fits. The task force said clinicians should generally start with nasal or intranasal interfaces over oronasal or oral ones, while using the interface that minimizes side effects and optimizes efficacy and adherence for that patient. Fewer side effects were reported with nasal than with oronasal and oral interfaces in the studies they analyzed.

If side effects persist after humidity, a refit, and a pressure review, the conversation is whether PAP is the right tool. Westerville Sleep Center will have that conversation without treating it as a character test. CPAP alternatives exist for people who cannot use PAP despite troubleshooting. Call (614) 898-9340 or use the contact page and bring the device and every mask you have tried. Dr. Mahmoud Qadoom, MD, can read the leak and usage graphs with you. We do not promise that a new cushion will make you a nightly user. We do promise to name the side effect accurately before anyone throws the machine away.