Spring is in the air, and so are the tree pollens. Millions of people suffer this time of the year from sneezing, scratchy, itchy eyes, nose and throats, nasal congestion and chronic cough. It's also a given that if you have allergies, you won't sleep as well, along with everything from asthma, cough, and sinusitis to diarrhea. So how do allergies cause sleep problems, and in general, and how does it specifically cause or aggravate obstructive sleep apnea?
When Allergies Lead to Something Worse
There are already tomes of articles, books and websites offering tips for allergy sufferers including traditional options like nasal saline irrigation, homeopathic remedies, and using a HEPA filter to prescription medications and allergy shots. But again, how can having a runny nose cause you not to sleep well at night? I've combed through numerous medical and internet resources and to date, I haven't found one good explanation.
However, looking at it from a sleep-breathing standpoint, it makes total sense: any degree of nasal congestion, whether from allergies, colds, or even weather changes, causes a slight vacuum effect downstream in the throat which can aggravate tongue collapse, especially in certain susceptible people. Who then, are susceptible to tongue collapse? Almost every modern human!
It's All In Your Jaws
To be more specific, the smaller your jaws, the more likely you'll sleep poorly when you have allergies. Even if you're completely normal, having a stuffy nose can suddenly cause your tongue to fall back and block your breathing. Plugging your nose has been shown to cause obstructions and arousals during sleep. This is why you'll toss and turn when you have an allergy or a simple cold.
Many people with allergies and small mouths will also have grooves or indentations along the side of their tongues. This is called tongue scalloping. Since the tongue and other soft tissues grow to their genetically predetermined size, and due to crowding from having smaller jaws, the teeth leave their imprints along the side of the tongue. If you have additional inflammation from gastric reflux that's a given with sleep-breathing problems, then this scalloping problem gets worse. Not too surprisingly, tongue scalloping is predictive of having apneas, hypopneas, or oxygen drops in almost 90% of people.
Allergies From Stress?
So then, why do allergies happen in the first place? Again, there are tons of proposed explanations that I don't have the space for, but here's a simple concept from Robert Sapolsky's classic book, Why Zebras Don't Get Ulcers :
Humans can handle big stresses such as a major catastrophe, a death in the family, or running away from a tiger. In these scenarios, your stress response leads to an intense activation of your immune system (in addition to your nervous system's fight or flight response). Once the stress is over, your immune system's activity level drops down to normal, but only after it dips below normal for a short period of time. During this short period, you're also more susceptible to getting sick.
However, modern societies don't have very big stresses such as running from a saber tooth tiger. Rather, we have multiple micro-stresses spread throughout the day such as being honked from the rear on the way to work, your boss yelling at you, or your computer crashing. These little stresses push your immune system's activity higher and higher, with not enough time for it to recover and go back to normal levels. After a certain point, your immune system is on constant overdrive, leading to the typical allergic or autoimmune conditions that are all-too-common today.
When Your Allergy is Not An Allergy
This process also explains why you may also have a chronically runny nose. This is called chronic or nonallergic rhinitis, when the involuntary nervous system in your nose overreacts to irritants, chemical, odors, or weather changes (either pressure, temperature, or humidity changes). Symptoms include runny nose, sneezing, nasal congestion, post-nasal drip and headaches, and is often mistaken for regular allergies. This condition may respond to regular allergy medications, but not as well. Either way, inflammation and swelling can also cause nasal congestion, leading to poor quality sleep.
Overcoming Your Allergies
If you have classic allergies, you must start with the basics: Avoid outdoor activity on high-pollen days, shower before bedtime to get the allergies out of your hair, don't wear shoes indoors, get a HEPA filter, and take over-the-counter medications as needed. Some people benefit from routine use of HEPA filters as well in their bedrooms. You may have to see your doctor if conservative measures don't help.
There are various over-the-counter allergy medications. The newer, nonsedating antihistamines block the effects of histamine, which is what causes watery, itchy, runny eyes and nose. The most common brands are Claritin, Allegra, and Zyrtec. They all work differently in different people, so the only thing you can do is to try each one and see which you prefer. Although they are nonsedating in theory, there are reported cases of drowsiness with all three. Benadryl is an older antihistamine that's very effective for allergies, except that many more people may get drowsy.
If your nose is stuffy, then two options are nasal decongestant sprays (which you can only use for 2-3 days) or decongestant pills. Routine nasal saline irrigation can also help your breathing and sleep.
There are a number of prescription medications, including topical nasal steroid or topical steroid sprays. Leukotriene phosphate inhibitors, such as Singulair, and various others also available. Oral steroids can also be useful in emergency situations. As a last resort, an allergy evaluation with shots are a consideration.
Regardless of which way you treat your allergies, it's important to follow all my recommendations for better breathing while sleeping, such as avoiding eating or drinking alcohol within 3-4 hours of bedtime, sleeping on your side or stomach. Having a stuffy nose for whatever reason can trigger breathing pauses downstream, ultimately giving you a bad night's sleep.