How Do I Know If My Postnasal Drip Is Allergy or Acid Reflux?

Postnasal drip is mucus, and there are basically three types. The first type is clear and thin and caused by allergy, i.e., allergic rhinitis. The second type, caused by respiratory reflux, is thick and usually white, it looks like Elmer’s Glue. The third is yellow or green and is usually associated with infection … not the topic of this post.

What Is Mucus and What Does It Do?

Mucous membranes line the respiratory tract — the lining of the nose, sinuses, and throat—the entire respiratory tract. It may come as no surprise, but mucous membranes secrete mucus. Under normal circumstances, the nose and throat make about a quart of mucus daily. Usually, normal mucus is swallowed unnoticed.

The respiratory system’s mucus has many functions, but its two most important are the lubrication and barrier functions; inhaled viruses, bacteria, and particulate matter are trapped on and in this sticky layer, which prevents such foreign material from being absorbed or attacking us all the time. 

When the mucus membranes are irritated or inflamed, they produce excess mucus. Common causes include allergy, acid reflux, and much less commonly inhaled irritants.

How Do I Know If My Postnasal Drip Is Allergy?

Several medical conditions result in different quantities, consistency, and color of respiratory tract mucus. With inhalant allergies to things like dust, mold, pollen, and grass, the consistency of the mucus is usually watery, thin, and transparent, almost like strands of glass. 

Some people with allergic rhinitis, for example, have to walk around carrying a box of tissues. When exposed to an inciting allergen, they usually have sudden related symptoms such as stuffy nose, runny nose, sneezing, and watery, red, or swollen eyes. 

People with allergic rhinitis (nose) have attacks when they come in contact with their offending allergens. When a knowledgeable physician examines patients with allergic rhinitis, the usual findings are a boggy, swollen, purplish nasal lining with a thin, clear-as-glass mucus. 

Antihistamine medications and steroid inhalers can successfully treat allergic rhinitis. However, the steroid inhalers must be used twice daily for weeks before any benefit is realized; relief is not immediately following a spray. Note that many people with constant “allergic” symptoms actually have respiratory reflux. Chronic throat clearing, for example, is not a symptom of allergy.

How Is Respiratory Reflux Postnasal Drip Different Than Allergy? 

Respiratory reflux mucus is thick and associated with reflux symptoms. With almost 75,000 people responding to a survey of acid reflux symptoms, post-nasal drip was the number one symptom, and chronic throat clearing was the second most common.

The consistency of reflux-caused mucus is thicker than that of allergy, and for the sufferer, the mucus is sticky and hard to move, especially when it gets stuck on the vocal cords. On examination, reflux-caused mucus is thick, white, and widely dispersed in the nose and throat, especially on the back wall of the pharynx (the throat).

This photo of a throat shows the thick white mucus associated with respiratory reflux dripping down from the back of the nose, i.e., postnatal drip. Other respiratory reflux findings include redness and cobble-stoning of the lining at the back of the throat. Allergy mucus looks nothing like this.

Why Are Allergy and Reflux So Often Confused?

All post-nasal drip is not an allergy, and most self-diagnosing, self-treating patients falsely assume that their post-nasal drip is due to allergy when, in fact, they have silent respiratory reflux. With reflux, patients can also have nasal congestion (especially in the morning), but not usually with runny nose, sneezing, or itchy eyes. 

Many physicians are unaware of the clinical differences between allergy and reflux; specifically, they are ignorant of the different physical findings, including the difference in the consistency and color of the mucus.

Can Reflux Cause Sinus Symptoms?

Respiratory reflux causes most sinus symptoms. The nasal sinuses (maxillary, ethmoid, sphenoid, and frontal) are hollow cavities in the face (the cheek areas, around and above the eyes); and what they all have in common is that they have ostia (openings) that allow them to breathe and drain into the nose. 

Respiratory reflux can cause swelling of the ostia, resulting in facial fullness, pain, and sinus-like symptoms. Today, many unnecessary sinus and nasal procedures are performed when the real problem is respiratory reflux. 

Other Observations

Post-nasal drip is just a symptom, not a diagnosis. It does not cause other conditions or diseases, such as sinus disease or sore throat, and chronic cough is virtually never due to it. 

Besides reflux and allergy, certain infections, chemical fumes, or irritants can cause too much mucus and post-nasal drip. A true sinus infection may cause sour-tasting, green, or yellow mucus.

Sometimes, postnasal drip can be confused with a condition called water brash, which is actually a symptom of esophageal reflux (GERD). Water brash is excessive salivation that occurs in response to esophageal acid reflux. 

In the winter, in cold, dry environments everyone gets some degree of thick mucus postnatal drip.

If you have thick postnasal drip from respiratory reflux, it tends to resolve slowly, sometimes taking months— as if war-time mucus factories take some time to shut down.

Pearl of the Week

Here’s a question with an interesting answer that helps explain a lot. My book, Dropping Acid: The Reflux Diet Cookbook & Cure has been the #1 Best Seller in Asthma (Amazon) for years. Why? For 40 years, I have lectured to physicians, and they have been unresponsive to the idea that most shortness of breath, including asthma. is caused by respiratory reflux. But it is you, the layman, not the doctor, who understands the connection. That’s why my reflux book is the #1 Best Seller in Asthma. You get it; your doctor doesn’t.

Resources

If you’re interested in scheduling a virtual consultation with me, you can Book Online. Additionally, if you’re looking for more information regarding the diagnosis and treatment of respiratory reflux, I recommend checking out my two companion books on Amazon: Dropping Acid: The Reflux Diet Cookbook & Cure and Dr. Koufman’s Acid Reflux Diet. For those who suffer from chronic cough, I suggest looking at The Chronic Cough Enigma.