Overview

Almost everyone has experienced that irritating feeling of a blocked, stuffy nose. Normally associated with the common cold, that bunged-up feeling for some people can persist causing frustration, difficulty breathing, difficulty sleeping, and a poorer quality of life. Post-nasal drip is another fairly common nasal condition, characterised by a constant feeling of mucus gathering in the back of the throat or dripping from the back of your nose. Nasal congestion and post-nasal drip often come hand in hand. Whilst irritating, it is important to understand the root causes to find the best treatments. Both nasal congestion and postnasal drip are ear, nose, and throat (ENT) conditions and can often come hand in hand. These two conditions can be linked for many reasons.^1,2

What is nasal congestion?

Nasal congestion is the feeling of blocked and stuffy nasal passages. Congestion causes the feeling of insufficient airflow, which is accompanied by pressure and excess mucus. It can be caused by many things, the most common of those being infections, allergies and irritants. There are also other less common causes, such as swollen adenoid glands, a nasal blockage or injury, as well as side effects of certain medications. 

Nasal congestion and mucus production together function as an immune protective mechanism that allows the entrapment of foreign particles such as bacteria, viruses, or allergens and allows their clearance from the airways. So to an extent, nasal congestion is a good thing however, if it persists, then it may pose a problem for you. Nasal congestion is one of the most common symptoms seen in primary and specialist care clinics. It can often be sorted with over-the-counter medication and at-home remedies however, persistent cases may require further medical attention.^1,3,4,5,6

What is a postnasal drip?

Post-nasal drip is a condition where mucus gathers at the back of the throat or drips from the back of the nose and causes a constant need to cough or clear the throat. As a result of this throat clearing, you may often develop a sore throat and hoarse voice. The causes of post-nasal drip vary from one person to another. Symptoms can be caused by infections including bacterial and viral, allergies (causing an allergic postnasal drip), or structural abnormalities such as a deviated septum. Additionally, certain medications such as birth control and blood pressure medications, age, pregnancy, Gastro-Oesophageal Reflux Disease (GORD) and trigger foods. Post-nasal drip is usually diagnosed by an ear, nose, and throat exam, a nasal endoscopy, and sometimes X-rays. Further tests may include allergy tests and gastrointestinal examinations. Understanding the cause of your post-nasal drip is vital in finding the best treatment.^2,7

The link between nasal congestion and postnasal drip

Mucus production and drainage

In a healthy individual, mucus is continually produced in manageable quantities, and it functions to moisten the airways and protect against any foreign invaders. This mucus is produced in the nose and throat and is subconsciously swallowed into the stomach to prevent it from building up and to destroy any bacteria or viruses that it has trapped within it. Nasal congestion occurs when the nasal passages become inflamed and the body begins to produce excess mucus to trap bacteria, viruses, and irritants. Therefore, the increased volume of mucus in the inflamed and congested nasal passages may cause mucus to build up in the throat, leading to postnasal drip.^4,7,8

Common causes

Nasal congestion and post-nasal drip can often have the same root causes, meaning a patient may experience both conditions at the same time. Infections are a common cause of these two conditions. Seasonal illnesses such as colds and flu are common causes of nasal congestion and therefore can be the reason behind associated post-nasal drip symptoms.⁹ 

Sinusitis

Sinusitis is another common cause of congestion and post-nasal drip. Sinusitis is inflammation of the sinuses following a viral or bacterial infection. Common symptoms of sinusitis are nasal congestion and increased mucus production. It is these symptoms together that can lead to post-nasal drip.^8,10

Allergens and Irritants

Allergens and irritants are another common cause of both nasal conditions. Allergens cause nasal congestion by triggering an aberrant immune response leading to inflamed airways and increased mucus production. Irritants, on the other hand, can lead to non-allergic rhinitis, which is the inflammation and congestion of the nose that is caused by something other than allergies. Similarly, there are also a lot of irritants that can trigger post-nasal drip, such as tobacco smoke and spicy foods.^2,7,8,11,12

Medications

Medications are another potential cause of congestion and therefore may make you at risk of developing post-nasal drip. These medications include but are not limited to, birth control pills, blood pressure medications, including alpha-blockers and beta-blockers, some antidepressants, and medications for erectile dysfunction. Please refer to the patient information leaflet of any medication that you take to check their specific side effects.¹³ 

Gastroesophageal reflux disease

Gastroesophageal reflux disease (GORD) is a cause unique to post-nasal drip. While the exact mechanism is unknown, it is suggested that the increase in stomach acid may mean that gastric juices are extending from the oesophagus to the airways. In this sense, antacids and proton pump inhibitors (PPIs) may provide relief.¹⁴

Treatment options

Treatments for nasal congestion

Decongestants will likely be the first-line treatment for nasal congestion. These can be bought over the counter from a pharmacist and function to reduce the inflammation in the airways. They can be in many formulations, such as nasal sprays or drops, tablets, or in liquid form. For congestion caused by allergens, antihistamines will be the port of call. Antihistamines counteract the chemicals in your body that are responsible for causing the symptoms of allergies. These can again be obtained from a pharmacist, but higher doses can be obtained from your GP.

Steroid nasal sprays are another form of medication that can be used to treat nasal congestion. These sprays are anti-inflammatory, so they will reduce the inflammation in the airways, leading to ease of airflow.  There are also at-home therapies that may help, including steam inhalation and saline nasal sprays.^6,9,15,16

Treatments for post-nasal drip

For post-nasal drip caused by bacterial infections, antibiotics can be used to clear the infection and relieve the patients of the symptoms. Antihistamines can be used in cases where allergies are the cause of post-nasal drip. In cases where GORD is the cause, antacids and proton pump inhibitors can be used to control the reflux that is causing the mucus buildup. Although these medications do not address the underlying issue, they can alleviate symptoms when other treatments have not been effective.²

Summary

As discussed here, the causes and links of nasal congestion and post-nasal drip can be complicated. It is important to consider the cause of the congestion and post-nasal drip to understand the links and to find the best treatments. Common causes include infections, allergens, irritants, medications, and certain medical conditions. Often these factors overlap, leading to both nasal congestion and post-nasal drip. Early management is important to avoid complications and long-term impacts such as loss of sleep and chronic sore throat. Decongestants, antihistamines, and steroid nasal sprays can be used to treat nasal congestion by lowering inflammation and improving airflow. Saline sprays and steam inhalation are examples of home therapies that may be beneficial. Antibiotics could be used to cure bacterial infections in post-nasal drip, while antacids, antihistamines, and mucus-thinning drugs could treat allergies, GORD, and symptoms.  If you have persistent symptoms of nasal congestion or post-nasal drip, please seek medical attention from a GP or pharmacist.