Introduction

Post-nasal drip, also known as upper airway cough syndrome, occurs when an irritant in your nose or sinuses triggers excessive mucus production. This mucus gets trapped and builds up in the back of your nose eventually dripping down your throat. This can cause coughing, sore throat, and other allergy symptoms. It is important to recognise this condition early to avoid chronic cough. 

Normally, in a disease-free person, the nose and sinuses produce mucus. The mucus has many important functions such as: clearing the airway, moisturising the inhaled air and reducing the chances of infections. Post-nasal drip is a condition when due to an underlying cause, there is excess mucus production.¹

In this article, we will discuss post-nasal drip in depth.

Causes

There are various causes of post-nasal drip, some of which are listed below:

• Allergy 
• Influenza (flu)
• Bacterial infections
• Cold, dry air
• Sinus inflammation (sinusitis) 
• Spicy food
• Pregnancy
• Chronic acid reflux disease (GERD, gastroesophageal reflux disease)
• Certain medications
• Rhinitis (allergic and non-allergic rhinitis) 
• Cold
• Rhinosinusitis⁵

Symptoms

Even though some doctors consider post-nasal drip as a symptom instead of a condition, in this article we will discuss it as a condition. Here is a list of possible symptoms of post-nasal drip:

• Sore throat (pain in the throat leading to difficulty swallowing)
• The feeling of mucus draining down the throat
• Hoarseness of voice
• Frequent swallowing of saliva
• Recurring urge to clear the throat
• Bad breath
• Cough
• Nausea and vomiting 
• Sneezing 
• Ear pain
• Red eyes
• Runny nose

Diagnosis

Patient history

The doctor will ask the patient specific questions to determine the underlying cause of the post-nasal drip. This is an important step as it helps them recognise allergens, find out family history and correlate information.

Physical examination

During physical examination, positive findings are noted down to help find the cause of the condition. The ears, nose and throat are examined superficially with a torch at times.

Endoscopy

It is also called rhinolaryngoscopy. A special camera is put inside the nose and throat to check for post-nasal drip, which is a common and painless examination. It is done to evaluate structural problems that can cause post-nasal drip like deviated septums, nasal polyps, and masses. 

Allergen panels

If the patient has signs of an allergy, the doctor will advise them to go for an allergen test to find out the substance they are allergic to. The allergen is then avoided and specific medications are given to the patient. There are many allergen tests, the most common ones are:

• Allergy skin testing
• Fluorescence enzyme immunoassay 
• Nasal provocation test

Immunodeficiency tests

These are performed if the person has a history of recurrent infections. It checks if the person’s immune system is working properly.

Radiography

These imaging techniques can help visualise the internal structure of the ear, nose and throat, including the paranasal sinuses.

• X-Ray
• Computed tomography (CT)
• Magnetic resonance imaging (MRI)

Other tests

Your healthcare provider will ask the patient to go for other tests as well if it is necessary. This may include:

• Biopsy
• Total serum IgE
• Total blood eosinophil count
• Nasal cytology^{1, 3, 4} 

Treatment options

Symptomatic relief

• Humidifiers are used to moisten the surrounding air so that dryness doesn’t trigger mucus production. 
• Adequate water intake helps with the sore throat.
• In case of allergies, allergens should be avoided. If it is seasonal, the doors and windows must be kept closed and the use of air purifiers may help many people. Face masks can be worn whilst being outdoors to further reduce exposure to allergens.
• Nasal saline sprays can help reduce symptoms by irrigating the nose. 

Medications

Medications given depend on the cause of post-nasal drip. Here are some common drugs used for specific causes of post-nasal drip. 

Antihistamines

These drugs are used for allergies by reducing mucus secretion. Examples of these drugs are Cetirizine, Levocetirizine, Fexofenadine, Loratadine, Desloratadine, Chlorpheniramine, and Diphenhydramine. Some of these are available over the counter but it is better to consult the healthcare provider before taking them. 

Leukotriene receptor antagonists 

Leukotriene receptor antagonists are used as an alternative to antihistamines for allergies. Examples include Montelukast. The side effects of these drugs are minimal.

Expectorants

These drugs make the mucus thinner, thereby increasing mucus clearance. 

Nasal corticosteroids

They are used when all other medications aren’t giving the desired results. They are used for multiple causes of post-nasal drip including allergies. They’re given via the nose in the form of a spray. Commonly used drugs are Beclomethasone, Budesonide, Fluticasone, Ciclesonide, Triamcinolone, and Mometasone. 

Allergen Immunotherapy

Immunotherapy is one of the new ways allergy is treated. It is used for severe, chronic allergies. Examples are grass pollen allergen extract, Timothy grass pollen allergen extract, ragweed allergen extract, and house dust mite immunotherapy. They’re generally more expensive than other treatments. 

Systemic corticosteroids

These drugs are used for severe allergy cases for a short duration of time (generally 5-7 days). The most commonly given systemic corticosteroid is prednisolone.

Antibiotics

They’re given to patients with an upper respiratory tract infection (ear, nose, throat, or sinuses). Antibiotics are prescribed by your healthcare provider. 

Other drugs

Many medications are given to reduce symptoms, such as antiemetics for nausea and vomiting. The patient should consult a healthcare provider so that all their needs are met. Patients with GERD (Gastroesophageal reflux disease) should take regular medications to avoid flare-ups. 

Surgical interventions

In case of a nasal foreign body, nasal obstruction, adenoids, tumours, or nasal polyps, the doctor will need to perform surgical interventions to provide relief. One common surgery used for allergic rhinitis is Turbinoplasty. Septoplasty is a common surgery if the cause is a deviated nasal septum.^{3 4 5}

When to seek medical attention

When symptoms persist for a long time despite home remedies, one should contact a doctor for medical advice. Severe discomfort or difficulty breathing, fever, blood in nasal discharge and change in the colour of mucus are some alarming symptoms that need to be discussed urgently. In most cases, post-nasal drip isn’t caused by a serious condition. Patients should contact their healthcare provider for personalised advice according to their cases.^{3 4, 5} 

Conclusion

Postnasal drip, also known as upper airway cough syndrome, arises from nasal or sinus irritation triggering excessive mucus production. This surplus mucus accumulates at the back of the nose, leading to symptoms like cough, sore throat, and more. This article delves into the condition, covering its causes, symptoms, diagnosis, and treatment options. Causes include allergies, influenza, bacterial infections, dry air, sinus inflammation, and more. Symptoms encompass sore throat, hoarseness, cough, and other discomforts. Diagnosis involves patient history, physical examination, endoscopy, allergen panels, and various tests like X-rays and CT scans. Treatment options include symptomatic relief, medications (antihistamines, corticosteroids), and, in severe cases, surgical interventions. Recognizing when to seek medical attention is crucial, especially if symptoms persist or severe discomfort arises. Individualised advice from a healthcare provider is recommended for comprehensive management.