Chronic or prolonged cough – What you need to know

Frustrated with the constant hacking and throat irritation that wouldn’t go away for months? You are likely not alone. Chronic or prolonged cough is an annoying symptom that can have a significant impact on the quality of life of the sufferer. This is one of the most common symptom seen by Dr Gan, an ENT Specialist in Singapore with a subspecialty training in nose & sinuses.

What is cough?

Cough is a protective reflex that results in expulsion of air from your lung to clear the upper airway of foreign bodies, mucous and irritants. When cough is persistent, it is often a symptom of an underlying condition. The most common way to classify cough is based on its duration as follows:

Acute – Less than 3 weeks duration
Subacute – 3-8 weeks duration
Chronic- More than 8 weeks duration

What is the cause of my persistent cough?

Acute cough (< 3 weeks duration) is most commonly due to a viral upper respiratory tract infection (e.g. common cold). It often resolves on its own without the need for medications or a visit to the doctor.

Subacute and chronic cough or often called “prolonged cough” as the approach to these two groups of cough are similar. The table below is a list of potential causes of chronic cough (not meant to be exhaustive):

A study in a restructured hospital in Singapore has shown that the most common cause of cough in the local context are postnasal drip, acid reflux from the stomach, and Asthma. This is in line with international studies that have shown that more than 90% of chronic cough are due to these 3 conditions.

What is Postnasal Drip?

Postnasal drip refers to the feeling of mucous stuck at the back of your nose and throat. The cause is often due to over production of mucous (e.g. in Rhinitis (“sensitive nose”)) or thick mucous from Sinusitis (infection of the sinuses). Mucous from these nasal conditions can irritate and cause swelling of the voice box (medically known as laryngitis). The voice box can also be swollen because of acid irritation from the stomach (medically known as laryngopharngeal reflux aka LPR). A swollen voice box can cause symptoms like throat itchiness, frequent throat clearing, hoarse voice, sore throat, feeling of something stuck and a cough.

What do I expect when I see an ENT Specialist for chronic cough?

Your ENT Specialist will likely take thorough medical history and perform a complete ear, nose and throat examination. It is also important to inform your doctor of your regular medications as some medications can cause cough. For a complete assessment of your cough, your ENT Specialist will likely recommend a nasoendoscopy (nose scope done in the clinic under local anaesthesia). A nasoendoscopy allows the assessment of the nasal cavity, outflow tract of the sinuses as well as the throat and voice box. It is a relatively painless procedure that takes only a few minutes to perform and can often be tolerated in children as young as four years old. If you have symptoms suggestive of a lung condition (e.g shortness of breath, wheezing etc), a chest X-ray may be ordered. Your ENT Specialist may also refer you to a Lung Specialist to have a lung function test done if he/she suspects that you may have Asthma or a lung condition.

How is chronic cough treated?

This depends on the underlying cause.: Common treatments include:

•  Nasal steroid sprays and antihistamines for Rhinitis
•  Oral antibiotics, nasal steroid sprays and a nasal douche (“salt wash of the nose/sinuses”) for Sinusitis
•  Acid suppressant medications and lifestyle modifications for patients with Laryngopharngeal Reflux
•  Inhaled asthma drugs for Asthma
•  Stop smoking for smoker’s cough
•  Stop certain medications (e.g. ACE inhibitors for high blood pressure, NSAIDs etc ) for drug-induced cough

What are the warning signs of a cough?

You should visit your doctor if you have:

• Cough lasting longer than 2-3 weeks that is not related to any recent cold/chest infections
• Thick or coloured phlegm
• Extreme tiredness
• Shortness of breath
• Blood in your phlegm
• High fever
• Loss of weight and appetite

When should I take cough suppressants?

Sometimes the cause of the cough may not be found (e.g. Idiopathic cough or “cough hypersensitivity syndrome”), your doctor may give you a course of cough suppressants to keep you comfortable. Having said that, there is no evidence that cough suppressants are effective and may have potential side effects if taken long term. Studies have shown that 2 teaspoons of honey a day (taken at bedtime) is as effective as dextromethorphan, one of the most commonly used cough suppressant. Honey may reduce night time coughing and improve sleep in children. However, due to a rare but potentially serious risk of bacterial infection (called botulism), honey should never be given to a child younger than 1 year old.

For common questions on cough and cold, do check out my Q&A sessions on DxD

Best wishes,

Dr Gan Eng Cern
ENT Specialist Singapore