What Causes a Cough?

A young male pharmacists advising a young female customer on appropriate treatments for her cough across the counter of his pharmacy.

Exploring the causes of cough

Cough is a common symptom of colds and flu,1,2 and in some cases can be severe.3,4 Here we take a closer look at the various cough causes.

Graphic image of a person’s respiratory system, including the nose, mouth and lungs

Coughing is a natural and necessary reflex

Coughing is a physiological defensive response of the respiratory system in an attempt to keep the airways clear.

As sensory cough receptors contained in the lungs and airways are stimulated by irritants, signals are sent to the brain’s cough centre and cerebral cortex and then onwards to the brain stem. From here, effector neurons communicate with the diaphragm and intercostal muscles to contract.5 The subsequent coordinated action of the larynx and abdominal muscles force air from the larynx at speed, causing the typical coughing motion.5,6

  • Classification of Cough

    Coughing man graphic image – the side profile of a man with particles coming from his mouth

    Identifying the type of cough

    Coughs may be acute or chronic, and wet or dry. As appropriate treatment is guided by the type of cough, it is important to classify the patient’s cough.

    Acute coughs last for less than 3 weeks,7 with the sub-acute classification covering coughs with durations between 3 to 8 weeks. A chronic cough lasts for longer than 8 weeks.8

    A dry cough, also known as an unproductive cough, involves little or no mucus. Coughing fits may be unexpected and unpredictable, triggered by a ticklish, burning sensation(or irritation) in the throat. A wet, or productive, cough, is a purposeful, intentional cough aimed at loosening mucus stuck in the chest.8-10

  • Triggers

    Cough triggers

    Different classes of cough are associated with different causes. The list of cough causes is extensive but includes:

    Mature male adult coughing while holding his chest

    Upper respiratory tract infections

    This is the main source of acute or sub-acute coughs, and includes both viral and bacterial infections, the most frequent agent being rhinovirus.11

    Signs and symptoms icon – graphic image of a person blowing their nose into a tissue


    Allergic rhinitis may cause acute cough.

    Young woman with long wavy blonde hair stands in front of a female brunette pharmacist in a pharmacy coughing

    Retronasal drip/upper airway cough syndrome

    Along with bronchial asthma and gastroesophageal reflux, these conditions constitute around 80% of chronic cough causes.11

  • Other causes

    Young woman with long brunette hair wearing a stripy top coughing into her fist

    Other serious causes of cough

    Other conditions that should be considered in acute cough include pneumonia, lung cancer, and tuberculosis.11

Wildfire burns through a forest, scorching the ground black and filling the air with grey smoke

The effects of climate change on cough

It is now widely accepted that climate change is occurring due to global warming. As a result, global average temperatures are rising, and this also has an impact on communities around the world.

Climate change was deemed a public health crisis by the American Medical Association in 2022, due to the consequences on general health that could result from a warming planet.12

As extreme wildfires have increased in frequency and ferocity, in part due to climate change, this has also led to an increase in harmful particles such as PM2.5 being emitted, and also, inhaled by humans.13,14

Particles of this size are much smaller than human hair, dust, pollen and mould, even human red blood cells.15 PM2.5 is a concern when inhaled at very high levels as the particles are a small size, meaning they can be inhaled easily, deep into the lungs, and in some cases can enter the bloodstream.

Inhalation can lead to both short- and long-term health issues including but not limited to coughing, nose, throat, eye and lung irritation, asthma, cardiovascular damage and even increased mortality for those with lung and/or heart disease.13,14

As a healthcare professional, some of your patients with asthma or COPD, may be more susceptible to inhaling PM 2.5 particles, if for instance, they live near busy roads or in areas with high levels of traffic. Understanding more about your patients can help you offer them better treatment methods.16,17

Panadol Cold & Flu – Trusted Formulations for Relief from Cold and Flu Symptoms

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