The causes of chronic cough are very varied and are related to different systems.

In this article we explain what are the irritants and other factors that can cause coughing.

Because the irritants and other factors trigger cough?

There are many irritants and triggers that can cause or worsen coughs. These include:

• Irritant substances
  • Tobacco smoke and its derivatives, both active and passive
  • Air pollution
  • Chemicals such as solvents, paints or cleaning products
  • Perfumes and air fresheners with strong odors
• Allergens
  • house dust
  • Dust mites
  • Animal dander
  • Pollens
  • Mold

The mechanism by which inhalation of these substances and allergens produces cough is:

• There are sensory receptors in the respiratory tract that detect chemical, mechanical, or thermal irritants. When these receptors are activated, they send a signal to the brain's cough center to trigger the cough reflex.
• Substances such as tobacco smoke irritate the respiratory mucosa, causing inflammation and the activation of receptors.
• Allergens such as dust or pollen produce an immune response that releases histamine and other inflammatory substances, causing bronchospasm and airway hypersensitivity.
• Continued exposure to irritants can cause chronic inflammation, sensitizing cough receptors, which are activated by mild stimuli.

Other triggers

• Physical exercise

Cough can be induced by exercise, due to a phenomenon called exercise-induced bronchoconstriction or exercise-induced asthma.

During intense exercise, there's a greater tendency to breathe through the mouth rather than the nose, which makes the air enter colder and drier. This cools and dries the airways, triggering a local inflammatory response and bronchoconstriction, which leads to coughing, along with other symptoms such as shortness of breath, a feeling of tightness, and wheezing.

Cold, dry, or polluted air can irritate the airways during exercise, triggering the cough reflex.

This is exacerbated after a respiratory infection, in which the bronchi become more sensitive, meaning that exercise can trigger frequent coughing episodes.

Exercise increases abdominal pressure, promoting gastroesophageal reflux, which irritates the throat and causes coughing.

• Changes in temperature

In the event of sudden temperature changes, the respiratory system may react by causing coughing.

When we pass from warm to cold air, or vice versa, the blood vessels in the airways constrict rapidly to conserve body heat. This vasoconstriction can irritate the throat and bronchial tubes, activating cough receptors.

Cold, dry air can irritate the mucous membranes of the airways, triggering a reflex cough.

• Stress and anxiety

Stress and anxiety can cause a type of cough called “psychogenic cough”Stress hormones, such as adrenaline, are released when we feel anxious because our body enters a state of heightened alert. This can manifest physically with a dry, persistent cough. The cough can be aggravated by muscle tension in the chest and throat caused by the body's normal response to stress.

Anxiety and stress can cause hyperventilation (breathing more rapidly and deeply than normal), which irritates and dries out the lining of the airways. This reaction causes coughing.

Anxiety leads to coughing, and coughing exacerbates anxiety by being an annoying situation that is difficult to control, creating a vicious cycle that is difficult to break.

• Laughter and talk

Laughter-induced coughing occurs as a result of a complex interaction between several physiological systems, involving the respiratory and nervous systems. When we laugh, we expel a sudden burst of air, which, as it passes through the airways at high speed, causes irritation, stimulating the sensory nerves lining the airways. These nerves send signals to the brain, initiating the cough reflex to eliminate the irritation and the perceived sensation of obstruction.

In people with respiratory conditions such as asthma and COPD, the airways are more sensitive and likely to react to laughter.

In addition, when we laugh, our diaphragm and abdominal muscles contract, which can cause gastroesophageal reflux disease.

When we speak for long periods of time or loudly, our throat dries out, which stimulates cough receptors. In people with gastroesophageal reflux disease (GERD), where stomach acids irritate the larynx, or in those with inflamed airways due to a respiratory infection or allergy, or in those who frequently experience anxiety, this process worsens and coughs appear earlier.

Author: Eva Maroto

References:

1. https://www.msdmanuals.com/es/hogar/trastornos-del-pulm%C3%B3n-y-las-v%C3%ADas-respiratorias/enfermedades-pulmonares-ambientales-y-ocupacionales/introducci%C3%B3n-a-las-enfermedades-pulmonares-ambientales-y-profesionales
2. Delgado Romero, J. Exercise-induced asthma or bronchospasm. Respiratory in Primary Care. Issue 1. April 2022 
3. https://nolahagasdetos.mx/por-que-los-cambios-de-temperatura-generan-tos/ 
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