Although it is now one of the most dreaded symptoms, health experts say a cough is actually a vital player in the body’s defense against disease. Coughing expels mucus, microbes, and foreign particles from the respiratory tract, protecting the lungs from infection and inflammation.
According to Dr Moses Semweya, dry cough is a cough where no phlegm or mucus is produced (known as non-productive). Dry coughs are often caused by viral illnesses such as colds and flu, but they can also be caused by allergies or throat irritants.
“Basically, with a dry cough one feels something tickly on the throat and they are forced to keep clearing it,” the doctor explains.
This type of cough can be irritating but depending on its severity, people often keep off seeking medical attention and it eventually clears on its own.
“A cough which is a result of the common cold or the flu tends to last a week or two and clears up within about three weeks. But one caused by other viral infections is persistent and may last for up to two months,” says Dr Semweya. He notes that coughs that last longer than two months are described as chronic and are usually a sign of an underlying problem.
Most patients suffering from a dry cough tend to cough more at night according to Dr Sewmweya because when they lie down, stomach contents particularly stomach acid, can reflux out of the stomach and cause cough. Asthma can be due to cold, dry air often present at night. Post-nasal drip can also cause more coughing when you lie flat.
Other patients, especially children sometimes end up vomiting when they cough severely. “When coughing triggers vomiting, you should seek medical attention because it might be a sign of a cough from a severe cold or a severe string of coughs from some irritant that might get worse if left untreated,” he notes.
Specific treatment for a dry cough will depend on the cause of the cough.
A dry cough is often the result of a viral illness, such as a cold or influenza (the flu), or COVID-19 the disease caused by SARS-CoV-2 – the novel coronavirus; or a post-viral, or post-infective, cough (cough that persists for weeks after a viral illness).
Some people start coughing when they breathe very dry, heated air. This can be caused by environmental irritation or allergies.
Chronic dry coughs are usually caused by irritation from cigarette smoke, environmental irritants, allergies, postnasal drip, or asthma. Several chronic lung diseases also cause a dry, hacking cough. Some people cough out of habit for no clear reason.
However, a dry cough may be a result of other problems, such as asthma, gastro-oesophageal reflux, smoking, allergic rhinitis (hay fever) due to inhaling substances you are allergic to, such as pollen, dust or pet dander; post-nasal drip (the drainage of mucus secretions from the nose or sinuses down the back of the throat – also known as upper airway cough syndrome); laryngitis (inflammation of the larynx, also known as the voice box).
Other causes include whooping cough; obstructive sleep apnoea and snoring, habit cough (a cough that is only present in the daytime and not caused by illness it most often affects school-going children), an inhaled foreign body (such as food or other objects accidently being inhaled usually in babies and small children), certain types of lung disease known as interstitial lung disease; or a side effect from a medicine (for example, cough is a possible side effect of most ACE inhibitors – often prescribed for high blood pressure).
Other, less common, causes of a dry cough include heart failure; pulmonary embolism (a blood clot in the lungs); or lung cancer.
A dry cough can be aggravated by breathing cold, dry air, air pollution, inhaled irritants such as dust or smoke, exposure to tobacco smoke; excessive use of your voice; or a change in temperature.
When to see a doctor
Dr Edward Kukungulu, a general practitioner, recommends seeking medical attention when the individual starts to cough up blood, has associated chest pain or fever or severe headache or ear pain.
He adds that a dry cough is contagious depending on the cause.
“When the cough is a result of mucus dripping from the back of the nose into the throat and the person coughs next to someone they will infect them with the germs found in the droplets expelled,” he explains.
Coughs caused by smoking (smoker’s cough) and allergies are, however, not contagious.
“If you have a dry cough as part of a cold or infection, it can be contagious. Take precautions, such as more frequent hand-washing and covering your mouth when you cough,” the doctor advises.
Some dry coughs can be treated from home if the symptoms are not linked to a condition requiring a doctor’s care. Here are several at-home treatments you can try.
Oral demulcents: Demulcents soothe the pharynx and relieve irritation. You can try a cough syrup containing sugar and glycerol or add honey and lemon to warm water.
Cough suppressants: Cough drops and cough syrups can suppress the urge to cough.
Increase fluids: Drink more fluids, especially water, to keep the pharynx coated and reduce any tickle.
Salt water: If the dry cough is caused by an irritated throat, gargling with salt water can help. Salt removes water from mucous membrane cells, reducing swelling.
Avoid triggers: These triggers, such as cold and dry air, pollution, cigarette smoke, excessive talking or yelling exacerbate dry coughs from asthma.