What is a dry cough?
A dry cough, also called unproductive cough, is a type of cough that is tickly and without phlegm; the thick mucus-like substance that comes up when we cough.
Types of cough
Coughing is an involuntary and important action that helps to protect our lungs and respiratory system against irritants. A cough is defined by its characteristics (wet cough, dry cough or chesty cough), duration or cause.
As reported in this paper1, there are three classifications for cough and they are:
- Acute cough: If your cough lasts less than 3 weeks, it is termed acute. This type of cough typically clears up on its own.
- Subacute cough: A cough that lasts about 3 - 8 weeks is a subacute cough. This type of cough is also known as post-infection cough, because it usually occurs after an acute cough, although it can also precede the onset of chronic cough.
- Chronic cough: When the cough lasts over 8 weeks from its onset, it is a chronic cough. Chronic cough usually requires treatment to get rid of or manage it, but if it does not respond to treatment, then it is a chronic refractory cough.
Causes of dry cough
Dry cough can be caused by various things ranging from common cold to bacterial infection or allergies. In rare cases, it could be a sign of a heart attack.
Asthma is a respiratory disease where the airways become narrow from swelling as a result of being sensitive to certain triggers. Some of these triggers are mould or damp, genetics, weather, pollen, dust mites, stress, emotion or laughter.
The cause of asthma is unknown. Genetics, modern hygiene standards and pollution have been suggested as causes, but there is not enough evidence to prove this.2 It is best to get advice on handling your triggers once you take note of them.
Symptoms of asthma include wheezing, shortness of breath and cough. Some people have a cough as their only symptom, known as Cough Variant Asthma (CVA)3. CVA can either be a dry cough or a wet cough.
An allergy is the reaction your body has to a particular food or substance, known as allergens.4 These can trigger reactions such as coughing or itchiness. They are very common and mostly common in children. Some allergies can be outgrown while others may be present throughout our lifetime and sometimes, we develop allergies to things we were initially okay with.
Common allergens include tree pollen, dust mites, some medications, sea food, mould, household chemicals, nuts, latex and mould.
Postnasal drip, also called sinusitis, is a condition where the cavities surrounding the nasal passage get swollen due to exposure to bacteria5, allergens or environmental irritants such as gas, cigarette smoke or fumes. Postnasal drip can also be brought on by eating spicy food or a change in weather conditions. Colder weather means higher chances of nasal congestion.
A viral infection can be an upper respiratory infection. Flu, sinusitis, laryngitis, common cold, and whooping cough are some examples. It can also be a lower respiratory infection, like bronchiolitis, bronchitis, tuberculosis and pneumonia. COVID-19 affects either the upper or lower respiratory tract. Some diseases, such as whooping cough, bronchial otitis and tuberculosis are less common than others.
Respiratory tract infections are caused when we are exposed to viruses which attack our immune system. The cough typically starts a day or so after exposure. It can start as a dry cough and become productive after some days.1
Cough symptoms from an infection usually resolve within two weeks and include a scratchy or sore throat, chest pain, sneezing, stuffy or runny nose and cough.
Hay fever or allergic rhinitis is caused by post nasal drip and it can result in symptoms like congestion, coughing, sneezing, congestion, as well as itchy nose, eyes and skin.6
Gastroesophageal reflux disease (GERD)
This condition is also known as acid reflux and characterised by symptoms such as indigestion and heartburn. The symptoms of GERD can be triggered by foods that contain high levels of fat or acids.7
Less common causes
Congestive Heart Failure
Congestive heart failure occurs when the heart's ability to pump blood is so greatly reduced that fluid builds up in the blood vessels. This affects the route between the heart and lungs. In this condition, the lungs become abnormally swollen, which results in a reduction in oxygen supply, irritation of the lungs, and coughing. 1
Choking or aspiration occurs when you swallow food or saliva and it goes into the airway, to your lungs, and not the food pipe, into the stomach. As a result of this condition, the lungs become abnormally swollen, which results in a reduction in oxygen supply, irritation of the lungs, and coughing.1
Croup cough is mostly caused by the Parainfluenza virus and occurs in children 5 years or younger, characterised by a barking sound. It is an upper airway infection that prevents breathing.8
Pulmonary diseases are diseases of the lungs. Dry coughs may be a sign of an issue with our pulmonary system. This can be seen in someone who has Pulmonary embolism, a Collapsed Lung, Chronic Obstructive Pulmonary Disease (COPD), Idiopathic pulmonary fibrosis (IPR) or lung cancer. COPD may manifest as a wet or dry cough.1
A dry cough can be the side effect of medication like ACE inhibitors, used in treating blood pressure. This side effect is caused by Bradykinin, a diuretic that helps to remove excess water from the body, open up blood vessels and lower blood pressure.9 The diuretic helps to ease inflammation, but makes the throat sensitive while doing this, increasing the cough reflex.10
Vocal cord dysfunction
This is also known as Irritable Larynx Syndrome. It is a case where there is an abnormal closing of the vocal chord when you breathe in or out. Your vocal cords do not open properly causing the throat to be sensitive.11 It causes discomfort in the throat and the resulting action is a cough or throat clearing. Breathing exercises and speech therapies in addition to medication can help with vocal cord dysfunction.
Is a dry cough an indicator of a serious health problem?
Dry cough is mostly not an indicator of a serious health problem. It could be your body’s defence system helping fight a flu or an infection, or just trying to clear your airways. It is only in rare cases that chronic cough would be an indicator of a serious health problem.
If you have concerns because of discomfort or your cough is persistent without clearing up on its own, you should see your healthcare provider. When accompanied by other symptoms, a chronic cough could be a symptom of Chronic Obstructive Pulmonary Disease (COPD), heart failure or tuberculosis.
Can a dry cough be contagious?
Dry cough can be contagious depending on the cause. If it is caused by a bacteria or virus, it can readily be transmitted to someone else.
For diagnosis, your healthcare provider will ask you questions to know your health history and the history of your cough. You will also be given a physical exam and sent for some tests for further diagnosis.
The American Lung Association12 has a list of information you can prepare in advance to help your healthcare provider with your diagnosis.
During the physical exam, your healthcare provider will check the number of breaths you take and your temperature. They might do a spirometry test, lung function test, order a chest x-ray, check your oxygen levels, or order a chest X-ray or lung function tests if your cough has been persistent.
Most times, you may not have any need to treat your cough as it goes away on its own, such as an acute cough. The symptoms may disappear when you treat the underlying illness or remove the trigger causing them.
There are a wide range of treatment options available if you choose to take or need medication for your cough. These treatments can be done at home, or by taking over-the-counter medicine.
- Cough syrup
- Antihistamines for allergies, if it is an allergic reaction.
- Decongestants like nasal spray
- Antacids for heartburn caused by GERD
- Inhalers and nebulizers for asthma patients
- Antibiotics for bacterial infections
- Cough suppressants, if your cough is without a known cause.
- Drink lots of water to stay hydrated and replenish electrolytes (calcium, potassium, sodium etc) which help to maintain chemical reactions in the body and make it function more efficiently.
- Honey - Taking a spoonful of honey for your cough is almost as effective as taking a cough syrup. Take note that honey should not be given to children less than one year as it can cause botulism13 in babies.
- Cough drops or cough candies
- Use a humidifier to add extra moisture from the air to help soothe your airways and relieve a dry cough. Another way to do this is to do steam inhalation or by taking a hot bath. You could add essential oils like eucalyptus or lavender to your water for this.
- Drink lots of fluid
- Proper hygiene practices like washing your hands regularly, especially before preparing food or eating, after coughing or using the bathroom, help to reduce the transmission of communicable diseases.
- Avoid touching organs with mucus membranes; your nose, mouth, or eyes after being in close contact with people, when possible.
- Try to air out your house, open up the windows at least once a week so there can be ventilation and fresh air can circulate. This works by reducing moisture and the growth of mould.
- If you are allergic to dust or asthmatic, wear a nose covering or mask to reduce the risk of you inhaling them.
- Avoid food and substances you are allergic to.
- If you are sick, cover your mouth with a tissue when you cough or sneeze and dispose of it properly, to prevent spreading it to others.
When to see a doctor
You should see a doctor when you have a persistent dry cough which refuses to go away after 3 weeks. When the dry cough starts getting severe or produces mucus that is either greenish or bloody, or you start experiencing other symptoms such as chest pain, shortness of breath, wheezing, fever, or dizziness, you should also contact a medical professional.
A dry cough with no other symptoms may very well be just a cough that you should not worry about, because in most cases, it is just our body’s way of protecting us. Simple things like increasing fluid intake and taking a rest can help to ease coughing. Drinking water, good hygiene, and letting our homes ventilate often can also reduce our chances of having a dry cough.
It is also important to keep your triggers away if you suffer from an underlying illness such as asthma or gastroesophageal reflux disease.
If you experience a chronic dry cough for more than eight weeks and it is accompanied by other symptoms, you should consult your doctor for diagnosis and treatment.
- Sharma, Sandeep, et al. ‘Cough’. StatPearls, StatPearls Publishing, 2022. PubMed, http://www.ncbi.nlm.nih.gov/books/NBK493221/.
- ‘Asthma - Causes’. Nhs.Uk, 20 Feb. 2018. https://www.nhs.uk/conditions/asthma/causes/.
- Niimi, Akio. ‘Cough and Asthma’. Current Respiratory Medicine Reviews, vol. 7, no. 1, Feb. 2011, pp. 47–54. PubMed Central, https://doi.org/10.2174/157339811794109327.
- ‘Allergies’. Nhs.Uk, 19 Oct. 2017, https://www.nhs.uk/conditions/allergies/.
- MD, Robert H. Shmerling. ‘Treatments for Post-Nasal Drip’. Harvard Health, 13 Apr. 2018, https://www.health.harvard.edu/staying-healthy/treatments-for-post-nasal-drip.
- ‘Hay Fever’. Nhs.Uk, 23 Oct. 2017, https://www.nhs.uk/conditions/hay-fever/.
- Sifrim, D., et al. ‘Weakly Acidic Reflux in Patients with Chronic Unexplained Cough during 24 Hour Pressure, PH, and Impedance Monitoring’. Gut, vol. 54, no. 4, Apr. 2005, pp. 449–54. gut.bmj.com, https://doi.org/10.1136/gut.2004.055418.
- ‘Croup - Symptoms and Causes’. Mayo Clinic, https://www.mayoclinic.org/diseases-conditions/croup/symptoms-causes/syc-20350348. Accessed 22 July 2022.
- Al-Shamlan, Fajer, and Ahmed Z. El-Hashim. ‘Bradykinin Sensitizes the Cough Reflex via a B2 Receptor Dependent Activation of TRPV1 and TRPA1 Channels through Metabolites of Cyclooxygenase and 12-Lipoxygenase’. Respiratory Research, vol. 20, no. 1, June 2019, p. 110. BioMed Central, https://doi.org/10.1186/s12931-019-1060-8.
- Pirahanchi, Yasaman, and Sandeep Sharma. ‘Physiology, Bradykinin’. StatPearls, StatPearls Publishing, 2022. PubMed, http://www.ncbi.nlm.nih.gov/books/NBK537187/.
- ‘Vocal Cord Dysfunction: Treatment, Causes & Diagnosis’. Cleveland Clinic, https://my.clevelandclinic.org/health/diseases/17623-vocal-cord-dysfunction. Accessed 22 July 2022.
- Living With Chronic Cough. https://www.lung.org/lung-health-diseases/lung-disease-lookup/chronic-cough/treating-and-managing. Accessed 22 July 2022.
- Abdulla, C. O., et al. ‘Infant Botulism Following Honey Ingestion’. BMJ Case Reports, vol. 2012, July 2012, p. bcr1120115153. PubMed Central, https://doi.org/10.1136/bcr.11.2011.5153.