How to Care for a Dry Cough
Coughing is a defence mechanism to protect us from irritants in our throats and airways. When an irritant is present, it stimulates nerves in the respiratory tract, sending a message to our brains. The brain then signals the muscles of the abdomen and diaphragm to give a strong push of air to your lungs to expel the irritant.
Difference between a wet cough and dry cough
Puzzled when a health professional asks you whether you are having a wet cough or a dry cough? The conditions can be distinguished by observing the presence or absence of phlegm, rather than the subjective feeling in your throat.
A wet cough, also known as productive cough, is coughing with phlegm. It forces out secretions from the respiratory tract that, if retained, could impair ventilation and the lungs' ability to fight infection. The colour of the secretions may give an indication to the causative agent, e.g. clear phlegm could be due to bronchitis and yellowish phlegm could be due to bacterial infection.
A dry cough, also known as non-productive cough or "hacking" cough, is coughing without phlegm.
Should a dry cough be suppressed?
As there is no phlegm (which traps irritants) to be cleared when you are having a dry cough, coughing would serve no useful purpose. Therefore, dry coughs may be suppressed with an antitussive (medication to suppress cough), if desired.
Dry cough remedies
There are two groups of antitussives: centrally acting agents and peripheral acting agents.
Centrally acting agents
Centrally acting medications act on the brain to increase the cough threshold and they include codeine, dextromethorphan, pholcodine, diphenhydramine and promethazine. Purchase of these medicines requires a pharmacist’s consultation. The efficacies of these medicines are similar and they differ in their side effect profiles.
Codeine, diphenhydramine and promethazine may cause drowsiness and they should not be taken with alcohol. In addition, the person should exercise caution when driving or operating heavy machinery after taking these medicines. Pholcodine causes drowsiness to a lesser extent while dextromethorphan causes drowsiness in some rare cases.
Besides drowsiness, codeine may cause constipation and may not be suitable for elderly or people who have difficulties passing motion. It may also cause dependence in some people and thus, it is advisable to try other cough suppressants before starting with codeine.
The Health Science Authority has advised against the use of promethazine in children less than 2 years of age. For children 2 to 6 years old. the drug is to be taken with caution. Nonetheless, if your child has been taking promethazine under a doctor’s instruction or supervision, the benefits outweigh the risks.
Peripheral acting agents
Peripheral acting medicines create a soothing effect and they include camphor and menthol. These medicines can be bought over the counter.
Camphor and menthol ointments are to be rubbed thickly onto the throat or to the chest up to three times daily. However, they are to be used with caution for people with sensitive skin. Parents should guard against accidental ingestion of large amounts of such ointments as it may pose a serious threat to the health of young children.
Menthol lozenges soothe the throat and suppress cough. As most of these lozenges contain sugar, people with diabetes are recommended to choose sugar-free versions.
When to see a doctor
One should not self-treat in any of the following circumstances:
- the dry cough has persisted for more than one week;
- the child is less than 2 years old;
- the person experiences shortness of breath; or
- the person has a history of asthma or other lung disease.
These symptoms signal a more complicated issue underlying dry cough, so medical attention is required.