Cough

Overview

Coughing is a reflex action started by stimulation of sensory nerves in the lining of the respiratory passages, by a something that should not be there.

When a person coughs, there is a short intake of breath and the larynx (the voice box) closes momentarily. The abdominal and chest muscles used for breathing contract, which in turn increases the pressure needed to drive air out the lungs when the larynx re-opens.

The resulting blast of air comes out at high speed, scrubbing and clearing the airway of dust, dirt or excessive secretions. Coughing is a common symptom when the airways are ‘tight’, as in asthma.

The cough reflex is a vital part of the body’s defence mechanisms. Normally, the lungs and the lower respiratory passages are sterile. If dust or dirt gets into the lungs, they could become a breeding ground for bacteria and cause pneumonia or infection in the breathing tubes.

How we get coughs

A foreign body or irritant substances

Cough can be caused by breathing in dust particles, smoke or some other irritant substance in the air, or when a piece of food goes down the wrong way.

Bacterial/viral infections of the lung

Common cold, acute bronchitis, pneumonia, whooping cough and croup, are all infections of the lung which cause cough.

Disease or serious illness

Gastro-oesophageal reflux, post-nasal drip, pneumonia, acute heart failure, lung cancer or pulmonary embolism (a clot in the blood vessels of the lung) may all cause cough.

Medication

Some people taking angiotensin converting enzyme inhibitors (ACE inhibitors), used in heart disease, may develop a dry cough.

Symptoms

Dry cough

Occurs because the throat and upper airways becomes inflamed, it is non-productive (phlegm is not produced). Dry coughs are usually felt in the throat as a tickle, which sets off the coughing.

Conditions producing a dry cough would include:-

Asthma (especially at night and on exertion)

Gastro-oesophageal reflux (especially after eating and on lying down)

A foreign body

Smoking

Common cold/viral infection

Cough due to ACE inhibitors (see above)

Post-nasal drip

Chesty cough

Can be either productive (phlegm is produced) due to extra mucus produced as a response to infection or non-productive due to infection causing the lung passageways to swell. If a cough feels chesty but is non- productive, this should be described as a chesty cough; phlegm may be present but is not loose enough to be coughed up.

Conditions producing a chesty cough would include:-

Heart failure

Bacterial/viral infection

Pneumonia

Risk Factors

Age

In otherwise healthy people age is the predominant risk factor for chest infections.

The elderly, especially the frail, the malnourished and those who cannot keep warm are susceptible to chest infection. Such infections may make aged patients take to their beds where they may develop pneumonia.

Infants are more likely to develop chest infections because they haven’t developed resistance to most of the viruses that cause them.

Asthma

Although wheezing (a tight noise when breathing out) is the classic symptom of asthma, many children’s major symptom is a cough. The cough is dry (non-productive) and often sounds tight. It tends to get worse at night, with exercise, or after being exposed to a trigger (e.g. cigarette smoke, animal hair, or house dust). Children with asthma often have a prominent cough when they catch a cold.

Some children with asthma have wheezing with no cough; some have cough with no audible wheezing; and some have both.

If a child with asthma has difficulty speaking or sleeping because of wheezing, cough, or shortness of breath, it is important to contact the doctor immediately.

Smoking

Smoking will exacerbate a cough and can cause coughing since it is irritant to the lungs. One in three long-term smokers develop chronic cough.

Gasto-oesophageal reflux

Stomach acid coming back up the gullet and spilling over into the windpipe can cause dry cough.(See our article on heartburn and indigestion)

Chronic or frequent sinus infections

Drainage from nose or sinuses (post-nasal drip) can cause a dry cough.

Heart failure

The cough is normally chesty with the sputum produced often described as “pink and frothy”. An individual suffering from heart failure would also be breathless (especially in bed and during the night) and have swollen ankles. Chest infections are more likely in individuals suffering from heart failure due to the build of fluids in the lung.

Living or working in close quarters

Viral and bacterial infections spread easily anywhere people gather – childcare centres, classrooms, offices, prisons and military installations.

Complications

Children, the elderly (especially those that are frail, malnourished or suffering from other illnesses), asthmatics and smokers have an increased chance of suffering from complications due to a bacterial or viral chest infection.

A cough caused by a bacterial infection or a viral infection which has weakened immune response and resulted in a bacterial infection, leads to the production of green or brown mucus. If the mucus has not cleared after seven to ten days and particularly if you feel unwell you may need to take antibiotics to clear the infection. Coughs left untreated may also lead to the development of pneumonia.

When to seek medical advice

It is difficult to give a hard and fast list of when you should see your doctor, but below is a list which covers the main things to look out for:-

* phlegm which is green, yellow or rusty colour, or containing blood
* coughing up blood
* cough lasting longer than two weeks
* shortness of breath
* chest pain on breathing or coughing
* unexpected loss of weight
* regular night time cough
* harsh barking cough in children (croup)
* whooping sound when breathing in after a fit of coughing (whooping cough)

Treatment

The choice of treatment for cough depends on the type of cough. Suppressants are effective in treating a dry unproductive cough, while expectorants are used in the treatment of a productive cough. Many cold and flu preparations contain several ingredients some of which may cause problems when given with certain drugs or taken by patients with certain illnesses. Very few preparations are suitable for children under two years of age and pregnant women. Therefore it is always important to talk to your pharmacist when buying any cough preparation over-the-counter.

Cough Suppressants (e.g. codeine, pholcodeine, dextromethorphan)

Pholcodeine and codeine are both very effective cough suppressants. A cough medicine containing pholcodeine is less likely to cause drowsiness and constipation than codeine so would be a better choice. Codeine preparations may not be as readily available from your pharmacist as they are subject to abuse.

Dextromethorphan would not be as effective as pholcodeine in suppressing cough but has few side effects and is contained in many cough medicines.

Cough expectorants (e.g. guaiphenesin, carbocisteine, ammonium salts)

The aim of all cough expectorants is to aid the propulsion of phlegm from the lungs. It is thought that carbosisteine may also help to liquefy phlegm and therefore aid its removal from the lungs.

Cough medicines may also contain antihistamines (See our article on cold antihistamines). These may be useful in cough medicines for dry coughs as they act as a cough suppressant and also dry secretions (useful for a dry cough caused by post-nasal drip in a head cold). Many antihistamines in cough preparations may cause drowsiness so are unsuitable for those who are driving or operating machinery. Antihistamines have teratogenic effects and should therefore never be used in pregnancy. They are also unsuitable for some other people so always discuss your medication and current health problems with a pharmacist before purchasing them.

Other ingredients may include decongestants (See our article on cold decongestants). Menthol and eucalyptus may also be included and these ingredients would give some short-term relief from congestion.

Brand name of preparations available and their ingredients

To relieve a chesty cough

Benylin Clear Action

Pulmoclase

Exputex syrups contain expectorant carbocisteine. This liquefies phlegm and therefore aids its expulsion from the lungs. They do not cause drowsiness.

Robitussin Chesty Cough

Benylin Chesty Coughs (non-drowsy)/Children’s Chesty Coughs

Tixylix Chesty Cough (for children) contains expectorant guaiphenesin. This aids the expulsion of phlegm from the lungs. They do not cause drowsiness.

Casacol contains expectorant guaiphenesin and methoxyphenamine, an ammonium salt that helps open out the airways to make breathing easier. It does not cause drowsiness.

To relieve a chesty cough with congestion

Robitussin Chesty Cough with Congestion Syrup

Benylin Dual Action Chesty Syrup both preparations contain expectorant guaiphenesin and decongestant pseudoephedrine. The decongestant in these preparations will relieve congestion and the expectorant will aid the expulsion of phlegm from the lungs. They do not cause drowsiness.

To relieve a dry cough

Pholcodine syrup contains pholcodine, a very effective cough suppressant. It does not cause drowsiness.

Benylin Dry Coughs Non-Drowsy Syrup

Robitussin Dry Cough

Delsym contain dextromethorphan, a cough suppressant. They do not cause drowsiness.

Glycerin Honey and Lemon is a demulcent and is useful for soothing sore throat with dry cough in those that are unable to take other cough syrups (especially pregnancy and for babies). It does not cause drowsiness

To relieve congestion with dry cough

Benylin Dual Action Dry Syrup contains decongestant pseudoephedrine, antihistamine triprolidine and cough suppressant dextromethorphan. This preparation is useful to relieve congestion as both the antihistamine and decongestant will be effective in this process. The antihistamine and cough suppressant also relieve dry cough caused by post-nasal drip. The antihistamine in this product may cause drowsiness.

Benylin Dry Coughs contains antihistamine diphenhydramine, cough suppressant

dextromethorphan and levomenthol. Dextromethorphan is a cough suppressant and antihistamine diphenhydramine also acts to suppress dry coughs. Diphenhydramine also relieves congestion and levomenthol would also give some relief. The antihistamine in this product may cause drowsiness.

Benylin Cough Medicine Original Formula/Benylin Children’s Dry Coughs contains antihistamine diphenhydramine and levomenthol. Diphenhydramine acts to suppress dry cough and it and levomenthol would provide relief from nasal congestion.

Prevention

Smokers who get recurrent chest infections should seriously consider stopping smoking (See our article on smoking cessation). Although when stopping smoking, a cough may initially become worse as the cleaning action of the cilia (small finger-like projections in the airways that help move matter out of the lungs) is re-established during the first few days. However, giving up cigarettes will lessen or abolish smokers’ cough in 94 per cent of people within four weeks.(See our article on smoking cessation)

Asthmatics must always use their preventative inhalers and medication as prescribed by the doctor, even at times when they are feeling well. Keeping asthma symptoms under control reduces the risk of asthma attacks and chest infections.

Those on angiotensin converting enzyme inhibitors and feel their cough coincided with their commencement on the medication should seek the advice of their doctor. Alternative medication can be prescribed that will not cause this side-effect.

For others, especially those who are at increased risk of developing chest infections (infants, the elderly and those with heart failure); it is sensible to take common sense precautions when somebody you are in contact with has a common cold or is coughing.

Wash your hands.

Clean your hands frequently and teach your children the importance of hand washing.

Keep things clean

Keep kitchen and bathroom countertops clean, especially when someone in your family has a common cold. Wash your child’s toys after play if your child has a common cold.

Use tissues.

Always sneeze and cough into tissues. Discard used tissues right away.

Be a little selfish.

Don’t share drinking glasses or utensils with other family members. Use your own glass or disposable cups when you or someone else is ill.

Stop smoking

And avoid being around those who do.

Steer clear of colds and coughs

Avoid close, prolonged contact with anyone who has a common cold or cough.

Consider possible allergens in your home

Do you have animals? You or your family may be allergic to them and that is what is causing certain illnesses, including cough. Think about cleaning products that you use, if they are making you cough and giving you a sore throat stop using them.

Choose your child-care centre carefully

Look for a child-care setting with sound hygiene practices and clear policies about keeping ill children at home.

Self Care

Stop smoking
If you are determined to continue smoking, at least stop for the duration of the cough to give the lungs an opportunity to try to clear the infection.

Steam inhalations
These can be very useful, particularly in productive (chesty) coughs. The steam helps to liquefy lung secretions and the warm, moist air is comforting. Menthol and eucalyptus can also help reduce congestion in a cough associated with a cold and one teaspoonful of it should be added to a pint of hot (but not boiling water). A cloth or towel can be put over the head to trap the steam.

Increase fluid intake
Keeping a high fluid intake helps to hydrate the lungs and hot drinks can have a soothing effect. If you have a cough or a cold, increase your fluid intake by around two litres a day.