Sneezing, coughing and a blocked or runny nose are all symptoms of the most common disease in humans. We all suffer from colds from time to time, but on average children get twice as many colds each year as adults, accounting for 22 million lost school days in the US and most GP visits during certain months in the UK.
What causes the common cold?
The common cold, also known as coryza, is the result of an infection by one of many types of virus, most commonly rhinovirus, coronavirus and respiratory syncytial virus. Over 100 different members of a virus family can cause a cold, with new variants appearing regularly. This makes it almost impossible to create a vaccine.
What are the symptoms?
The virus invades and kills cells lining the nose and throat, causing:
* watery, yellow mucous in the nose
* a blocked nose
* sneezing
* a sore throat
* a cough.
As the immune system battles the virus it creates chemicals that can cause general signs of infection, such as a mild temperature and a headache, although these are often absent.
How is it spread?
The virus is usually spread by direct contact, such as on hands that have wiped noses, or by droplet spread, with the virus sneezed or coughed out and then inhaled by somebody else.
The cold is particularly common among children in daycare and nurseries as they tend to play and learn in close proximity, increasing opportunities for cross-infection. Good hygiene, sneezing into a tissue and frequent, thorough hand washing can help to prevent its spread, but it is almost impossible to prevent all infections.
Once the immune system has fought off a cold, it remembers that virus and can kill it more quickly next time. This means you are unlikely to catch a cold from someone who caught it off you, and if so the illness will be much shorter and milder than the first time. This is also one reason why adults have fewer colds than children.
Is there a cure?
There is no cure or vaccine for the common cold. Antibiotics work only against bacteria, so they are of no use against a cold. As all medications carry a small risk of side effects, taking antibiotics 'just in case' may cause more harm than good.
Treatment is aimed at making the symptoms more bearable, and paracetamol or ibuprofen can bring down temperature and relieve headaches. Remember that adult doses are too large for most children, and never give a medicine to a child against parent or nursery policy.
There is no evidence that decongestants are effective against colds, but many are available over the counter. There is also no clear evidence that Vitamin C or echinacea shorten the duration of a cold or improve symptoms.
Is a cold the same as the flu?
No. Influenza is caused by a different set of viruses and results in more unpleasant symptoms. The flu may have some features of the cold, but also includes muscle aches and pains, a severe headache and a lack of energy.
Should a child with a cold be at nursery?
If a child feels ill or under the weather staying at home may be best.
However, if she is in no discomfort there is no reason not to be at nursery as the cold is a mild infection. Again, encourage frequent handwashing and tissue use to minimise the risk of infection.
When should I be worried?
If a cold is associated with any of the following, medical advice should be sought:
* earache
* facial pain
* severe headache
* rash
* noisy breathing
Dr Chris Russell is based at Guys Hospital in London
Further information
* www.nhsdirect. nhs.uk
* www.bbc.co.uk/ health
* www.cardiff.ac.uk/ biosi/associates/ cold/info.html
IS A COLD THE SAME AS THE FLU?
COLD SYMPTOMS FLU SYMPTOMS
Gradual onset Sudden onset
Low or no fever High fever
Mild/no headache Moderate/severe headache
Stuffy, runny nose Clear nose
Sneezing Sometimes sneezing
Mild cough Cough, often becoming severe
Slight aches and pains Severe aches and pains
Sore throat Sometimes a sore throat
Normal energy level Extreme exhaustion
Normal appetite Decreased appetite
