Health Knowledgebase

The Common Cold

14th December, 2008 - Posted by Andy -

INTRODUCTION

A cold is an infection that affects the upper respiratory tract - the nose, throat, sinuses (small spaces in the skull behind the eyes and nose), trachea (the main airway that runs to the lungs), larynx (voice box) and bronchial tubes (the airways in the lungs).

Colds are very common. They occur mainly during the winter months, although cold weather itself is not a cause of colds. Children tend to have more colds than adults. This is because adults have built up immunity against some of the viruses that cause colds. On average, adults have between two and four colds a year, while children may have as many as eight or ten.

SYMPTOMS
The symptoms of a cold usually begin 2-3 days after you become infected, and last for 2-14 days. Most people recover from a cold within a week. You are most contagious when you have the sneezing, runny nose and cough that are the first signs of a cold developing. The symptoms of a cold can include:

- Sneezing, a blocked nose
- A runny nose (rhinorrhoea), beginning with clear fluid (mucus) that often becomes a thicker, yellow/green fluid after 2-3 days
- Sore throat, pain when swallowing,
- Mild fever (a high temperature between 37-38.3°C or 98.6-101.0°F),
- Mild earache,
- Tiredness
- Headache, and coughing.

The symptoms of a cold tend to be worse during the first 2-3 days and then ease over the next few days. Some colds can last up to two weeks.
Some people refer to a bad cold as flu (influenza). However, although a bad cold can make you feel very ill, flu is a different condition and the viruses that cause flu are different from those that cause colds. The symptoms of a cold tend to develop over a couple of days, whereas the symptoms of flu have a more abrupt onset, often developing over a matter of hours.

CAUSES
Colds are caused by viruses; there are more than two hundred different viruses that can cause a cold - the most common belong to one of two groups - the rhinoviruses and coronaviruses and can be spread in several ways. If you have a cold and you sneeze, cough or speak, tiny droplets of fluid containing the cold virus are launched into the air. If these are breathed in by someone else then they may become infected. Similarly, colds can also spread through direct and indirect contact. If you have a cold and you touch your nose or eyes and then touch someone else, you may pass the virus on to them. Alternatively, if you touch an object such as a door handle or telephone, the virus may be transferred to the object. If someone touches the object a short time later and then touches their mouth, nose or eyes, they may become infected

Viruses that cause a cold attack the lining of the nose and throat, making these areas become inflamed. As they become inflamed they begin producing more mucus, resulting in a runny nose and sneezing. Colds can be spread in several ways. If you have a cold and you sneeze, cough or speak, tiny droplets of fluid containing the cold virus are launched into the air. If these are breathed in by someone else then they may become infected.

Colds can also spread through direct and indirect contact. If you have a cold and you touch your nose or eyes and then touch someone else, you may pass the virus on to them. Alternatively, if you touch an object such as a door handle or telephone, the virus may be transferred to the object. If someone touches the object a short time later and then touches their mouth, nose or eyes, they may become infected.

TREATMENT
Normally you can treat the symptoms of a common cold at home. There is no cure for a cold and antibiotics are not prescribed because antibiotics do not work against viruses. An exception may be if your cold leads to complications such as sinusitis, ear infection, or tonsillitis, or if you have chronic bronchitis. In these cases, your GP may prescribe you antibiotics. If you are concerned about your baby, or an elderly person or you have a long-term illness such as a chest condition, you should also arrange to see your GP or phone NHS Direct on 0845 46 47 for an assessment.

If you have difficulty breathing or you develop chest pain, you should see your GP urgently. If you have acute sinus pain or ear pain originating in middle ear or your symptoms have lasted more than two weeks, you should see your GP or phone NHS direct for an assessment. Otherwise you can treat all your symptoms at home.

To relieve the symptoms of a cold, the following self-care advice may be helpful:

- Drink plenty of non alcoholic fluids to keep yourself hydrated - this is especially important for children. Water is best, but warm drinks can be soothing,
- Try to rest and avoid strenuous activity,
- Keep the room at a comfortable temperature, but make sure that fresh air is circulating,
- A cough medicine may help to soothe a ticklish or dry cough. Over the counter products available from your local pharmacist are often sold as combined remedies for treating a cough and cold. Preparations may contain several ingredients and so you should always follow the manufacturer’s instructions to make sure you take the best dose for your symptoms,
- Smoke irritates the nose and throat. Try to avoid being around people who smoke and avoid smoke-filled environments like pubs or clubs. If you are a smoker, try to smoke as little as possible while you are feeling unwell,
- Raising the head of your bed slightly by placing a pillow under the mattress can help reduce coughing at night.

Try to reduce the risk of spreading colds to others by covering your mouth when you cough or sneeze and making sure that you wash your hands regularly. Dispose of used tissues immediately.

Steam inhalation (where you place a towel over your head over a bowl of hot water) can help relieve congestion. The steam may help to loosen mucus and make it easier to clear by blowing your nose. If they are added to the water, some ingredients - such as menthol, eucalyptus, camphor, thymol or pine oil - can make it feel as if the passageways in your nose are clearing.

You should take care to avoid getting steam in your eyes as this can burn. Steam inhalation is not advised for children because of the risk of scalding. Instead, a child may benefit from sitting in a hot, steamy bathroom.

Decongestants can be taken by mouth (oral decongestants) or used as a spray in your nose (nasal decongestants). They work by reducing the swelling in the passageways of your nose and help to ease breathing.
Oral decongestants can cause a rise in blood pressure and heart rate, leading to a feeling of being more alert. Therefore if you take over the counter decongestants at bedtime, you may have problems sleeping at night. Oral decongestants such as pseudoephedrine, phenylpropanolamine and phenylephrine are used in many over-the-counter cold remedies.

Oral decongestants may interact with some antidepressants and beta-blockers. If you are taking either of these medicines you should check with your GP or pharmacist before taking oral decongestants. If you have high blood pressure, heart problems or glaucoma you should also check with your GP before using an oral decongestant.

Nasal decongestants work specifically on the nose and are usually safe for adults and older children to use. Nasal decongestants such as oxymetazoline, xylometazoline, phenylephrine and ephedrine are applied directly to the inside of the nose. They are available as nose drops or sprays.

Nasal decongestants should not be used for more than 5-7 days as using them for longer than this can actually make your congestion worse. If you are taking a type of antidepressant called a monoamine oxidase inhibitors, or MAOI, you should not use nasal decongestants. Babies may find feeding difficult if they have a blocked nose. Saline (salt water) nose drops can help if used just before feeding. They are available from pharmacies. If this does not work, ephedrine nose drops can be bought over-the-counter at the pharmacist for babies over 3 months. These should not be used for more than 3-4 days and there is little evidence that they are better than saline drops on their own.

Antihistamines can help to ease the symptoms of a cold because one of the side effects of some antihistamines is that they can help dry up mucus. Examples of antihistamines used in cold remedies are chlorpheniramine, brompheniramine and triprolidine. Doctors don’t usually recommend taking an antihistamine alone to help ease cold symptoms. However, antihistamines are often used in cold medicines along with a painkiller or an oral decongestant.

Antihistamines may cause drowsiness, dry mouth, constipation, difficulty passing urine, or blurred vision. They may also interact with other drugs that cause drowsiness, such as alcohol and some antidepressants and could lead to problems for people with glaucoma or prostate problems. You should check with a pharmacist or your GP before taking cold remedies containing antihistamines.

Paracetamol, ibuprofen or aspirin can reduce fever and act as painkillers (for children use children’s liquid paracetamol). You should always follow the manufacturer’s instructions for the correct dose. You should not take ibuprofen if you have a history of stomach ulcer, indigestion, asthma, or kidney disease. . Aspirin should not be taken by children under 16 years of age or women who are breastfeeding. If painkillers are considered essential during pregnancy, then paracetamol is the painkiller of choice.

PREVENTION
As so many different viruses can cause the common cold, no vaccination against it has yet been developed. However, if you have a cold there are some things you can do to help prevent it from spreading:

- Wash your hands regularly and properly, especially after touching your nose or mouth and before handling food,
- Always sneeze and cough into tissues. This should help prevent the virus-containing droplets from your nose and mouth entering the air where they can infect others. Throw away used tissues immediately and then wash your hands,
- Do not share cups or kitchen utensils with others. Use your own cup, plates and cutlery.

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[Sources: NIH, NHS direct]
[Compiled 12.09.08]