The common cold
is a viral infectious disease that infects the upper respiratory system. It is also known as acute viral rhinopharyngitis
, or acute coryza
. Being the most common infectious disease in humans, the cold is mainly caused by coronaviruses or rhinoviruses.
The human body can never build up resistance to all the viruses that can
cause the common cold. That is why colds are so common and recurring.
According to the CDC (Centers for Disease Control and Prevention)
kindergarten children get an average of 12 colds per year, compared to
adolescents and adults who catch about seven per year.
Experts say that going out when it is cold does not have any effect on
the risk of catching a cold or spreading one. Antibiotics do not cure a
cold or speed up recovery.
According to Medilexicon's medical dictionary
, a common cold virus is "any
of the numerous strains of virus etiologically associated with the
common cold, chiefly the rhinoviruses, but also strains of adenovirus,
coxsackievirus, echovirus, and parainfluenza virus."
What are the signs and symptoms of a cold?
A symptom is something the patient feels or reports, while a sign is
something other people, including a doctor may detect. Pain could be an
example of a symptom, while a rash could be a sign.
The body reacting to the cold virus is mainly what brings about the
symptoms. A release of chemicals is triggered, making the blood vessels
leak, causing the mucous glands to work harder.
The most common symptoms of a cold are:
- Dry throat
- Sore throat
- Mild fever
- Hoarse voice
- Blocked nose
- Mild headache
The rarer symptoms are:
- Muscle aches
- Pink eye
- Reduction in appetite
- Extreme exhaustion
Approximately 25% of people do not suffer any symptoms when infected
with the cold virus; perhaps because their immune system reacts
differently to the virus. Sometimes bacteria can infect the ears or
sinuses - this is known as a secondary bacterial infection - and can be
treated with antibiotics.
What causes a cold?
The common cold can be caused by more than 200 different viruses. Up to
50% of colds are caused by rhinoviruses, other cold causing viruses are:
- Human parainfluenza virus
- Coronavriuses adenovirus
- Human respiratory syncytial virus
When the viruses manage to overpower the body's immune system infection
occurs. The first line of defense is mucus, which is produced in the
nose and throat by the mucus glands. This mucus traps anything inhaled,
such as dust, viruses and bacteria. Mucus is a slippery fluid that the
membranes of the nose, mouth, throat and vagina produce.
When the mucus is penetrated by the virus which then enters a cell, the
virus takes control of the element of the cell which makes protein. It
uses this element to manufacture more viruses, these viruses then attack
Are there any complications of the common cold?
Being infected with the common cold can lead to the following complications:
- Acute Bronchitis - This is when the bronchi in the lungs are
inflamed as a result of either a bacterial or viral infection.
Antibiotics can only be used to treat this if the infection is
bacterial; if it is viral it is common just to treat the symptoms until
the infection goes away with time. A sample of the sputum may be taken
and examined under a microscope to determine what the levels of bacteria
are. Symptoms include wheezing, shortness of breath, coughing and
- Pneumonia - Again this is a condition where the lungs are
inflamed, but this time is due to the alveoli filling with fluid.
Pneumonia can be caused by bacteria or viruses. However, the common cold
virus does not cause pneumonia. If pneumonia occurred as a complication
of a cold the most likely pathogen would be bacterial. The patient will
be prescribed antibiotics. Symptoms include chest pain, cough, an
elevated body temperature, and breathing difficulties.
- Acute Bacterial Sinusitis - This is when bacteria infect the
paranasal sinuses. Nasal and oral decongestants can be used as
treatment; however antibiotics are required both to treat the condition
and to prevent further infection which could lead to other conditions
such as bacterial meningitis. Symptoms include headache, aching of the
sinuses and nasal discharge.
Other complications that the common cold can lead to are:
- Otitis media
- Strep throat
People with the following conditions can be vulnerable to the common
cold and should take measures to avoid catching it as it can worsen
How can a cold be prevented?
- Chronic obstructive pulmonary disease (COPD) - This includes
both emphysema and chronic bronchitis. The Common Cold can exacerbate
emphysema or chronic bronchitis symptoms, leading to increased coughing
and shortness of breath. Sometimes a bacterial infection can occur which
can lead to fever, and the patient will be prescribed antibiotics.
- Asthma - Asthma attacks can be caused by a cold, especially in children.
As there are so many cold causing viruses, it has been difficult for
scientists to develop a vaccine. However there are some precautions that
can be taken to help avoid catching the common cold, these are:
How is a cold treated?
- Avoid close contact with someone infected with a cold.
- Eat lots of vitamin-rich fruit and vegetables regularly so that your immune system remains strong.
- When sneezing or coughing make sure it is done into a tissue. Discard the tissue carefully and wash your hands.
- If you sneeze into your hands make sure you wash them with soap and water immediately.
- If you have no tissues or a handkerchief cough into the inside (crook) of your elbow rather than your hands.
- Wash your hands regularly; cold viruses can be transmitted from one person to another by touch.
- Keep surfaces in your home clean - especially in the kitchen or bathroom.
- Avoid touching your face especially your nose and mouth.
Unfortunately, both antibiotics and antiviral medications are
ineffective against most viruses that cause the common cold. A cold
normally lasts up to ten days; however some symptoms do stay as long as
Although there is no real way of treating or curing the common cold, the
following measures may help ease the symptoms:
What is the difference between a cold and flu?
- Drink plenty of fluids and keep well hydrated, being dehydrated when infected with a cold can make you feel worse.
- Get plenty of bed rest, it is important to get as much sleep/rest as
possible when infected as the body's immune system is fighting off the
- Take aspirin, paracetamol or ibuprofen to relieve headache or fever. Do not give aspirin to children under the age of 16.
- Some people find that inhaling steam helps ease the symptoms of nasal congestion.
As symptoms can sometimes be quite similar, it may be difficult to know
whether you have the flu or a bad cold. Generally, flu symptoms are felt
sooner than cold symptoms. Flu symptoms are also more intense.
People with the flu feel weak and tired for up to two or three weeks. As
the fever comes and goes they will have periods of chills and sweats
(cold sweats). Their muscles will ache, and they will have a runny or
bunged-up nose, headache and sore throat.
Below is a list of symptoms that can or cannot be experienced when being infected with the common cold or flu:
- Flu symptoms
- Headache - common flu symptom, can be quite severe.
- Tiredness and weakness - common and can last a few weeks.
- Extreme tiredness - common early on, and can be severe.
- Aches and pains - yes and usually severe.
- Temperature/Fever - yes ranging from 39⁰C/102⁰F to 40⁰C/104⁰F
- Sneezing - occasionally
- Stuffed up / runny nose - quite common.
- Coughing - quite typical of flu, can be harsh.
- Dry/Sore Throat - frequent.
Treatment is often with antivirals. Immunization (flu shot, or flu mist) is available to aid in prevention. Please see "What is Flu? What is Influenza? What are the Symptoms of Flu?" for further information.
- Cold Symptoms
- Headache - uncommon, but possible.
- Tiredness and weakness - occasionally, but milder than with flu.
- Extreme tiredness - uncommon.
- Aches and pains - much milder than with flu.
- Temperature/Fever - unusual.
- Sneezing - a common cold symptom
- Stuffed up/runny nose - quite common.
- Coughing - occasionally, but not as severe as with flu.
- Dry/Sore Throat - common
Treatment only provides temporary relief of symptoms, and good hygiene is the best prevention.