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.
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.