What is Common Cold, its causes and signs & symptoms?

Common cold is a viral infection caused by number of viruses.It is mostly a droplet infection spread through coughing and sneezing. The disease is often harmless and self limiting i.e. get well on their own with a week symptoms like coughing, sore throat or headache which require symptomatic treatment. The common cold is a most common infectious disease involving adults, children and infants.

Causes of common cold

Common cold is a viral infection of upper respiratory tract caused by following viruses:
• Rhino virus (30 to 50%)
• Corona virus (10 to 15%)
• Influenza virus (5 to 15%)
• Human Para influenza viruses
• Human respiratory syncytial virus
• Adeno viruses
• Entero viruses and
• Metapheumo virus

Risk factors of the common cold

Following are the conditions by which risk of disease is increased:
• By touching nose, eyes or mouth with contaminate fingers.

• Come in close contact with infected person or spending time in close area with an infected person by droplet infection through coughing and sneezing.

• Duration of disease may extend by about 3 days in smokers.

• Common cold is a seasonal disease occurs more frequently in winter. It is believed by some one that it is partly due to change in behaviors such as time spent indoors by which people get infected due to close contact to other people, rather than the exposure to cold temperature.

• Sleep more than 8 hours per night minimizes the risk of infection 3 times in case of rhinovirus exposure.

• Low humidity increases the viral transmission ate i.e. dry air causes evaporation of water, resulting small viral droplets to disperse and stay in the air longer.

• Persons with strong immune systems are more prone to develop symptomatic colds. This is because the symptoms of a cold are directly due to the strong immune response to the virus and not the virus itself.

• About 25% of adults have less active immune systems and get infected with the viruses because of relatively weak immunological response results no significant or identifiable symptoms. These people are asymptomatic carriers and can spread the virus (disease) to others.

• Boosting the immune system increases cold symptoms because strong immune responses cause cold symptoms.

• It has been studied that exposure to the cold causes cold symptoms in about 10%.

Signs and Symptoms of common cold

Typically symptoms of common cold start two to three days after exposure to infection. Signs and symptoms of common cold vary depending on the type of virus responsible for infection of disease which is as follows:
• Nasal congestion
• Runny nose
• Sore throat/Scratchy throat
• Cough and cold
• Hoarseness of voice
• Conjunctivitis (pink eye)
• Headache
• Low grade fever
• Muscle ache
• Loss of appetite
• shivering
• Fatigue
Signs and symptoms of common cold in infants and children are similar to those of adults. The disease may begin with a runny nose with clear nasal discharge, which may become yellowish or greenish in colour after two to three days. Infants and children may become more irritable with decreased appetite. Young children often have fever (100-102 degree C).
Symptoms of common cold usually subsides within a week (7 days)but in some cases symptoms lasts for 2-3 weeks.

Progression (Manifestation) of common cold

• Virus multiplication begins from 2 to 6 hours after initial contact.
• Symptoms begin to develop 2-5 days after initial infection but sometimes occur in as little as 10 hours.

• Peak symptoms occur 2-3 days after first symptom onset while influenza symptom onset is constant and immediate.

• Symptoms of common cold usually subside within a week (7 days) but in some cases symptoms lasts for 2-3 weeks.

• In children cough lasts for more than 10 days in 35-40 % of cases and continues for more than 25 days in 10%.

• The first symptom of upper respiratory tract viral infection is often sore throat or scratchy throat.

• Other symptoms are sneezing, runny nose and congestion. Sometimes these are accompanied by body ache, malaise, headache, weakness or loss of appetite.

• Cough and fever mostly indicate influenza rather than upper respiratory tract viral infection.

• Symptoms of common cold may be more severe in infants and young children.

• Upper respiratory tract viral infection may be more severe in smokers.

Infectious period of common cold

There are so many viruses that can cause common cold but rhinovirus virus is highly infectious during first three days of symptoms and less infectious after those three days. Common cold is usually not infectious after the first week.

Complications of common cold

• Common cold is the most common trigger of asthma symptoms in children with asthma.
• Sinusitis
• Ear infection
• Pneumonia
• Bronchitis

Prevention of common cold

Common cold can be prevented by following ways:
• Most effective prevention for the common cold is keeping away yourself from infected person and place.

• Regular personal hygiene like hand washing is recommended to reduce the spread of cold virus and other pathogens by direct contact. Hand washing with soap and water removes the virus particles from the hands.

• Alcohol based sanitizers kill viruses, but less effective in respiratory tract infection than preventing gastrointestinal diseases.

• Common cold is caused by virus and not by bacteria so regular soap is as affective as antibacterial soaps for removing the virus from skin and other surfaces.
• Though aqueous iodine removes the cold virus on human skin but iodine is not used as virucidal because it discolours and dries the skin.

• Use paper towels (napkins) instead of sharing cloth towels.

• Strong immune system helps your body in preventing infection.

Ways to improve your immune system

• Avoid smoking especially 2nd hand smoking (sharing one cigarette with others).

• Avoid use of antibiotics: Too much use of antibiotics may lead to antibiotic resistance.

• Breast feed: Mother's milk is well known to protect against respiratory tract infections in children. Those children who are not breast fed get about 5 times more ear infections than those who are breast fed.

• Water intake: Fluid intake improves your immune system to work properly.

• Get proper enough sleep: Not getting enough sleep makes you more prone to fall sick.

• Eat curdled milk: It contains active beneficial bacteria that help to prevent common cold.

Time to call your Doctor in case of common cold

Call your health provider when-
• Breathing becomes difficult
• Symptoms get worsen or do not improve after one week (7 days).

Treatment of common cold

• Like other viral infections, common cold is self limiting disease which takes its own time to cure.

• There is no specific treatment of disease. Only symptomatic medical treatment is recommended.

• Get proper plenty of rest and drink plenty of fluids.

• Antibiotics are not recommended. If common cold do not improve after 10 to 14 days then your doctor may prescribe antibiotics.

• Antiviral drugs are not helpful in reducing common cold symptoms.

• Alternative treatment used in common cold to minimise the symptoms and enhance the immune system are vitamin C, Zinc, chicken soup and Echinacea.

Prognosis of common cold

The disease is self limiting and usually subsides in 7 to 10 days. Prognosis of common cold is good.

Other names of common cold

• Cold
• Acute coryza
• Nasopharyngitis
• Acute viral rhinopharyngitis


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