The common cold is a viral infection of your nose and throat (upper respiratory tract). It's usually harmless, although it might not feel that way. Many types of viruses can cause a common cold.
Children younger than six are at greatest risk of colds, but healthy adults can also expect to have two or three colds annually.
Most people recover from a common cold in a week or 10 days. Symptoms might last longer in people who smoke. If symptoms don't improve, see your doctor.
Symptoms
Symptoms of a common cold usually appear one to three days after exposure to a cold-causing virus. Signs and symptoms, which can vary from person to person, might include:
Runny or stuffy nose
Sore throat
Cough
Congestion
Slight body aches or a mild headache
Sneezing
Low-grade fever
Generally feeling unwell (malaise)
The discharge from your nose may become thicker and yellow or green in color as a common cold runs its course. This isn't an indication of a bacterial infection.
When to see a doctor
For adults — seek medical attention if you have:
Fever greater than 101.3 F (38.5 C)
Fever lasting five days or more or returning after a fever-free period
Shortness of breath
Wheezing
Severe sore throat, headache or sinus pain
For children — in general, your child doesn't need to see the doctor for a common cold. But seek medical attention right away if your child has any of the following:
Fever of 100.4 F (38 C) in newborns up to 12 weeks
Rising fever or fever lasting more than two days in a child of any age
Symptoms that worsen or fail to improve
Severe symptoms, such as headache or cough
Wheezing
Ear pain
Extreme fussiness
Unusual drowsiness
Lack of appetite
Causes
Although many types of viruses can cause a common cold, rhinoviruses are the most common culprit.
A cold virus enters your body through your mouth, eyes or nose. The virus can spread through droplets in the air when someone who is sick coughs, sneezes or talks.
It also spreads by hand-to-hand contact with someone who has a cold or by sharing contaminated objects, such as utensils, towels, toys or telephones. If you touch your eyes, nose or mouth after such contact or exposure, you're likely to catch a cold.
Risk factors
These factors can increase your chances of getting a cold:
Age. Children younger than six are at greatest risk of colds, especially if they spend time in child-care settings.
