The common cold is a viral infection of the nose, throat, and upper airways that causes a runny or stuffy nose, sore throat, sneezing, headache, and coughing. Infection can occur by inhaling infected droplets from coughs or sneezes, or by touching the mouth or nose after contact with a contaminated object or the skin of somebody with infected droplets on his or her skin.
Symptoms usually develop between 1 and 3 days after infection and become worse over about 1 to 2 days. Most colds clear up by themselves within a week or two.
Medical advice should be sought if a cold lasts for more than about 3 weeks, if symptoms worsen, or if other symptoms develop.
Occasionally, a cold may be complicated by a bacterial infection, causing, for example, acute bronchitis , sinusitis, or a middle ear infection (otitis media). In such cases, medical treatment is needed
