An infection by any one of around 200 viruses, with about half the common-cold infections being caused by RHINOVIRUSES. Certain CORONAVIRUSES, ECHOVIRUSES and COXSACKIE viruses are also culprits. Colds are commoner in winter, perhaps because people are more likely to be indoors in close contact with others.
Also called acute coryza or upper respiratory infection, the common cold is characterised by inflammation of any or all of the airways – NOSE, SINUSES, THROAT, LARYNX, TRACHEA and bronchi (see BRONCHUS). Most common, however, is the ‘head cold’, which is confined to the nose and throat, with initial symptoms presenting as a sore throat, runny nose and sneezing. The nasal discharge may become thick and yellow – a sign of secondary bacterial infection – while the patient often develops watery eyes, aching muscles, a cough, headache, listlessness and the shivers. PYREXIA (raised temperature) is usual. Colds can also result in a flare-up of pre-existing conditions, such as asthma, bronchitis or ear infections. Most colds are self-limiting, resolving in a week or ten days, but some patients develop secondary bacterial infections of the SINUSES, middle ear (see EAR), TRACHEA, or LUNGS.
Symptomatic treatment such as ANTIPYRETIC and ANALGESIC drugs is usually sufficient; ANTIBIOTICS should not be taken unless there is definite secondary infection or unless the patient has an existing chest condition which could be worsened by a cold. Cold victims should consult a doctor only if symptoms persist or if they have a pre-existing condition, such as asthma which could be exacerbated by a cold. Although it is commonly believed that infection is passed by airborne droplets, it is also passed by contact – for example, with the hand of a person who has sneezed into their palm or just wiped their nose. Hence, sneezing into one's upper sleeve can protect others.