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. The common cold – traditionally also called a chill – is one of several viral infections that cause respiratory symptoms and systemic illness. Others include PNEUMONIA and GASTROENTERITIS. 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 (see SINUS), 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.
Treatment Symptomatic treatment with ANTIPYRETICS and ANALGESICS 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.
Most colds result from breathing-in virus-containing droplets that have been coughed or sneezed into the atmosphere, though the virus can also be picked up from hand-to-hand contact or from articles such as hand towels. Prevention is, therefore, diﬃcult, given the high infectivity of the viruses. No scientiﬁcally proven, generally applicable preventive measures have yet been devised, but the incidence of the infection falls from about seven to eight years – schoolchildren may catch as many as eight colds annually – to old age, the elderly having few colds. So far, despite much research, no eﬀective vaccines have been produced.