The common cold is a benign self-limited syndrome representing a group of diseases caused by members of several families of viruses. It is the most frequent acute illness in the United States and throughout the industrialized world . The term "common cold" refers to a mild upper respiratory viral infection involving, to variable degrees, nasal congestion and discharge (rhinorrhea), sneezing, sore throat, cough, low-grade fever, headache, and malaise. The common cold is a separate and distinct entity, distinguishable from influenza, bacterial pharyngitis, acute bronchitis, acute bacterial sinusitis, allergic rhinitis, and pertussis.
The common cold is associated with an enormous economic burden as assessed by lost productivity and expenditures for treatment . Data extrapolated from a United States telephone survey conducted between 2000 to 2001 suggest that about 500 million non-influenza viral respiratory infections occur yearly, resulting in estimated direct costs of $17 billion and indirect costs of $22.5 billion annually .
The average incidence of the common cold is five to seven episodes per year in preschool children, and two to three per year by adulthood. Annual absences due to colds from school and work in the United States caused 26 and 23 million lost days, respectively . Colds account for 40 percent of all time lost from jobs among employed people . (See "The common cold in children: Clinical features and diagnosis" and "The common cold in children: Treatment and prevention".)
Tens of millions of research dollars have been spent on ways to prevent and shorten the course of the common cold. Although extensive, published reports on treatment of the common cold often suffer from methodological flaws: inconsistent definitions of disease, different measured symptom outcomes, mixing of subjective and objective findings, and variable age ranges . This results in important inconsistencies in reported findings.
Treatment and prevention for the common cold are reviewed here. The epidemiology and clinical manifestations of colds are discussed separately (see "The common cold in adults: Diagnosis and clinical features"). Specific viruses that cause colds are discussed in more detail separately.