Clinical Evidence Handbook A Publication of BMJ Publishing Group

Common Cold BRUCE ARROLL, Department of General Practice and Primary Health Care, Auckland, New Zealand

This is one in a series of Transmission of is can affect any part of the mucosa, it is often chapters excerpted from mostly through hand-to-hand contact rather arbitrary whether an upper the Clinical Evidence than droplet spread. Several types of is called a cold or sore Handbook, published by the BMJ Publishing Group, can cause cold symptoms. ( or ), , London, U.K. The medical • Each year, children have up to five colds media, or . Sometimes all information contained and adults have two to three colds, leading areas of the mucosa, simultaneously or at herein is the most accurate available at the date of to time off from school or work and consid- different times, are affected during one ill- publication. More updated erable discomfort. Most symptoms resolve ness. Symptoms include sneezing, and comprehensive infor- within one week, but often persists. (runny nose), , and general . mation on this topic may Nasal and oral reduce nasal In addition to nasal symptoms, one-half of be available in future print editions of the Clinical congestion over three to 10 hours, but we do patients experience , and 40 per- Evidence Handbook, as not know how effective they are for longer- cent experience cough. This review does not well as online at http:// term relief (more than 10 hours). include treatments for persons with acute www.clinicalevidence. do not reduce symptoms over- sinusitis, , or sore throat. One bmj.com (subscription required). Those who all and can cause adverse effects and increase prospective study in the United States (1,246 receive a complimentary resistance. children enrolled at birth) found that chil- print copy of the Clinical • Antibiotics may improve symptoms dren who had frequent colds at two or three Evidence Handbook from after five days compared with years of age were twice as likely to experience United Health Foundation can gain complimentary in persons with nasopharyngeal culture- frequent colds at six years of age, compared online access by register- positive Haemophilus influenzae, Moraxella with children who had infrequent colds at ing on the Web site using catarrhalis, or Streptococcus pneumoniae, but two or three years of age (relative risk = 2.8; the ISBN number of their book. it is difficult to identify which persons may 95% confidence interval, 2.1 to 3.9). have these infections. seems unlikely to reduce the Incidence and Prevalence

This clinical content con- duration or severity of cold symptoms com- Upper respiratory tract infections, nasal con- forms to AAFP criteria for pared with placebo. gestion, throat problems, and cough are evidence-based continu- • We do not know whether gel or responsible for 11 percent of general prac- ing medical education lozenges, , steam inhalation, anal- tice consultations in Australia. Each year, (EB CME). See CME Quiz on page 1343. gesics, or anti-inflammatory drugs reduce children have about five such infections and the duration of symptoms of colds. adults have two or three infections. One A collection of Clinical Evidence Handbook pub- may slightly reduce runny cross-sectional study of Norwegian children lished in AFP is available nose and sneezing, but their overall effect four to five years of age found that 48 percent at http://www.aafp.org/ seems small. Some antihistamines may experienced more than two common colds afp/bmj. cause sedation or arrhythmias. annually. We found insufficient evidence to assess whether decongestants plus antihistamines Etiology and Risk Factors are effective in reducing cold symptoms. Transmission of common cold infections is mostly through hand-to-hand contact, with Definition subsequent passage to the nostrils or eyes— Common colds are defined as upper respira- rather than, as commonly perceived, through tory tract infections that affect the predomi- droplets in the air. Common cold infections nantly nasal part of the respiratory mucosa. are mainly caused by viruses (typically rhi- Because upper respiratory tract infections novirus, but also , respiratory

Downloaded from the American Family Physician Web site at www.aafp.org/afp. Copyright © 2011 American Academy of Family Physicians. For the private, noncommercial use 1390 Americanof one individualFamily Physicianuser of the Web site. All other rights reserved.www.aafp.org/afp Contact [email protected] for copyrightVolume questions 84, and/or Number permission 12 ◆ requests. December 15, 2011 Clinical Evidence Handbook Research Clinical Questions What are the effects of treatments for common cold? essential to Likely to be Antihistamines (may improve runny nose beneficial and sneezing, no significant difference in overall symptoms) Decongestants (norephedrine, family medicine oxymetazoline, or provides short-term [three to 10 hours] relief of congestive symptoms) The Annals of Family Medicine, a peer-reviewed Unknown or anti-inflammatory drugs clinical research journal, is dedicated to advancing effectiveness Decongestants (insufficient evidence to knowledge essential to understanding and improving assess longer-term [more than 10 hours] health and primary care. View the full content online at effects on congestive symptoms) www.AnnFamMed.org, or order your print subscription Decongestants plus antihistamines online or by calling 1-800-274-2237, Ext. 5165. Echinacea Steam inhalation Zinc (intranasal gel or lozenges) Unlikely to be Vitamin C beneficial Likely to be Antibiotics ineffective www.AnnFamMed.org or harmful

syncytial , metapneumovirus, and others). Often, no infecting organism can be identified.

Prognosis Common colds are usually short-lived, lasting a few days, with a few lingering symptoms lasting longer. Symptoms peak within one to three days and generally clear by one week, although cough often persists. Although they cause no mortality or serious morbidity, common colds are responsible for considerable discomfort, lost work, and medical costs.

EDITOR’S NOTE: Norephedrine is called phenylpropanolamine in the United States, where it is no longer available.

SEARCH DATE: January 2010. Author disclosure: Dr. Arroll is on the advisory board for the Pharmac educational seminars, a government-funded pharmaceutical purchasing agency in New Zealand, and is on the primary care committee of the Future Forum, an educational foundation funded by AstraZeneca (United Kingdom). He is the lead author of two studies included in this review. Free online Adapted with permission from Arroll B. Common cold. Clin Evid Hand- access! book. June 2011:521-522. Please visit http://www.clinicalevidence.bmj. com for full text and references. ■ Sponsors: American Academy of Family Physicians, American Board of Family Medicine, Society of Teachers of Family Medicine, Association of Departments of Family Medicine, Association of Family Medicine Residency Directors, North American Primary Care Research Group, College of Family Physicians of Canada

The Annals of Family Medicine is indexed in MEDLINE, MEDLARS, Science Citation Index Expanded, Current Contents/Clinical Medicine, PsycINFO, EMBASE, and CINAHL. Complete text of the journal is available online at http://www.annfammed.org and through various aggregators, including PubMed Central, EBSCO, and MDConsult.

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