Common Cold (Nonspecific Infections of the Upper Respiratory Tract)

Definition, Etiology, Pathogenesis Top

The term common cold (viral rhinopharyngitis; viral rhinosinusitis) refers to signs and symptoms associated with a mucosal inflammation of the nasal cavities, pharynx, and sinuses usually caused by an acute viral infection.

1. Etiologic agents: Over 20 types and 250 subtypes of viruses, most commonly rhinoviruses (30%-50%), coronaviruses (10%-15%), influenza and parainfluenza viruses, respiratory syncytial virus, adenoviruses, and enteroviruses (eg, coxsackievirus). Occasionally, bacteria such as Mycoplasma pneumonia, Chlamydophila pneumonia, and Bordetella pertussis can cause symptoms of the common cold. The respiratory viruses penetrate the upper respiratory epithelium and begin to replicate. This induces a local inflammatory response, which leads to vasodilation (edema, exudate), an increase in mucus secretion, and sometimes also to a damage to epithelial cells.

2. Reservoir and transmission: The reservoir for the etiologic agents of the common cold are sick individuals; it is transmitted mainly by contact with droplets of infected respiratory secretions but may also involve a direct contact with a sick person or an enteral route, depending on the type of the virus.

3. Incubation and contagious period: The incubation period varies between viruses but is generally from 1 to 4 days. Virus shedding is highest during the first 3 days of the illness but may continue for up to 2 weeks after the onset of the disease.

Clinical Features Top

The common cold usually has a mild onset. The signs and symptoms may include some or all of the following:

1) Sore throat.

2) Rhinitis: Initially clear nasal discharge and postnasal drip, followed by nasal congestion, olfactory impairment, and sneezing. Nasal discharge may subsequently become thicker, greenish, or even purulent, although this does not generally indicate a bacterial etiology.

3) Cough: Initially dry, later may become productive from postnasal drip.

4) Chills and fever (usually low grade), although body temperature is frequently normal. Fever is more common in children and is an infrequent symptom in adults with the common cold. Fever >38 degrees Celsius may be indicative of influenza.

5) Malaise, headache, lethargy, and myalgia may occur. Myalgia is more typical of influenza infection than of the common cold.

6) Pharyngitis: Erythema and inflammatory papules on the posterior pharyngeal wall, sometimes papules or vesicles on the soft palate, discharge on the posterior pharyngeal wall.

7) Conjunctivitis (adenoviruses) and rash (adenoviruses, enteroviruses) may be present.

Patients with the common cold recover spontaneously. The signs and symptoms peak within 2 to 3 days and usually resolve after 7 to 10 days. In a portion of patients, some symptoms may persist for 2 to 3 weeks or longer.

The significant overlap in symptoms associated with the common cold and influenza may make it difficult to distinguish between the two infections. The common cold is generally a milder illness. Runny or stuffed nose and sneezing are more frequently associated with the common cold, whereas a sudden onset of fever, myalgia, intense exhaustion, and cough are more likely associated with influenza.

Diagnosis Top

Diagnosis is based on the medical history and physical examination. As the course of the disease is usually mild, diagnostic tests are not necessary.

Differential Diagnosis

1. Acute pharyngitis of other etiology, predominantly streptococcal (see Pharyngitis (Tonsillitis)).

2. Bacterial sinusitis; distinguishing between viral and bacterial etiologies on the basis of the clinical presentation and even some investigations may be difficult (imaging studies reveal sinus abnormalities in almost 90% of patients).

3. Influenza, laryngitis, bronchitis, and pneumonia.

4. The prodromal phase of various systemic infectious diseases (eg, measles, varicella, mumps, pertussis).

5. Allergic rhinitis: Persistent signs and symptoms of rhinitis.

Treatment Top

Antiviral Treatment

No specific antiviral treatment is available.

Symptomatic Treatment

In symptomatic patients:

1) Echinacea preparations may be consideredEvidence 1Weak recommendation (benefits likely outweigh downsides, but the balance is close or uncertain; an alternative course of action may be better for some patients). Moderate Quality of Evidence (moderate confidence that we know true effects of the intervention). Quality of evidence lowered due to heterogeneity of findings and imprecision. Karsch-Völk M, Barrett B, Kiefer D, Bauer R, Ardjomand-Woelkart K, Linde K. Echinacea for preventing and treating the common cold. Cochrane Database Syst Rev. 2014 Feb 20;2:CD000530. doi: 10.1002/14651858.CD000530.pub3. Review. PubMed PMID: 24554461; PubMed Central PMCID: PMC4068831.; they may reduce the duration of symptoms. The wide variation in available echinacea preparations makes it difficult to recommend a particular form or dose. Vitamin C after the onset of symptoms is not effective in treatment.Evidence 2Weak recommendation (downsides likely outweigh benefits, but the balance is close or uncertain; an alternative course of action may be better for some patients). Moderate Quality of Evidence (moderate confidence that we know true effects of the intervention). Quality of Evidence lowered due to imprecision. Hemilä H, Chalker E. Vitamin C for preventing and treating the common cold. Cochrane Database Syst Rev. 2013 Jan 31;1:CD000980. doi: 10.1002/14651858.CD000980.pub4. Review. PubMed PMID: 23440782. The use of zinc lozenges may be considered within 24 hours of symptom onset, as these have been shown to reduce the duration of the coldEvidence 3Weak recommendation (benefits likely outweigh downsides, but the balance is close or uncertain; an alternative course of action may be better for some patients). Moderate Quality of Evidence (moderate confidence that we know true effects of the intervention). Quality of Evidence lowered due to heterogeneity.Singh M, Das RR. Zinc for the common cold. Cochrane Database Syst Rev. 2011 Feb 16;(2):CD001364. doi: 10.1002/14651858.CD001364.pub3. Review. Update in: Cochrane Database Syst Rev. 2013;6:CD001364. PubMed PMID: 21328251. Singh M, Das RR. Zinc for the common cold. Cochrane Database Syst Rev. 2013 Jun 18;6:CD001364. doi: 10.1002/14651858.CD001364.pub4. Review. Update in: Cochrane Database Syst Rev. 2015;4:CD001364. PubMed PMID: 23775705.; their use may be associated with a bad taste or nausea.

2) When necessary, nasal decongestants or saline nasal irrigation (isotonic or hypertonic [2.5%-3% sea salt solutions]) may be used.Evidence 4Weak recommendation (benefits likely outweigh downsides, but the balance is close or uncertain; an alternative course of action may be better for some patients). Low Quality of Evidence. Quality of Evidence for saline irrigation was lowered due to the unclear or high risk of bias, heterogeneity of treatment effect, and small sample sizes. King D, Mitchell B, Williams CP, Spurling GK. Saline nasal irrigation for acute upper respiratory tract infections. Cochrane Database Syst Rev. 2015 Apr 20;4:CD006821. doi: 10.1002/14651858.CD006821.pub3. PubMed PMID: 25892369. Analgesics and antipyretics (acetaminophen [INN paracetamol], nonsteroidal anti-inflammatory drugs) may also be used to relieve discomfort.Evidence 5Weak recommendation (benefits likely outweigh downsides, but the balance is close or uncertain; an alternative course of action may be better for some patients). Low Quality of Evidence. Quality of Evidence for acetaminophen (paracetamol) was lowered due to the risk of bias. Quality of Evidence for NSAIDs was lowered due to the risk of bias and imprecision. Li S, Yue J, Dong BR, Yang M, Lin X, Wu T. Acetaminophen (paracetamol) for the common cold in adults. Cochrane Database Syst Rev. 2013 Jul 1;7:CD008800. doi: 10.1002/14651858.CD008800.pub2. Review. PubMed PMID: 23818046.Kim SY, Chang YJ, Cho HM, Hwang YW, Moon YS. Non-steroidal anti-inflammatory drugs for the common cold. Cochrane Database Syst Rev. 2015 Sep 21;9:CD006362. doi: 10.1002/14651858.CD006362.pub4. [Epub ahead of print] Review. PubMed PMID: 26387658. Cough suppressants: see Cough.

3) Increased fluid intake in febrile patients and limitation of physical activity to a tolerated level.Evidence 6Weak recommendation (benefits likely outweigh downsides, but the balance is close or uncertain; an alternative course of action may be better for some patients). Low Quality of Evidence (low confidence that we know true effects of the intervention). Quality of Evidence lowered due to the lack of experimental or observational evidence to support this common practice based on widespread clinical experience.

Complications Top

Complications of the common cold include bacterial sinusitis and bacterial otitis media (particularly in children). Prophylactic antimicrobial treatment in patients with the common cold does not reduce the risk of these complications.

Prevention Top

Maintaining good hand hygiene after contact with a sick individual as well as patient isolation are the essential prevention methods.Evidence 7Strong recommendation (benefits clearly outweigh downsides; right action for all or almost all patients). Moderate Quality of Evidence. Quality of Evidence lowered due to heterogeneity present in a meta-analysis and a separate systematic review. Jefferson T, Del Mar CB, Dooley L, et al. Physical interventions to interrupt or reduce the spread of respiratory viruses. Cochrane Database Syst Rev. 2011 Jul 6;(7):CD006207. doi: 10.1002/14651858.CD006207.pub4. Review. PubMed PMID: 21735402. Aiello AE, Coulborn RM, Perez V, Larson EL. Effect of hand hygiene on infectious disease risk in the community setting: a meta-analysis. Am J Public Health. 2008 Aug;98(8):1372-81. doi: 10.2105/AJPH.2007.124610. Epub 2008 Jun 12. PubMed PMID: 18556606; PubMed Central PMCID: PMC2446461. Other nonspecific measures reducing the risk of infection may include echinacea preparationsEvidence 8Weak recommendation (benefits likely outweigh downsides, but the balance is close or uncertain; an alternative course of action may be better for some patients). Low Quality of Evidence (low confidence that we know true effects of the intervention). Quality of Evidence lowered due to imprecision and indirectness. Karsch-Völk M, Barrett B, Kiefer D, Bauer R, Ardjomand-Woelkart K, Linde K. Echinacea for preventing and treating the common cold. Cochrane Database Syst Rev. 2014 Feb 20;2:CD000530. doi: 10.1002/14651858.CD000530.pub3. Review. PubMed PMID: 24554461; PubMed Central PMCID: PMC4068831 and moderate but regular exercise.