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Upper Respiratory Infection: Risk Factors and Diagnosis

Upper respiratory infections (URIs), or colds, can be caused by many families of viruses, such as rhinovirus (which has at least 100 serotypes), coronavirus, and respiratory syncytial virus. URIs are the most common acute illnesses in the industrial world.

Cold symptoms include:

  • Rhinitis (sneezing, nasal congestion, and postnasal drip).
  • Pharyngitis.
  • Cough, usually dry.
  • Fatigue and myalgias.
  • Mild fever.
  • Conjunctivitis.

Risk Factors

Direct contact with individuals who have an upper respiratory infection permits viral transfer. In particular, closed settings such as homes and schools have higher attack rates than work settings. Seasonal variations occur for some viral families. However, cold climates are not necessarily a risk factor for disease occurrence or severity.1

Touching is the most effective mode of transmission. Typically, a person with a cold rubs his or her eyes or nose and then shakes hands or touches objects that others touch later. Saliva is not an effective mode of transmission.


Common cold symptoms are listed above. Colds and influenza typically have few physical findings and often cannot be distinguished reliably in clinical settings. If a definitive diagnosis of influenza is important, certain tests may be useful (see Influenza chapter). Patients with symptoms or signs of lower respiratory infection, such as dyspnea or rales, should be evaluated for pneumonia or exacerbation of chronic lung disease. URIs do not cause signs of systemic inflammatory response; patients who appear seriously ill may require antibiotics or hospital admission.

Upper Respiratory Infection: Prevention and Treatment >>