Approach
The approach to the diagnosis of the common cold should include:
A history eliciting a constellation of symptoms compatible with the diagnosis
Identification of risk factors suggestive of the condition (for example, seasonal occurrence, smoking, exposure to affected individuals)
A brief physical examination, including temperature, pulse and blood pressure, and examination of oropharynx, nares, neck, and chest. If the patient is unwell or observations are outside of normal limits, consider other causes or complications such as influenza serious bacterial infections such as pneumonia or meningitis, or sepsis, and tailor physical examination accordingly
Excluding alternative diagnoses by screening for distinguishing features of conditions with overlapping symptoms, such as allergic rhinitis.
Children with fever should be comprehensively assessed, see Assessment of fever in children.
No laboratory tests are required in the initial stages.
History
Common symptoms include any or all of the following:
Runny/blocked nose
Sneezing
Sore throat
Cough
Headache
Malaise
Fever.
An alternative or underlying diagnoses should be considered if:
A sore throat is the main symptom (streptococcal pharyngitis or tonsillitis should be considered, especially if the patient is younger than 15 years of age). Use of the McIsaac scorecan be useful to differentiate from streptococcal infection [ Sore Throat (Pharyngitis) Evaluation and Treatment Criteria (McIsaac) Opens in new window ] [27]
Rhinitis has been present for more than 14 days (e.g., allergic rhinitis)
The illness started suddenly with fever, chills, and severe muscle aches (e.g., influenza or pneumonia)
Symptoms include:
Pleuritic pain, large amounts of sputum, or blood in the sputum (e.g., pleurisy or pneumonia)
Otalgia (e.g., otitis media)
Facial pain (sinusitis)
Features of meningism are present (altered consciousness, photophobia, hypotonia, neck stiffness, seizures, and tachycardia).
Consider diagnostic testing for COVID-19 if suspected as it is difficult to differentiate between the two conditions based on symptoms alone. See Differentials.
Physical examination
Temperature:
In adults, an elevated temperature is unusual, but this is common in children. A temperature greater than 38°C (100.4°F) increases the likelihood of the diagnosis being influenza.[28] Pulse and blood pressure should be measured and documented. If the patient is unwell or observations are outside normal limits, consider other causes or complications such as influenza, serious bacterial infections such as pneumonia or meningitis, or sepsis, and tailor the physical examination accordingly.
Children with fever should be comprehensively assessed, see Assessment of fever in children.
Examination of the oropharynx:
A typical viral infection will have non-specific erythematous inflammation of the pharynx. Purulent drainage in the posterior pharynx may be present. The presence of pus on the tonsils is suggestive of streptococcal infection and should be followed by an examination of the anterior cervical glands of the neck.
Nares:
Erythema and oedema may be present. Purulent drainage in both nares is common.
Neck stiffness:
Should be assessed as may indicate meningism. In infants, a bulging fontanelle and a characteristic high-pitched cry may occur. A positive Kernig's or Brudzinski's sign indicates meningeal inflammation and is suggestive of meningitis. This is present in a minority of patients.
For a diagnosis of the common cold, a clear chest is essential. If the patient has lower respiratory signs, other diagnoses should be considered, such as an acute exacerbation of asthma or COPD or pneumonia. In children, bronchiolitis and croup should be considered.
Consider diagnostic testing for COVID-19 if suspected as it is difficult to differentiate between the two conditions based on symptoms alone. See Differentials.
Laboratory tests
No laboratory tests are needed to confirm the diagnosis. However, consider diagnostic testing for COVID-19 if suspected. See Differentials.
Using a point-of-care test for C-reactive protein in primary care settings for patients who present with acute respiratory symptoms can reduce antibiotic use, but with no effect on patient-reported outcomes.[29] There is no consensus on the place of point-of-care testing for the common cold.
At follow-up, where symptoms have persisted beyond normal disease duration or atypical features are present, laboratory investigations may be justified. Specific tests can confirm or exclude alternative diagnoses, such as a throat swab to exclude streptococcal pharyngitis or a chest x-ray to confirm pneumonia. The Monospot test should be ordered when there is clinical suspicion of infectious mononucleosis.
Rapid viral testing has not been shown to reduce antibiotic use; it has been shown to reduce the need for chest x-rays in the accident and emergency department but has not been demonstrated to have any other effects on other tests or waiting times.[30] Viral testing has a place only as part of research or as a tool for the early diagnosis of influenza during a pandemic.
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