Diagnosing flu

Diagnosing flu

When to see a doctor

If you are already experiencing flu symptoms it may be necessary to see your doctor if:

  • You experience a persistently high fever lasting more than 3 days. This can be a sign of another bacterial infection, which will require treatment by a medical professional.
  • You experience pain when swallowing. A sore throat can cause mild discomfort when you’re down with the flu, but severe pain can mean that you are suffering from strep throat (a bacterial infection causing pain and inflammation), and this will require treatment recommended by your doctor.
  • You have a persistent cough that doesn’t go away after 2 to 3 weeks. Bronchitis, post nasal drip, sinusitis and even asthma may cause a persistent cough.
  • You are unable to clear nasal congestion and headaches after a week. Allergies or a blockage of sinus passages could be the cause of persistent congestion and headaches and lead to sinusitis (a sinus infection). Pain around the eyes and face with a thick nasal discharge lasting longer than a week could point to a bacterial infection which will require an antibiotic. Most sinus infections, however, won’t likely need an antibiotic to clear at all.

Emergency situations can arise in some cases. Signs of crisis include severe chest pain, severe headache, shortness of breath, dizziness, confusion and persistent vomiting. If any of these symptoms are noted in adults, it is best to get emergency medical attention straight away.

Urgent action will also need to be taken in children experiencing rapid or difficulty breathing, a bluish skin colour, dehydration (not able to take in enough fluids), lethargy and failure to interact normally, extreme distress or irritability, fever with a rash, as well as symptoms that may have shown improvement but suddenly became worse.

How is flu diagnosed?

As most outbreaks of flu tend to occur during the colder months of the year, it is likely that your doctor will diagnose your illness based on your symptoms, the strain of flu already known to be circulating and his / her own clinical judgement.

In some instances, your doctor may request a test in order to make a diagnosis. The most common test which may be requested is the ‘rapid influenza diagnostic test’. Your doctor will swipe the inside of your nose and back of your throat with a swab and send for testing. Results can be received in approximately 30 minutes or less and can help to determine which type of flu virus (A or B) you have been infected with. The test is also useful for ruling out any other potential concerns, such as a bacterial infection, which will require a different course of treatment.

PREVIOUS Risk factors and complications of flu
NEXT Flu treatments