Symptoms

Sudden and severe onset: Muscle aches and extreme fatigue Dry cough Sore throat Headache Chills and fever to 104 degrees

The more common "head cold" is typified by a gradual onset of symptoms including nasal congestion, sneezing, sore throat, dry cough, and low-grade fever rarely over 100 degrees.

Your physician may order a lab test utilizing a nasopharyngeal swab to confirm the diagnosis of influenza but most often the diagnosis is made on the basis of patient symptoms in the presence of a flu epidemic.