Diagnosis

Your doctor will evaluate your symptoms to determine whether you have influenza or a cold. If you are sneezing and have a stuffy nose, you may have a cold. Influenza is more likely to cause fever, coughing, chills and muscle aches. It also is more seasonal than colds. Flu tends to occur during winter months, whereas colds occur all year long.

Most of the time, doctors assume the diagnosis is influenza when you have an illness in the winter with the symptoms of influenza. If your symptoms or findings on physical examination suggest something other then the flu, your doctor may order blood tests and swab your nose and throat to send secretions to the laboratory for specific influenza testing. Your doctor may order a chest X-ray if he or she suspects that the influenza virus has caused a lung infection (pneumonia) or may lead to a bacterial superinfection and pneumonia.

Expected Duration

Influenza symptoms can last for as few as 24 hours, or for a week or more. A typical case lasts four or five days. As long as you have symptoms, you are contagious and can spread the infection to others.