Most people who have the flu (influenza) have a mild illness and don't need to see a doctor. Common flu signs and symptoms include:

• Fever above 100 F (38 C), though not everyone with the flu has a fever
• A cough or sore throat
• A runny or stuffy nose
• Headache
• Muscle aches
• Chills
• Fatigue
• Nausea, vomiting or diarrhea (most common in children)

With some rest and self-care measures at home, the average healthy person can expect to get better within a week, although a dry cough may last for several weeks.

However, some people are at greater risk of serious flu-related complications and should see a doctor.

Who needs to see a doctor?

If you or someone you're caring for is at high risk of flu-related complications and you suspect the flu, call the doctor. For those at high risk of flu-related complications or who have severe flu, there's a greater chance that the flu might lead to pneumonia, bronchitis, sinus infections, and, rarely, hospitalization or death. The flu can also worsen chronic health problems such as asthma and congestive heart failure.

You have an increased risk of flu-related complications if you:

• Are younger than 12 months old
• Are 65 years old or older
• Are pregnant or have given birth in the past two weeks
• Are younger than 19 years of age and are receiving long-term aspirin therapy
• Have certain chronic medical conditions, including lung diseases such as asthma, an airway abnormality, heart disease, diabetes, neurological or neurodevelopmental disease, metabolic disorders, and kidney, liver or blood disease
• Have a weakened immune system due to factors such as long-term use of steroids or other immunosuppressants, HIV, organ transplant, blood cancer, or cancer being treated with chemotherapy
• Have a body mass index (BMI) of 40 or greater
• Live in a long-term care facility such as a nursing home
• Are in the hospital

If you're in one of these groups or you have evidence of severe influenza infection, your doctor may prescribe an antiviral medication — such as oseltamivir (Tamiflu), zanamivir (Relenza), peramivir (Rapivab) or baloxavir (Xofluza) — to reduce the severity and length of your symptoms.