What is flu (influenza)?

Flu (Influenza)

Influenza (flu) in teens: Overview

Influenza (flu) is an infection in the respiratory tract. It is caused by the influenza virus. There are different strains of the flu virus from year to year. Unlike the common cold, the flu comes on suddenly, and the symptoms, such as a cough, congestion, fever, chills, fatigue, aches, and pains, are more severe. These symptoms may last for a few weeks. Although the flu can make you feel very sick, it usually does not cause serious health problems.

Home treatment is usually all you need for flu symptoms. But your doctor may prescribe antiviral medicine to prevent other health problems, such as pneumonia, from developing. Teens who have a long-term health condition, such as asthma, are more at risk for having pneumonia or other health problems.

Influenza (flu)

Influenza (flu) is an infection, caused by a virus, that makes you feel very sick, often with fever, headache, body aches, and coughing.

People often use the term "flu" to describe a cold or a stomach virus. But influenza isn't a stomach problem (although some little children may have vomiting and diarrhea). And it usually feels much worse than a cold.

What are the symptoms of influenza (flu)?

Flu symptoms may include fever, body aches, a headache, a dry cough, and a sore or dry throat. You'll probably feel tired and less hungry than usual. The symptoms are usually worse for the first few days. But it can take up to a few weeks to get completely better.

How is influenza (flu) treated?

Most people can treat flu symptoms at home with rest, medicines, or other treatment. Your doctor may give you medicine that can make the symptoms milder. But some people need treatment in the hospital. They may have severe symptoms or get pneumonia. Or the flu infection may make an existing health problem worse.

How can you prevent influenza (flu)?

You can help prevent the flu by getting the flu vaccine every year. It's best to get the vaccine as soon as it's available. The U.S. Centers for Disease Control and Prevention recommends that everyone 6 months old and older get a flu vaccine.

How is influenza (flu) diagnosed?

Your doctor will ask you about your symptoms and will examine you. This usually gives the doctor enough information to find out if you have the flu. Sometimes the doctor will do a test to check for the flu.

How can you care for yourself when you have influenza (flu)?

Get lots of rest and drink plenty of fluids. Breathe moist air to help a stuffy nose. For coughing, drink fluids to soothe your throat and suck on cough drops or hard candy. Elevate your head at night if coughing wakes you up. Take over-the-counter medicines for pain or cough if needed.

Who is most at risk for influenza (flu)?

Anyone exposed to the flu virus can get the flu. These flu viruses spread easily among people in groups. For example, people in nursing homes, hospitals, shelters, schools, and day care can easily be exposed to the flu virus. Working, visiting, or living in any of these areas puts you at more risk of getting the flu.

The risk of having severe symptoms and complications is higher for:

  • Children younger than 2 years of age.
  • Adults age 65 and older.
  • Pregnant women.
  • People who have chronic obstructive pulmonary disease (COPD), other lung diseases, or heart failure.
  • People who have a medical condition (such as AIDS) or who are using a medicine that impairs the immune system.

What is influenza (flu)?

Influenza (flu) is an infection from a virus. It can cause a fever, body aches, a headache, and a cough. It is contagious and usually lasts about a week or two.

What problems can influenza (flu) cause?

Although most cases of influenza (flu) get better without causing other problems, complications sometimes develop.

Possible problems from the flu include:

  • Pneumonia, which is an infection of the lungs. It rarely causes death in young, healthy people. But it can often be life-threatening in older adults, people who have other diseases, and pregnant women.
  • Bronchiolitis. This is an inflammation of the small air passages. It affects infants and is the leading cause of serious lower respiratory illness.
  • Sinusitis. This means the mucous membranes that line the inside of the nose and facial sinuses become infected and inflamed.
  • Croup. Croup is a swelling or blockage in the windpipe. It causes hoarseness, a barking cough, a high-pitched sound when breathing in, and trouble breathing.
  • Chronic obstructive pulmonary disease (COPD) symptoms may get worse.
  • Inflammation of the heart muscle, the sac around the heart, or other muscles.

What causes influenza (flu)?

The flu is usually caused by the influenza viruses types A and B. There are different subtypes, or strains, of the flu virus every year.

Influenza in teens: When to call

Call 911 anytime you think you may need emergency care. For example, call if:

  • You have severe trouble breathing.
  • You have a seizure.

Call your doctor now or seek immediate medical care if:

  • You have trouble breathing.
  • You have a fever with a stiff neck or a severe headache.
  • You have pain or pressure in your chest or belly.
  • You have a fever or cough that returns after getting better.
  • You feel very sleepy, dizzy, or confused.
  • You are not urinating.
  • You have severe muscle pain.
  • You have severe weakness, or you are unsteady.
  • You have medical conditions that are getting worse.

Watch closely for changes in your health, and be sure to contact your doctor if:

  • You do not get better as expected.
  • You are having a problem with your medicine.

©2011-2024 Healthwise, Incorporated

The content above contains general health information provided by Healthwise, Incorporated, and reviewed by its medical experts. This content should not replace the advice of your healthcare provider. Not all treatments or services described are offered as services by us. For recommended treatments, please consult your healthcare provider.

Specialized emergency services

Find care near you

Comprehensive care

Find an ER near you