Diagnosis

To diagnose flu, including swine flu, your doctor will likely conduct a physical exam, look for signs and symptoms of influenza, and possibly order a test that detects influenza viruses.

There are several tests used to diagnose flu, but not everyone who has the flu needs to be tested. In most cases, knowing that someone has the flu doesn't change the treatment plan. Doctors are more likely to use a test to diagnose flu if:

  • You're already in the hospital
  • You're at high risk of complications from the flu
  • You live with someone who is at greater risk of flu complications

Your doctor may also use a test to determine whether a flu virus is the cause of your symptoms, or if you have or are showing signs of another problem besides the flu, such as:

  • Heart problems, such as heart failure or an infection of the heart muscle
  • Lung and breathing problems, such as asthma or pneumonia
  • Brain and nervous system problems, such as encephalopathy or encephalitis
  • Septic shock or organ failure

The most commonly used test is called a rapid influenza diagnostic test, which looks for substances (antigens) on a swab sample from the nose or back of the throat. These tests can provide results in about 15 minutes. However, results vary greatly and are not always accurate. Your doctor may diagnose you with influenza based on symptoms, despite a negative test result.

More-sensitive flu tests are available in some specialized hospitals and labs.

Treatment

Most people with flu, including swine flu, require only symptom relief. If you have a chronic respiratory disease, your doctor may prescribe additional medications to help relieve your symptoms.

There are four FDA-approved antiviral drugs that are sometimes prescribed within the first day or two of symptoms to reduce the severity of symptoms and possibly the risk of complications. These include:

  • Oseltamivir (Tamiflu)
  • Zanamivir (Relenza)
  • Peramivir (Rapivab)
  • Baloxavir (Xofluza)

But flu viruses can develop resistance to these drugs.

To make development of resistance less likely and maintain supplies of these drugs for those who need them most, doctors reserve antivirals for people at high risk of complications and those who are in close contact with people who have high risk of complications.

High-risk groups include people who:

  • Are in a hospital, nursing home or other long-term care facility.
  • Are younger than 5 years of age, particularly children younger than 2 years.
  • Are 65 years old or older.
  • Are pregnant or within two weeks of delivery, including women who have had pregnancy loss.
  • Are younger than 19 years of age and are receiving long-term aspirin therapy. Using aspirin during a viral illness increases the risk of developing Reye's syndrome, a rare but potentially fatal disease, in these individuals.
  • Are morbidly obese, defined as having a body mass index above 40.
  • Have certain chronic medical conditions, including asthma, emphysema, heart disease, diabetes, neuromuscular disease, or kidney, liver or blood disease.
  • Are immunosuppressed due to certain medications or HIV.
  • Are American Indians or Alaska Natives Alaskans.

Lifestyle and home remedies

If you develop any type of flu, these measures may help ease your symptoms:

  • Drink plenty of liquids. Choose water, juice and warm soups to prevent dehydration.
  • Rest. Get more sleep to help your immune system fight infection.
  • Consider pain relievers. Use an over-the-counter pain reliever, such as acetaminophen (Tylenol, others) or ibuprofen (Advil, Motrin IB, others), cautiously. Also, use caution when giving aspirin to children or teenagers.

Though aspirin is approved for use in children older than age 3, children and teenagers recovering from chickenpox or flu-like symptoms should never take aspirin. This is because aspirin has been linked to Reye's syndrome.

Remember, pain relievers may make you more comfortable, but they won't make your symptoms go away faster and they have side effects. Ibuprofen may cause stomach pain, bleeding and ulcers. If taken for a long period or in higher than recommended doses, acetaminophen can be toxic to your liver.

Swine flu (H1N1 flu) care at Mayo Clinic

Jan. 10, 2019
  1. Key facts about human infections with variant viruses (swine origin influenza viruses in humans). Centers for Disease Control and Prevention. https://www.cdc.gov/flu/swineflu/keyfacts-variant.htm. Accessed Nov. 26, 2018.
  2. Thorner AR. Epidemiology of pandemic H1N1 influenza ('swine influenza'). https://www.uptodate.com/contents/search. Accessed Nov. 26, 2018.
  3. Grohskopf LA, et al. Prevention and control of seasonal influenza with vaccines: Recommendations of the Advisory Committee on Immunization Practices — United States, 2018-2019 influenza season. MMWR Recommendations and Reports. 2018;67:3.
  4. Cohen J, et al. Influenza viruses. In: Infectious Diseases. 4th ed. Philadelphia, Pa.: Elsevier Limited; 2017. https://www.clinicalkey.com. Accessed Nov. 26, 2018.
  5. The flu: What to do if you get sick. Centers for Disease Control and Prevention. https://www.cdc.gov/flu/takingcare.htm. Accessed Nov. 26, 2018.
  6. Lantos PM, et al. Are people living near modern swine production facilities at increased risk of influenza virus infection? Clinical Infectious Diseases. 2016;63:1558.
  7. Bailey ES, et al. A mini review of the zoonotic threat potential of influenza viruses, coronaviruses, adenoviruses, and enteroviruses. Frontiers in Public Health. 2018;6:104.
  8. AskMayoExpert. Influenza vaccination. Rochester, Minn.: Mayo Foundation for Medical Education and Research; 2018.
  9. Show me the science – situations where hand sanitizer can be effective & how to use it in community settings. Centers for Disease Control and Prevention. https://www.cdc.gov/handwashing/show-me-the-science-hand-sanitizer.html. Accessed Nov. 26, 2018.
  10. Guide for considering influenza testing when influenza viruses are circulating in the community. Centers for Disease Control and Prevention. https://www.cdc.gov/flu/professionals/diagnosis/consider-influenza-testing.htm. Accessed Nov. 27, 2018.
  11. Steckelberg J (expert opinion). Mayo Clinic, Rochester, Minn. Nov. 30, 2018.
  12. Reye syndrome. Merck Manual Professional Version. https://www.merckmanuals.com/professional/pediatrics/miscellaneous-disorders-in-infants-and-children/reye-syndrome. Accessed Nov. 27, 2018.
  13. Ibuprofen drug facts label. U.S. Food and Drug Administration. https://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/ucm125225.htm. Accessed Nov. 27, 2018.
  14. Acetaminophen oral. Facts & Comparisons eAnswers. https://www.wolterskluwercdi.com/facts-comparisons-online/. Accessed Nov. 29, 2018.
  15. Variant influenza viruses: Background and CDC risk assessment and reporting. Centers for Disease Control and Prevention. https://www.cdc.gov/flu/swineflu/variant.htm. Accessed Jan. 7, 2019.