What Are the Early Signs of the Flu?

Wondering if you have the flu? Early flu symptoms can vary. Some people may have a cough as their first symptom, while other people will first notice fatigue, a headache, or a fever.

One telltale sign of the flu is how quickly symptoms develop. With colds, symptoms come on gradually. The first day of a cold might be only slight, with more intense symptoms hitting the next day or two.

Early flu symptoms, on the other hand, tend to hit quickly. People often feel quite well one day to quite sick the next.

It is important to recognize the flu symptoms early. That way, if you’re sick, you can avoid elderly people and others who may be risk of getting very sick from the flu.

If you’re at a high risk from the flu, recognizing symptoms early allows you to see your doctor for anti-flu medication ASAP. This will reduce your risk of complications and help you recover faster.

Never Miss a Beat!

Get Healthy Tips Sent to Your Phone!

Message and data rates may apply. Text the word STOP to opt out and HELP for help. Click here to view the privacy and terms.

What Are Common Early Flu Symptoms?

During the early stages of the flu, people often experience:

  • A fever (a temperature of 100.4°F or higher).
  • Body aches.
  • A headache.
  • Coughing.
  • A sore throat.
  • A runny or stuffed up nose.
  • Chills.
  • Fatigue.

It’s important to note that some people don’t experience a fever with a flu. People, age 65 and older, are less likely to experience a fever than younger people. The fevers they do experience are often lower, right around the 100°F mark.

Getting Tested for the Flu

To receive treatment for the flu, you need to confirm that you actually have the flu and not something else. COVID-19 symptoms can be very similar to the flu — and may come on gradually or suddenly. The only way to know if you have COVID-19 or the flu is to take a COVID-19 test.

Contact your doctor’s office and ask if they can do a rapid test to see if you have the flu or COVID-19. Results are typically available within 20 minutes.

If a rapid test for COVID-19 or the flu is negative, you could still have either virus. That’s because these tests do not always pick up the virus, especially in the first day or two of symptoms.

You can try the test again after a couple of days. Or, your doctor may recommend a more accurate PCR test, for which results take several hours to days.

Even if the results of a rapid test are negative, your doctor may still treat you with an antiviral drug. This is because rapid tests are prone to false negatives, especially in the first day or two of symptoms.

Treatment in the Early Stages of a Flu

There are antiviral medications you can take to treat the flu. But the medication works best when it’s taken within 48 hours of the start of symptoms.

That’s why it’s so important that to contact your doctor promptly if you have early flu symptoms and are at higher risk of developing flu complications. Those at a higher risk of getting very sick from the flu include:

  • People aged 65 and older.
  • People with certain underlying health conditions, including asthma, diabetes and heart disease.
  • Pregnant people.

Doctors will recommend an antiviral drug approved for the flu for high-risk individuals. This medication can lower the length of a flu and reduce the chances of getting very sick or dying from the flu.

There are four different antiviral drugs approved for high-risk patients in the early stages of a flu:

  • Oseltamivir phosphate (Tamiflu).
  • Zanamivir (Relenza).
  • Peramivir (Rapivab).
  • Baloxavir marboxil (Xofluza).

The drug that the doctor chooses depends on a person’s age, whether they are pregnant or breastfeeding, and other drugs they’re taking.

What to Expect With the Flu

The early stages of the flu are usually the worst. If you aren’t in a high-risk group, you may notice that you have more energy and your fever is gone after a few days. Most people with a typical flu recover within a week.

But in rare cases, even healthy people can develop serious health problems from the flu. These complications can develop in as little as two days. Or they may not show up for a week or two after the first day of the flu.

Serious complications of the flu include pneumonia, inflammation of the heart or brain, respiratory distress, and organ failure.

The following are signs of serious flu complications in adults:

  • Difficulty breathing.
  • Dehydration (not urinating).
  • Signs of worsening chronic conditions, like asthma or a heart condition.
  • Fever or cough that improves but then comes back
  • Fever or cough that gets worse after a week, rather than better.
  • Confusion.
  • Pressure or pain in the chest.
  • Any symptom you’re worried could be the sign of a flu complication.

If you develop any of the above symptoms, see your doctor right away.

Sources

American Lung Association. Flu symptoms, causes, and risk factors. Link

Drs. Sameh Boktor and John Hafner. Influenza. StatPearls. Link

Centers for Disease Control and Prevention. Diagnosing flu. Link

Centers for Disease Control and Prevention. Flu symptoms and complications. Link

Centers for Disease Control and Prevention. Key facts about influenza. Link

Centers for Disease Control and Prevention. Study shows hospitalization rates and risk of death from seasonal flu increase with age among people 65 years and older. Link

Centers for Disease Control and Prevention. Influenza Antiviral Medications: Summary for Clinicians. Link

About UPMC

Headquartered in Pittsburgh, UPMC is a world-renowned health care provider and insurer. We operate 40 hospitals and 800 doctors’ offices and outpatient centers, with locations throughout Pennsylvania, Maryland, New York, West Virginia, and internationally. We employ 4,900 physicians, and we are leaders in clinical care, groundbreaking research, and treatment breakthroughs. U.S. News & World Report consistently ranks UPMC Presbyterian Shadyside as one of the nation’s best hospitals in many specialties and ranks UPMC Children’s Hospital of Pittsburgh on its Honor Roll of America’s Best Children’s Hospitals. We are dedicated to providing Life Changing Medicine to our communities.