How to tell the difference between cold, flu and RSV symptoms

Cold & Flu

by Mark Hinds, MD

Nov 13, 2024

We’ve all been there—sniffling, sneezing and trying to figure out whether it’s just a cold, the flu or RSV. With so many overlapping symptoms, it can be tricky to determine which virus is behind your or your family’s symptoms.

But knowing the difference is important because it can help you manage your symptoms more effectively and avoid spreading the illness to others.

Let’s break down the key differences between the common cold, flu and RSV symptoms, including the main distinguishing features and when you or your child might want to see a doctor.

What causes cold, flu and RSV symptoms?

Before we get into the symptoms, let’s take a quick look at what causes each of these illnesses.

The common cold is typically caused by rhinoviruses, but other viruses can cause it too. Colds are very common, and most adults catch two to three colds each year.

The flu is caused by the influenza virus, which comes in several strains. Flu season tends to peak in the colder months, though it’s possible to catch the flu at other times of year. It’s important to get a flu shot every year to help protect yourself against the virus.

Respiratory Syncytial Virus (RSV) is a virus that primarily affects the respiratory system. While RSV is most commonly associated with infants and young children, it can also affect adults, especially older adults and those with weakened immune systems. There is an RSV vaccine available, and your doctor may recommend it if you fall into one of those high-risk groups.

Cold, flu or RSV symptoms?

While the symptoms of these three illnesses can be similar, there are a few key differences to know.

Cold symptoms

We all know what it’s like to have a cold—those annoying sniffles, a scratchy throat and generally feeling a bit off. Colds typically come on slowly, and the symptoms are relatively mild.

Colds almost always involve nasal congestion or a runny nose. Common cold symptoms include:

  • Runny or stuffy nose
  • Sore throat
  • Sneezing
  • Cough
  • Mild fatigue
  • Low-grade fever (rare in adults but more common in kids)

A cold is typically more of a nuisance than a serious health issue. You might feel under the weather for a few days to a week, but you should be able to go about your day normally, albeit with tissues in hand.

Flu symptoms

Now, if you wake up one morning feeling like you’ve been hit by a truck, chances are you’re dealing with the flu. Unlike a cold, the flu tends to hit suddenly and strongly.

Common flu symptoms include:

  • Sudden high fever (usually over 100.4°F or 38°C)
  • Chills and body aches
  • Headache
  • Sore throat
  • Dry, persistent cough
  • Fatigue (often severe)
  • Occasional runny or stuffy nose

The biggest difference between the flu and a cold is the intensity. With the flu, you’re likely to feel much worse and experience more significant fatigue. Fever is also a common flu symptom, whereas it’s rare in adults with a cold.

Flu symptoms tend to last about a week, but it can take longer to fully recover and get over the lingering fatigue.

RSV symptoms

For most healthy adults, RSV causes mild, cold-like symptoms. However, in certain cases—especially in infants and young children, as well as older adults—RSV can lead to more serious respiratory problems, such as bronchiolitis or pneumonia.

Common RSV symptoms include:

  • Runny nose (often with copious nasal secretions)
  • Decreased appetite
  • Cough (which may progress to wheezing)
  • Sneezing
  • Fever
  • Trouble breathing (especially in infants or older adults)
  • Bluish color around lips (in severe cases)

For most healthy adults, RSV might just feel like a bad cold, but it’s important to watch out for signs of breathing difficulty. RSV usually peaks around day 3-5 of the illness. In infants, RSV can lead to severe respiratory distress, so if you notice your child having difficulty breathing, breathing very rapidly or wheezing, it’s important to seek medical attention right away.

Tips for managing cold, flu and RSV symptoms at home

Whether you’re dealing with a cold, the flu or RSV, there are several things you can do to manage your symptoms at home while you recover.

  • Rest: No matter which virus you have, your body needs rest to recover. Take it easy, and don’t try to push through.
  • Stay hydrated: Drink plenty of fluids, especially water, tea and broth. Staying hydrated helps thin mucus and prevents dehydration, especially if you have a fever.
  • Use over-the-counter medications: Medications like ibuprofen or acetaminophen can help with fever and aches, while decongestants and saline sprays can ease nasal congestion.
  • Use a humidifier: Using a humidifier can add moisture to the air, which helps relieve congestion and soothe a dry throat or cough.

When to see a doctor for cold, flu or RSV symptoms

While most people recover from a cold, the flu or RSV on their own with rest, fluids and over-the-counter medications, there are times when you should seek medical attention.

  • Cold: If your cold symptoms last longer than 10 days, or if you develop a high fever, ear pain or sinus pain, it could indicate a secondary infection like sinusitis or an ear infection. See your doctor if you’re concerned.
  • Flu: Seek medical help if you experience shortness of breath, chest pain, persistent high fever or confusion. The flu can also lead to complications like pneumonia, so don’t hesitate to call your doctor if your symptoms worsen.
  • RSV: Watch for any signs of difficulty breathing, wheezing or dehydration (especially in infants and elderly adults). If you or your child are having trouble breathing, seek medical attention immediately.

Get well soon! If you’re ever unsure about your symptoms, or if you’re concerned about breathing difficulties or worsening conditions, it’s always best to check with your healthcare provider. Find a doctor near you or explore our virtual care options.

About the Author

Mark Hinds, MD, is a family medicine physician on the medical staff at Baylor Scott & White Medical Center – Hillcrest. He has practiced outpatient and hospital medicine in Waco since 1995. He attended medical school at UT Health Science Center San Antonio and completed his residency in Waco. He currently lives in Crawford, Texas, with his wife Michelle.

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