Cold or Flu? How to Tell the Difference

Influenza, or the flu, can be tricky to tell apart from the common cold. Both are respiratory illnesses caused by viruses, and they share many symptoms.

Because colds and the flu are caused by viruses rather than bacteria, antibiotics aren’t an effective treatment option for either infection.

Both the flu and colds affect the respiratory system, though flu symptoms are typically more severe.

“There are many different viruses that can cause a cold, but most of these viruses cause very similar cold symptoms,” says Aaron E. Glatt, MD, chief of infectious diseases at Mount Sinai South Nassau in Oceanside, New York.

• Headache
• Sore throat
• Cough
• Runny nose and nasal congestion
• Sneezing

Flu and cold viruses are respiratory viruses which can be spread through the air, personal contact, and respiratory secretions. Encounters like handshakes, touching contaminated objects, and exposure to sneezes or coughs can lead to infection.

• Children younger than 5
• People with weakened immune systems
• People with underlying medical conditions, such as asthma

Colds are typically diagnosed by evaluating symptoms and ruling out other conditions rather than through testing. Your doctor may also perform a physical exam.

Test results are usually ready in less than 15 minutes but are not always accurate. Other more reliable flu tests can be performed only in hospitals or specialized laboratories.

The duration of a cold or the flu varies depending on the virus involved and your immune system’s ability to fight off infection. That’s why the very young, older adults, and people with chronic illnesses are most susceptible to viral infections and possible complications.

“The best weapon we have is our own immune system,” says Donald W. Novey, MD, a family medicine physician at MultiCare Family Medicine in Poulsbo, Washington.

Good nutrition, adequate sleep and exercise, and low levels of stress can bolster the immune system. “A failure on any one of these four points can weaken the immune system and either prolong an existing cold or lead to more frequent ones,” Dr. Novey says.

There’s no cure for either the flu or the common cold, but many medications can help treat symptoms while your body fights the infection.

• Throat lozenges or sprays
• Cough suppressants
• Saline drops or sprays
• Decongestants
• Pain relievers or fever reducers

• Washing your hands regularly
• Avoid touching your eyes, face, or mouth
• Strengthening your immune system
• Staying home if you’re sick
• Wearing a mask in public places

The flu is more likely to cause severe symptoms, but both can lead to health complications. People with existing health conditions like asthma or those with compromised immune systems are at higher risk of developing complications.

• Difficulty breathing
• Chest pain or pressure
• Dizziness or confusion
• Severe muscle pain
• Seizures
• Severe weakness

• Flu symptoms are typically more severe and can develop more quickly than cold symptoms.
• Prescription antiviral drugs are available to treat the flu, particularly for those at higher risk for complications.
• Practicing good hygiene and supporting your immune system can reduce your risk of catching or spreading a cold or the flu.
• If you’re experiencing severe symptoms, such as difficulty breathing, chest pain, dizziness, or weakness, seek medical attention right away.