What Is the Difference Between a Cold and the Flu?
The flu and the common cold are contagious respiratory diseases with shared symptoms, but both diseases are actually caused by different viruses.1 The flu is caused by influenza viruses, while the common cold can be caused by multiple different viruses, such as rhinoviruses, parainfluenza, and seasonal coronaviruses. Seasonal coronaviruses are different from the virus that causes COVID-19.1
Flu symptoms are typically more intense than cold symptoms, and the flu comes on more abruptly than a cold.1 Colds are usually milder than the flu and generally don’t cause complications, while the flu can lead to more serious health complications.1
Shared Symptoms Between the Cold and the Flu
It can be hard to distinguish between the cold and the flu because they both have multiple symptoms in common. The following symptoms overlap between the cold and the flu, but the severity of the symptoms will vary.2
- Cold: muscle aches can appear when you have a cold, but they are typically mild.
- Flu: muscle aches are a common symptom of the flu and can be severe.
- Cold: feeling fatigued can be a symptom of a cold, but it’s usually mild and doesn’t turn into extreme exhaustion.
- Flu: It’s common to feel like you have no energy when you’re sick with the flu. You might feel extreme exhaustion that comes on suddenly and continues even after you’ve started to recover from the flu.
Runny Nose, Sore Throat, Sneezing
- Cold: it’s common to have a runny nose, sore throat, and sneezing when you have a cold.
- Flu: you might have a runny nose, sore throat, and sneezing with a flu, but these symptoms are more commonly seen in colds.
- Cold: a mild cough typically accompanies a cold.
- Flu: coughing is common with the flu, and it can become quite severe.
- Cold: a mild headache can be a symptom of a cold.
- Flu: Headaches are common when you have the flu. They can come on suddenly and feel severe.
- Cold: It’s rare for adults and older children to develop a fever when they have a cold. However, infants and small children can develop a fever as high as 102oF with their cold.
- Flu: A fever is a common symptom of the flu. It can last for three to four days and reach temperatures between 102oF and 104oF.2
How Does the Cold and the Flu Spread?
Cold and flu viruses are spread via tiny droplets in the air that get released when someone with a cold or flu coughs or sneezes.3 If the infected person is nearby, you can catch the disease by inhaling the droplets directly or by touching droplets on a surface and transferring them to your face. If you’re sick with the flu, you can infect others one day before your symptoms appear and up to five to ten days after getting sick. Colds are the most contagious during the first two to three days and stop being contagious around day seven to ten.3
How Long Do Cold and Flu Droplets Live?
Depending on where they fall outside of your body, cold and flu droplets can remain infectious for several hours.4 Viruses live longer on hard surfaces, such as stainless steel and plastic, than they do on soft surfaces, such as fabric and carpet.Other factors help determine how long a virus can live outside your body, such as the temperature and humidity of the environment, and the number of droplets deposited on the surface.4
When to See a Doctor for a Cold
Most adults don’t need to seek medical attention for a common cold. However, contact your doctor if you are experiencing any of the following symptoms:5
- Symptoms that get worse or never improve
- A fever over 101.3oF that lasts over three days
- A fever that returns after a fever-free period
- Shortness of breath
- Severe pain, sinus pain or throat pain
- Severe headaches that don’t go away
When to See a Doctor for a Flu
Adults who get the flu usually treat their symptoms at home and don’t need to see a medical professional. However, if you know you’re at risk of experiencing complications from the flu, contact your doctor at the onset of your symptoms. If you’re experiencing any of the following emergency signs of the flu, seek medical attention right away. Emergency symptoms of the flu include:6
- Chest pain
- Severe weakness or muscle pain
- Existing medical conditions that get worse
- Ongoing dizziness
- Shortness of breath and difficulty breathing
Lifestyle and Home Remedies
Adults who aren’t experiencing emergency symptoms can usually treat their cold and flu symptoms at home. Try one or more of these solutions to ease your symptoms:7
- Stay hydrated. Drink plenty of fluids, such as water, juice, and soup/broth to prevent dehydration.
- Rest. Getting enough sleep helps your immune system fight off infections. If you’re having severe symptoms, you might have to scale back your overall activity level. If you have a fever, try to take the day off work.
- Take an over-the-counter pain reliever. OTC pain relievers can help combat the aches and pains associated with the flu or a cold.
- Adjust your room’s temperature and humidity. Keeping your room warm, not hot, and adding a cool-mist humidifier or vaporizer can help ease your congestion and coughing
- Soothe your sore throat. Gargle with a saltwater solution, or try ice chips, lozenges, or hard candy to soothe your throat. To make a saltwater gargle, just add 1/4 to 1/2 teaspoon of table salt to 4 to 8 ounces of warm water. Gargle the solution and then spit it out.
- Try a saline nasal spray. Nasal sprays are designed to keep your nasal passages moist and loosen the mucus in your nose.
- Sip on a soothing cup of Theraflu. Soothe your cold or flu symptoms and get back on your feet with one of Theraflu’s great-tasting hot liquid powders. The warm liquid provides soothing comfort while the powerful ingredients provide quick relief from your cold and flu symptoms.
1. Cold Versus Flu. CDC. https://www.cdc.gov/flu/symptoms/coldflu.htm. Accessed 10/25/21.
2. Cold or Flu? | Patient Education. UCSF Health. https://www.ucsfhealth.org/education/cold-or-flu. Accessed 10/25/21.
3. Cold and Influenza. APIC. https://apic.org/monthly_alerts/cold-and-influenza/. Accessed 10/25/21.
4. Cold and flu viruses: How long can they live outside the body? Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/flu/expert-answers/infectious-disease/faq-20057907. Accessed 10/28/21.
5. Common cold - Symptoms and causes. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/common-cold/symptoms-causes/syc-20351605. Accessed 10/25/21.
6. Influenza (flu) - Symptoms and causes. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/flu/symptoms-causes/syc-20351719. Accessed 10/25/21.
7. Cold remedies: What works, what doesn't, what can't hurt. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/common-cold/in-depth/cold-remedies/art-20046403. Accessed 10/25/21.