Cold symptoms typically come on gradually, whereas flu symptoms come on quickly and may be severe. OTC medications may help relieve the symptoms of both. The best prevention method for the flu is getting the vaccine.

Symptoms of a seasonal cold or the flu overlap, so unless your doctor runs a rapid flu test — a quick check done with a cotton swab from the back of your nose or throat — it’s hard to know for sure.

Here are some basic guidelines for telling the difference between cold and flu symptoms, and what to do if you have either of these infections.

The simplest way to tell the difference between a cold and the flu is by examining your symptoms.

Cold

Colds come on gradually over a few days and are often milder than the flu. They usually get better in 7 to 10 days, although symptoms can last for up to 2 weeks.

If you have a cold, you’ll likely experience:

Flu

Flu symptoms come on quickly and can be severe. They usually last 1 to 2 weeks.

Flu symptoms may include:

If you think you have the flu, speak with your doctor to get tested within the first 48 hours of showing symptoms.

The common cold is an upper respiratory infection caused by a virus. According to the American Lung Association, more than 200 different viruses can cause it.

The rhinovirus is most often the virus that makes people sneeze and sniffle. It’s highly contagious.

Though you can catch a cold at any time of year, they’re more common during the winter months because most cold-causing viruses thrive in low humidity.

Colds spread when someone who’s sick sneezes or coughs, sending virus-filled droplets flying through the air.

You can get sick if you touch a surface that has recently been handled by a person who’s sick, and then touch your nose, mouth, or eyes.

You’re most contagious in the first two to four days after you’re exposed to the cold virus.

Treatment

A cold is a viral infection, so antibiotics aren’t effective. These only work on bacteria.

Over-the-counter (OTC) medications, such as antihistamines, decongestants, acetaminophen, and NSAIDs, can help relieve congestion, aches, and other symptoms.

Drink plenty of fluids to avoid dehydration.

Colds usually clear up within 7 to 10 days. Speak with a doctor if:

  • your cold hasn’t improved in about a week
  • you start to run a high fever
  • your fever doesn’t go down

Prevention

Doctors haven’t yet developed a cold vaccine, but there are ways to help prevent it:

  • Avoidance: Colds are very contagious. Stay away from anyone who’s sick. Don’t share utensils or any other personal items, such as a toothbrush or towel. Likewise, if you’re sick, stay home.
  • Good hygiene: Wash your hands often with warm water and soap to get rid of germs. Use an alcohol-based hand sanitizer when you can’t wash your hands. Keep your hands away from your nose, eyes, and mouth. Cover your mouth and nose when you cough or sneeze. Always wash your hands afterward.

Influenza, or the flu, is another upper respiratory illness. Unlike a cold, which you can contract at any time of the year, the flu is generally seasonal and runs from fall to spring, peaking during the winter months.

You can catch the flu in the same way you’d pick up a cold: By coming into contact with droplets spread by someone who’s sick.

You’re contagious starting one day before you get sick and up to five to seven days after you show symptoms.

The seasonal flu is caused by influenza A, B, and C viruses, with influenza A and B being the most common. Active strains of the influenza virus vary from year to year, so experts develop a new flu vaccine every year.

Unlike the common cold, the flu can develop into a more serious condition, such as pneumonia. This is especially true for:

  • young children
  • older adults
  • pregnant people
  • people with health conditions that weaken their immune system, such as asthma, heart disease, or diabetes

Treatment

Fluids and rest are the best ways to treat the flu. Drink plenty of fluids to prevent dehydration. OTC decongestants and pain relievers may help manage some of your symptoms.

Do not give aspirin to children. It can increase the risk of a rare but serious condition called Reye’s syndrome.

Your doctor may prescribe antiviral drugs to help treat the flu.

These drugs can shorten the duration of the sickness and prevent complications. However, they may not be effective if not started within 48 hours of getting sick.

Prevention

Getting the flu vaccine is the best prevention method. It can also help make the illness less severe if you do catch it.

Most doctors recommend getting the vaccine in October or at the very start of flu season, but you can still get the vaccine in late fall or winter.

The same prevention strategies for a cold apply to the flu:

  • Be sure to wash your hands often, or use an alcohol-based hand sanitizer if you can’t.
  • Avoid touching your nose, eyes, and mouth.
  • Try to stay away from anyone who has the flu or flu-like symptoms.

Staying healthy

It’s important to adopt healthy habits to keep cold and flu germs at bay.

You should always make sure you get plenty of sleep, eat lots of fruits and vegetables, exercise, and manage your stress during cold and flu season and beyond.

If you’re at risk of complications from the flu, speak with your doctor when you first show symptoms. People at risk of serious complications include:

  • people over the age of 65
  • pregnant people
  • people who are 2 weeks postpartum
  • children under 2 years old
  • those under 18 years old taking aspirin
  • those with weakened immune systems due to HIV, steroid treatment, or chemotherapy
  • people with extreme obesity
  • people with chronic lung or heart conditions
  • people with metabolic disorders, such as diabetes, anemia, or kidney disease
  • people living in long-term care facilities, such as nursing homes

Talk with your doctor right away if your symptoms do not improve or if they worsen. Speak with your doctor if you have signs of pneumonia, including:

  • trouble breathing
  • severe sore throat
  • cough that produces green mucus
  • high, persistent fever
  • chest pain

Speak with a doctor right away if a child develops the following symptoms:

  • trouble breathing
  • irritability
  • extreme fatigue
  • refusing to eat or drink
  • trouble waking up or interacting

A cold and the flu have overlapping symptoms, which can make them hard to tell apart. Generally, symptoms of a cold come on gradually, while symptoms of the flu have a quick onset.

Prevention for a cold and the flu includes washing your hands often and keeping unclean hands away from your face, eyes, nose, and ears. The flu also has a yearly vaccine.

Some symptoms may be treatable with OTC medications, but what you’ll really need is time to recover. Speak with your doctor, however, if your symptoms worsen.