Cold vs Flu vs COVID vs Allergies

Allergy, cold, flu and COVID symptoms can be similar. Understanding their key differences can get you on the road to recovery faster.

We’ve all been there. You wake up with a sore throat, then come the aches and the congestion that feels like it may cause your head to explode.

Is it a cold or allergies? Or something worse, like the flu — or even COVID? Should you see your healthcare provider or just stay home and rest?

“Viruses that affect the respiratory tract spread in similar ways and can cause any of these illnesses — with the exception of allergies. The others are all contagious and share similar symptoms, so it can be difficult to differentiate between them,” says Cynthia Ciccotelli, MD, a primary care physician at Geisinger Buckhorn. “But, it’s important to understand key differences in symptoms to get the right treatment and slow the spread.”

Let’s take a look at how to spot the difference between allergies vs cold vs flu vs COVID to get you on the road to recovery ASAP.

Seasonal allergy symptoms

Seasonal allergy symptoms range in severity, can be stronger at certain times of the year and aren’t contagious.

“For example, someone who has allergies may have their worst symptoms during the summer months, when it’s hotter and plants and grasses pollinate,” says Dr. Ciccotelli. “Others may be affected by normal things in their environment — think dust, pet dander and mold.”

Seasonal allergy symptoms can include:

Sneezing
Itchy or watery eyes
Itchy nose, ears or throat
Cough or a tickle in the throat
Stuffy or runny nose
Hives
Swelling

While allergies can be treated at home with over-the-counter or prescription antihistamines, decongestants and nasal steroid sprays, some allergies may require special treatment from your doctor.

If you think you may have allergies, talk with your doctor about your symptoms and the best treatments to find fast relief.

Common cold symptoms

Cold symptoms come on gradually and are milder than symptoms of the flu and COVID. Common cold symptoms typically include:

Cough
Mild fever (more common in children)
Stuffy or runny nose with sinus tenderness or fullness
Ear discomfort or pressure
Sneezing
Sore throat
Headache
Fatigue

A key symptom differentiator is sneezing, which is usually more associated with the common cold or allergies than with the flu or COVID. And a person with a cold rarely has muscle aches. Plus, a cold never causes vomiting or diarrhea.

Common cold symptoms typically last for about 7 to 10 days. However, you’re usually only contagious during the first few days, and it’s best to practice good hand hygiene and limit close contact with others during that time.

“Most colds are caused by a virus, which antibiotics won’t treat. It’s best to get plenty of rest, fluids and use over-the-counter medicines to help manage symptoms,” says Dr. Ciccotelli. “But if you’re struggling with symptom management, talk to your primary care provider. We have a few tricks up our sleeve that can help you.”

If your symptoms last longer than 2 weeks, check with your healthcare provider to rule out an allergy or bacterial infection.

Flu symptoms

Flu symptoms are often severe and come on quickly. If you have a fever and body or muscle aches right away, you may have the flu virus. Flu symptoms commonly include:

Body aches and chills
Chest discomfort
Cough
Extreme tiredness/fatigue
Headache
High fever
Sometimes nausea and diarrhea

Most flu symptoms improve over the course of a few days, but you’ll likely feel run down for a week or two. The flu is caused by the influenza virus, which leaves you contagious for a few days, so it’s important to stay home and rest.

“While a cold and the flu have similar symptoms, the flu is much more severe and, though rare, can result in complications like pneumonia, especially in people who are young, elderly or have chronic heart or lung problems,” says Dr. Ciccotelli. “Ask your doctor if the flu and pneumonia vaccines are right for you to help prevent serious complications.”

As with the common cold, antibiotics won’t help your flu symptoms, but getting rest, fluids and using over-the-counter medicines can help ease them.

Your healthcare provider may prescribe an antiviral medication, which can help you feel better sooner and may prevent complications like pneumonia.

COVID symptoms

Like the flu, COVID is a respiratory illness, but it’s caused by a different virus. COVID symptoms can range from mild to severe and may include:

Fever and chills
Muscle or body aches
Cough
Shortness of breath or difficulty breathing
Congestion or runny nose
New loss of taste or smell
Sore throat
Fatigue
Headache
Nausea or vomiting
Diarrhea

A key difference between COVID and the flu is COVID’s unique symptom: changes in or complete loss of taste and smell. Also, COVID typically produces a dry cough.

Even so, it can be hard to tell the difference between COVID and the flu based on symptoms alone. Take an at-home COVID test if you’re not sure what’s causing your discomfort. If you test positive, call your doctor. Compared to the flu, COVID can cause more serious complications.

“It’s important to identify positive cases of COVID, so we can take proactive measures in protecting our communities,” says Dr. Ciccotelli.

Tips to prevent the common cold, flu and COVID

Like most respiratory viruses, the common cold, flu and COVID can spread person-to-person through respiratory droplets when an infected person coughs or sneezes.

While most symptoms of these viruses resolve after drinking plenty of fluids and getting rest, that’s not always the case. That’s why prevention is the best medicine.

Dr. Ciccotelli offers these recommended measures to protect yourself and others against these viruses:

Wash your hands frequently using warm, soapy water for at least 20 seconds. If a sink isn’t available, use an alcohol-based hand sanitizer.
Get vaccinated against the flu and COVID.
Cover coughs and sneezes with a tissue or the inside of your elbow.
Avoid touching your eyes, nose and mouth.
Disinfect frequently touched surfaces in your home, such as doorknobs, light switches and countertops.
Avoid contact with people who are sick. And if you become sick, stay home to keep from infecting others.

“If you’re not sure what’s causing your discomfort, always talk to your doctor,” says Dr. Ciccotelli. “These viruses cause similar symptoms but require different treatments. And sometimes a person can be infected with multiple respiratory viruses at once. That can cause more severe illness or complications, especially in older adults, young children and those with certain medical conditions.”