Differences Between Seasonal Allergies and COVID-19

Allergies vs. COVID-19, Colds, and Flu: Overview

Allergies vs. cold: itchy eyes and sneezing point to allergies, which are an immune reaction and aren’t contagious, while a cold is a viral infection. Hay fever also doesn’t cause a fever (ACAAI). The full comparison of allergies vs. cold, flu and COVID-19 is below.

Sneezing, a sore throat and a stuffy nose? It could be seasonal allergies, a cold, the flu or COVID-19. All four share many symptoms, and COVID-19 is now one of several respiratory viruses that circulate every year. This guide compares them side by side so you can decide what to do next.

The key difference is the cause. Colds, flu and COVID-19 are infections caused by viruses and can spread to others. Seasonal allergies are an immune reaction to things like pollen and mold; they are not contagious and never cause a fever (ACAAI). The only way to know for sure whether you have COVID-19 is to test (Mayo Clinic).

What Is COVID-19 and What Are Its Symptoms?

COVID-19 is a respiratory disease caused by the SARS-CoV-2 virus. It mainly spreads between people in close contact through droplets released when an infected person breathes, coughs, sneezes, talks or sings. Many people have mild illness, but it can be serious for some. Today the most common symptoms are a runny or stuffy nose, headache and sore throat, which is why it’s easy to confuse with allergies or a cold (Mayo Clinic).

COVID-19 Symptoms

• Runny or stuffy nose
• Headache
• Sore throat
• Tiredness
• Cough (often dry)
• Fever or chills
• Muscle aches
• New loss of taste or smell
• Nausea, vomiting or diarrhea
• Shortness of breath

COVID-19 symptoms usually start 2 to 14 days after exposure (Mayo Clinic). If you have symptoms, an at-home test is a quick first step. Seek emergency care right away for warning signs like trouble breathing or chest pain (CDC).

What Are Seasonal Allergies and Their Symptoms?

Seasonal allergies, also called hay fever or allergic rhinitis, happen when your immune system overreacts to airborne pollen from trees, grasses and weeds or to outdoor mold spores. They are not caused by a virus, are not contagious, and do not cause a fever (ACAAI). About one in four U.S. adults (25.7%) report a diagnosed seasonal allergy (CDC).

Seasonal Allergy Symptoms

The common symptoms of seasonal allergies are as follows:

• Itchy nose, eyes, mouth or throat
• Sneezing
• Runny or stuffy nose
• Red, watery or puffy eyes
• Cough or postnasal drip
• Tiredness, often from poor sleep
• Reduced sense of smell from congestion

Allergies usually don’t cause shortness of breath unless you have a condition like asthma that pollen can trigger (Mayo Clinic). See our page on seasonal allergies vs. asthma for more.

How to Tell Allergies, COVID-19, Colds, and Flu Apart

Symptoms overlap a lot, so no checklist can replace a test. This comparison, based on Mayo Clinic, shows typical patterns. (A dash means Mayo Clinic doesn’t list that symptom for that illness.)

Symptom	Allergies	COVID-19	Cold	Flu
Fever	Never	Sometimes	Rarely	Usually
Itchy eyes, nose or mouth	Usually	Sometimes	—	—
Sneezing	Usually	Sometimes	Sometimes	Sometimes
Runny or stuffy nose	Usually	Usually	Usually	Usually
Sore throat	Sometimes	Usually	Usually	Usually
Headache	Rare	Usually	Rarely	Usually
Muscle aches	Never	Sometimes	Never	Usually
Tiredness	Sometimes	Usually	Never	Usually
Cough	Sometimes	Sometimes (dry)	Sometimes	Usually
New loss of taste or smell	Sometimes	Sometimes (early)	Never	Rarely
Shortness of breath	Sometimes (with asthma)	Sometimes	Never	Sometimes

Fever and body aches point to an infection. Allergies never cause a fever. Flu typically brings fever, body aches and fatigue, often suddenly; a cold is usually milder (Mayo Clinic).

Itching points to allergies. Itchy eyes, nose and mouth are hallmark allergy symptoms. Allergy symptoms also follow exposure: they flare when pollen is high or you’re outdoors and continue as long as exposure continues, while a cold usually runs its course in a few days to a week (ACAAI).

Timing helps too. Cold symptoms usually appear 1 to 3 days after exposure, flu 1 to 4 days, and COVID-19 2 to 14 days. Seasonal allergies can last for weeks and tend to return at the same time each year (Mayo Clinic).

Do Allergies Cause a Fever?

No. Despite the name, hay fever doesn’t cause a fever (ACAAI). If you have a fever along with congestion or a sore throat, an infection such as a cold, flu, COVID-19 or a sinus infection is more likely, so consider testing and talk with your doctor if symptoms are severe or don’t improve.

Do Allergies Make You More Likely to Get Sick?

Allergies don’t give you a cold, flu or COVID-19, since those are caused by viruses. But allergy symptoms can make it harder to notice when you’ve also caught something. If you have asthma, keeping allergies under control matters, because uncontrolled allergies can make asthma worse (FDA).

Can You Have Allergies and a Virus at the Same Time?

Yes. You can have seasonal allergies and catch a cold, the flu or COVID-19 at the same time, and you can even have COVID-19 and flu together (Mayo Clinic). A clue is a change in your usual pattern: new fever, body aches or fatigue, or symptoms that don’t respond to your normal allergy medicine.

If you think you have a respiratory virus, current CDC guidance is to stay home and away from others, and return to normal activities once your symptoms have been improving overall and you’ve been fever-free without fever-reducing medicine for at least 24 hours. Then take extra precautions for the next 5 days (CDC).

Conclusion

Allergies, colds, flu and COVID-19 can look alike, but fever, body aches and itching are useful clues. Allergies respond to antihistamines, nasal steroid sprays and avoiding triggers; viral illnesses usually need rest, and testing helps confirm COVID-19 or flu. Talk to a healthcare provider if symptoms are severe, unusual or not improving. For seasonal triggers, see spring allergies and fall allergies.

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Written by: Madiha Ather Hashmi (April 27, 2022)

This article is for general education and is not medical advice. Talk with your doctor or pharmacist about your symptoms and before starting, stopping, or combining any medicine.

Allergies vs. COVID-19, Colds, and Flu FAQs

Can allergies cause a fever?

No. Hay fever does not cause a fever. A fever suggests an infection like the flu or COVID-19 (ACAAI).

Can allergies cause loss of smell?

Sometimes, usually from congestion. A sudden new loss of taste or smell without a stuffy nose is more suggestive of COVID-19 (Mayo Clinic).

How do I know if it’s COVID-19 or allergies?

Testing is the only way to know for sure. At-home COVID-19 tests are a convenient first step (Mayo Clinic).

When can I go back to work or school after a respiratory virus?

CDC advises waiting until symptoms are improving overall and you’ve been fever-free for 24 hours without medicine, then taking extra precautions for 5 days (CDC).

Sources

Looking for more allergy types? Find a full list of other allergy causes here.