A doctor explains: how to tell if it’s hay fever or coronavirus

As spring moves into summer in the Northern hemisphere, millions of people will experience the familiar sneezing, runny eyes and itchy throat that signals the air is thick with pollen and the annual blight of hay fever is back.

But with cases of coronavirus still rising around the world, there’s concern from some that the symptoms of COVID-19 may be dismissed as hay fever. In the UK, for example, professional membership body the Royal College of General Practitioners has warned people of the similarities between the two.

Hay fever, also known as allergic rhinitis, affects between 10% and 30% of the global population each year. It’s caused by an allergic response to pollen and mold and you can get it at any age.

Here, Dr. Kate Tulenko, physician and CEO of Corvus Health, a global health workforce services firm, explains how to know whether it’s hay fever or coronavirus.

What is hay fever?

Hay fever is an allergic response triggered by very specific types of mould and pollen. For example, in the US, it's mainly ragweed pollen, and in the UK mainly Timothy and rye grass pollen. The immune reaction releases histamine which makes all the blood vessels leaky, so there’s all this water in your eyes and in your nose, which is what gives people puffy eyes and makes them sneeze.

Why might people confuse the symptoms of COVID-19 and hay fever?
People are starting to call COVID-19 one of the great masqueraders...In an average case of flu, you get a runny nose, cough and body aches. Just two systems are involved: your respiratory system and your musculoskeletal system. But COVID can cause many symptoms affecting different organs and systems, so the challenge is it can look like anything.

One study in China showed that a third of patients with COVID-19 had eye-related symptoms. So it’s a real possibility people might confuse it with hay fever.

As a result, doctors will have to test everyone who has symptoms for COVID to make sure they're not missing it. If they come in with diarrhoea, they’re tested for COVID, if someone comes in with watery eyes, you test them for COVID. The risk of missing it is so great, both from the perspective of them infecting other people and also to get them the right treatments.

What other similarities exist?
There can be overlap with COVID symptoms because of direct infection causing inflammation. And because COVID causes a lot of people to have fluid overload because it can damage the kidneys and reduce the urine output. If people have fluid overload, that's going to make all your mucosa leaky, including your nose mucosa and your eye mucosa.

How can doctors confirm that patients have hay fever?
Physicians can relatively easily tell the difference by looking into your nose and seeing symptoms of the allergic reaction [related to hay fever]. Also they can do a nasal swab and look for a type of cell called eosinophils which is the immune cell responsible for allergic reaction.

If you’re more prone to certain symptoms, will you get those with COVID-19?
I haven't seen any data on that for COVID-19. But it certainly aggravates chronic conditions, so someone with COVID with asthma is probably going to have a worse cough than someone without asthma. We can definitely say that if you have a chronic disease that affects a certain organ system, you are probably going to have worse symptoms in that organ system with COVID than a person without that chronic disease.

If you have hay fever symptoms, what should you do?
My advice for someone who has had hay fever in the past is, if they start to get symptoms they should think, ‘is it the time of year I normally get the symptoms?’ and start taking their hay fever medication. If it goes away, it means it's probably hay fever. But if it doesn’t, they should seek out further help.

Hay fever tends to be more focal - on the eyes and the nose. So if you’re having systemic symptoms, like fatigue or fever or body aches, it's probably not hay fever.

Should people with hay fever take any additional precautions?
They should always talk to their physician first, but a lot of physicians are now recommending hay fever sufferers do a nasal saline wash when they’ve been outside because that gets the allergens out of the nose. And they usually say [to] take off your overcoat, change your clothes and wash the allergens off of you. They also recommend people change their pillowcase more often.

But [hay fever sufferers] are also at much higher risk to actually give themselves COVID because they're touching their eyes all the time. I have heard some people recommending if you don't wear glasses, just wear a pair of non-prescription glasses or a pair of safety goggles. By having that physical barrier there, it'll keep you more aware and hopefully help avoid you touching your face. But it’s a really hard habit to change.

When should hay fever sufferers consider being testing for COVID-19?
Unfortunately, for the next six months, when people are sick, they probably should seek COVID testing because it can imitate so many different diseases. So someone who hadn't had hay fever before and suddenly seems to be getting it should definitely be tested for COVID.