Is It Allergies or Coronavirus?

What you need to know when the slightest sniffle can be more frightening than ever

A photo of a baby covering his face with tissues that he’s taken out of a tissue box.
Photo: Cavan Images/Getty Images

EEvery year about this time, cold and flu season starts to wind down just as seasonal allergies begin ramping up, starting in warmer regions and moving northward as spring unfolds. People with pollen allergies — about 8% of U.S. adults — go through a yearly ritual of being unsure what they’ve got until several boxes of empty tissues and red, itchy eyes bring on the aha moment.

But this year, Covid-19 adds another confounding mix of symptoms to wonder and worry about. Among the differences that can help a person figure out what they might have: Allergies tend to bring the same symptoms every year, and they’re atypical for Covid-19 — runny nose and sneezing along with itchy eyes, nose, and throat. While coughing is a common symptom of moderate to severe Covid-19 cases, sneezing is not common (a study of early cases in China found nasal congestion in just 4.8% of diagnosed cases).

Dr. Robert Salata, a professor of medicine at Case Western Reserve University who is seeing Covid-19 patients at the university hospital, said he has seen “some but a small percentage” of cases involving sneezing.

“People typically are familiar with their seasonal allergy symptoms, so it’s unlikely you would mistake Covid-19 for allergy symptoms,” says Dr. Marc Goldstein, chief of allergy and immunology at Pennsylvania Hospital and head advisor at Curist, a company that curates products for allergy sufferers. “The biggest difference is fever — fever is not a symptom of seasonal allergies, but is a symptom of Covid-19.”

Still, because Covid-19 symptoms can vary in different individuals and scientists are still struggling to grasp its myriad indicators, it can be difficult to tell one from the other, or from the common cold or flu.

What allergies look like

Seasonal allergic rhinitis, often called hay fever, is the result of the immune system overreacting to plant pollen. The immune system views the allergen as an enemy, so it releases histamines, chemicals that rush to the sites where pollen gets in, including the blood vessels in and around your nose and eyes. The histamines create mucus, to make tissues swell in an effort to force the pollen out. The mucus is what runs and itches, pushing sufferers to try myriad not-always-helpful remedies ranging from antihistamines and steroid nasal sprays to salt rinses and immunotherapy.

“If seasonal allergies cause loss of smell, it’s due to extreme congestion in the nasal passage preventing odor molecules reaching the smell receptors in the roof of the nose.”

A seasonal allergy can be accompanied by other, less common symptoms. It may in some cases bring on a cough, as well as fatigue or weakness, but only rarely a sore throat. It does not cause shortness of breath. Hay fever can, however, in some cases, lead to more serious complications, including ear infections, sinusitis, or bronchitis. And hay fever can trigger asthma, which can cause shortness of breath, according to the Asthma and Allergy Foundation of America.

But hay fever will never cause an actual fever or aches and pains, according to the Mayo Clinic and other experts.

Meanwhile, identifying Covid-19 by symptoms alone has proved confounding. While fever, a dry cough, and difficulty breathing are the hallmarks of serious cases, some people infected by the SARS-CoV-2 coronavirus have had just mild cold- or flu-like symptoms. A new study, published March 31 in the American Journal of Gastroenterology, found that a few people diagnosed with Covid-19 even have had diarrhea without any other symptoms.

And based on anecdotal reports from doctors around the world, Covid-19 causes anosmia, a loss of the ability to smell things, without triggering any other symptoms.

Allergies can cause anosmia, too, but there are clear signs associated with it. “If seasonal allergies cause loss of smell, it’s due to extreme congestion in the nasal passage preventing odor molecules reaching the smell receptors in the roof of the nose,” Goldstein explains. “The loss of smell from Covid-19 is… from the virus destroying receptors and nerve fibers in the nose. Someone with Covid-19 who has anosmia will not have the other allergy symptoms, like itchiness and sneezing.”

“If individuals have allergies and they feel their symptoms have deviated significantly from what they remember of their symptoms in previous years, they should contact their doctor’s office.”

Be aware and be careful

For allergy sufferers, the bottom line is to watch for anything out of the miserable ordinary. If you have a fever, a persistent dry cough, or difficulty breathing, or diarrhea, or muscle aches, you almost surely have something besides hay fever.

“If individuals have allergies and they feel their symptoms have deviated significantly from what they remember of their symptoms in previous years, they should contact their doctor’s office,” says Dr. Sanjiv Sur, an allergist at Baylor College of Medicine.

If you have a thermometer, look for a temperature of 100.5° Fahrenheit or higher, according to this new advice on Covid-19 fevers from Kaiser Health News. Note that people have varying body temperatures, and 98.6° is no longer the accepted number for normal (so don’t assume a reading of 99.5° actually indicates fever, for example).

If you don’t have a thermometer (they’re reportedly in short supply these days) the Kaiser article advises looking for chills, sweats, or body aches — all telltale signs of fever.

Meanwhile, if seasonal allergies strike, heighten your awareness of common habits to avoid becoming seriously ill. “People with unmanaged seasonal allergies are constantly touching their nose and eyes,” Goldstein points out. That puts a person at greater risk for getting Covid-19, given that the virus can be transmitted by infected hands touching those entry points to the body.

Common treatments for seasonal allergies include antihistamines, which aim to prevent histamines from anchoring, and steroid nasal sprays, which reduce inflammation. For allergy prevention, health experts suggest:

  • Close windows and doors.
  • Stay inside when pollen counts are highest, typically from 5 a.m. to 10 a.m. or on hot, windy days.
  • Shower after being outside.
  • Change bedding frequently.

Goldstein also offers some relatively good news. Unlike other underlying health conditions that raise the risk of severe Covid-19 symptoms, including heart disease, diabetes, and asthma, “seasonal allergies in themselves do not put you at greater risk of contracting Covid-19 or suffering more severe symptoms.”

Independent health and science journalist, former editor-in-chief of LiveScience, writing about how we age and how to optimize your mind and body through time.

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