Omicron, Flu, Allergies: How Can You Tell the Difference in Symptoms?

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If you're wondering whether that runny nose, sore throat or sneeze is simply allergies, just a cold, or possibly early signs of COVID-19 or the flu, you're not alone.

With many experiencing cold-like symptoms, and with COVID and flu cases rising this winter, it can be hard to decipher what could be behind the onset of symptoms.

Experts say the only real way to know the answer is to test, but until then, health officials say to treat any possible symptoms as COVID.

"If you think it's a cold, if you think it's the flu, it's probably COVID," Chicago Department of Public Health Commissioner Dr. Allison Arwady said in a press conference late last month. "We need you to stay home if you're not feeling well."

Arwady said that now, particularly with the rise of omicron cases, those who are fully vaccinated against COVID aren't necessarily getting "seriously ill and having fevers for days and difficult breathing," but are instead experiencing a more mild illness.

"They may only feel like they have a cold," she said. "That's good because they're not getting seriously sick, they're not threatening the healthcare system, but it's certainly of some concern because they do have the potential to transmit to others."

Doctors have reported some cases of what's being called "flurona," or a dual infection of both COVID and the flu at the same time. But according to Dr. Mark Loafman, chair of family and community medicine for Cook County Health, there's no clear way to tell the difference between COVID or flu - and no real way to tell if you have both.

"We're making most of those diagnoses clinically," he said.

In hospital settings, testing "for not just COVID but for the whole respiratory panel" are increasing across the Chicago area, Loafman said, but testing for such cases is only done when a patient is sick enough to need medical care.

While the symptoms are nearly identical, there can be subtle differences, Loafman said.

"One thing is the fever with flu, with influenza, tends to be a little higher, but that's subtle," he said. "So 101, 102 [degree] fever can happen with COVID, the fever can get a little higher with flu but it can also be low-grade. So other than that, you know, coughs, headaches, stuffy nose... congestion, some shortness of breath - those are all very, very common for both flu and COVID and I think for most of us, we wouldn't really be able to tell the difference."

Sore throat continues to be a symptom reported, particularly in mild breakthrough infections, Arwady said during a Facebook Live last week.

"Especially in people who we're seeing these more mild breakthrough infections, we are definitely seeing sore throat be a predictor in that group," Arwady said.

She repeated earlier calls for people who have any flu- or cold-like symptoms to assume they have COVID "until proven otherwise."

"Even if it's a sore throat, no matter what it is," she said. "I've told my own staff this, it's what I do myself... if you are sick, even a little bit sick, stay home. More true than ever right now because sick, even a little bit sick, until proven otherwise with a test - that's COVID. That's how we treat it, that's how you should treat it."

Dr. Katherine Poehling, an infectious disease specialist and member of the Advisory Committee on Immunization Practices, told NBC News last week that a cough, congestion, runny nose and fatigue appear to be prominent symptoms with the omicron variant. But unlike the delta variant, many patients are not losing their taste or smell.

The evidence so far, according to Poehling, is anecdotal and not based on scientific research. She noted also that these symptoms may only reflect certain populations.

Still, CDC data showed the most common symptoms so far are cough, fatigue, congestion and a runny nose.

Symptoms as Listed by the CDC

Overall, the symptoms for COVID reported by the CDC include:

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

"This list is not all possible symptoms," the CDC states. "Please call your medical provider for any other symptoms that are severe or concerning to you."

The CDC also has what it calls a "coronavirus self checker" that allows people to answer a series of questions to determine if they should seek medical care.

"The Coronavirus Self-Checker is an interactive clinical assessment tool that will assist individuals ages 13 and older, and parents and caregivers of children ages 2 to 12 on deciding when to seek testing or medical care if they suspect they or someone they know has contracted COVID-19 or has come into close contact with someone who has COVID-19," the CDC's website reads.

Here's how to use it.

The CDC urges those who have or may have COVID-19 to watch for emergency warning signs and seek medical care immediately if they experience symptoms including:

  • Trouble breathing
  • Persistent pain or pressure in the chest
  • New confusion
  • Inability to wake or stay awake
  • Pale, gray, or blue-colored skin, lips, or nail beds, depending on skin tone

You can also notify the operator that you believe you or someone you are caring for has COVID.

For the flu, the CDC lists the following symptoms:

  • fever or feeling feverish/chills
  • cough
  • sore throat
  • runny or stuffy nose
  • muscle or body aches
  • headaches
  • fatigue (tiredness)
  • Some people may have vomiting and diarrhea, though this is more common in children than adults

For allergies, the CDC notes that some people may experience symptoms of rhinitis and conjunctivitis. Those symptoms include:

  • Symptoms from allergic rhinitis include:
    • sneezing
    • runny nose
    • congestion
  • Symptoms from allergic conjunctivitis include:
    • red, watery, or itchy eyes
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