AllergyNest

Cold or allergies?

Answer a few questions about your symptoms and see whether they have more in common with a cold or with allergies, with a source for every reason.

Editor: Ara OhanianUpdated

Call 911 if someone

  • Is short of breath, wheezing or coughing, or has a tight chest
  • Has a tight throat or trouble swallowing
  • Has swelling of the lips, tongue or the back of the throat
  • Feels dizzy, faints or has a weak pulse

These can be signs of anaphylaxis, a serious allergic reaction that can begin very quickly. If someone is having a serious allergic reaction, call 911.

Based on MedlinePlus on anaphylaxis. General information, not medical advice.

Answer a few questions

Your answers stay in your browser. We don’t receive or keep them.

  1. Do you have a fever?
  2. Do you have general aches and pains?

    Such as sore muscles or an achy feeling all over.

  3. Do you have a sore throat?
  4. Are your eyes itchy and watery?
  5. Have your symptoms lasted more than 2 weeks?

    Count from the day your symptoms began.

  6. Do your symptoms come back at about the same time each year?

    For example, every spring.

  7. Did your symptoms start soon after you were around pollen, a pet, dust or mold?

    For example, after time outdoors, or after visiting a home with a cat or dog.

  8. Were you around someone with a cold in the days before your symptoms began?

What this can’t tell you

This tool compares your answers with what a few health sources say. It isn’t a diagnosis, and it can’t examine you or run a test.

Colds, flu and allergies can be hard to tell apart because they share so many symptoms.1 Colds and flu can both lead to a runny, stuffy nose, congestion, cough and sore throat.1 CDC says the viruses that cause COVID-19, flu and RSV can also cause cold-like symptoms, though they don’t cause colds.3 It says to get tested if you have cold-like symptoms and suspect COVID-19 or flu, especially if you’re at higher risk for severe illness.3 CDC also lists seasonal allergies and colds among the conditions that can cause symptoms similar to a sinus infection.5

An NIH expert explains that allergies aren’t caused by a virus: they are the body’s immune system reacting to a trigger, or allergen, which is something you’re allergic to.1 For hay fever, MedlinePlus says a health care provider may make the diagnosis based on a physical exam and your symptoms, and that skin or blood tests are sometimes used.9

When to see a doctor

On its page about managing colds, CDC says to seek medical care if you or your child has trouble breathing or fast breathing, dehydration, a fever that lasts longer than 4 days, symptoms that last more than 10 days without getting better, symptoms such as fever or cough that improve then return or worsen, or chronic medical conditions that get worse.4 CDC notes that this list is not all-inclusive and says to see a healthcare provider for any symptom that is severe or concerning.4 It also says to contact a healthcare provider right away, even if the illness is mild, if you or your child has symptoms of a respiratory virus and is at higher risk of severe illness from COVID-19 or flu.4

For allergies, ACAAI says you should see an allergist if you have hay fever or other allergy symptoms several months out of the year, or if allergies interfere with your day-to-day activities or decrease your quality of life.8

How the answer is worked out

Each question offers yes, no and not sure. When the sources tie an answer to a cold or to allergies, that answer adds a reason to that side, shown with its source. “Not sure,” and answers the sources don’t tie to either side, add nothing. The result says which side has more reasons, or that your answers point both ways or neither. Every reason counts the same, however strong the symptom. Your answers stay in your browser; AllergyNest doesn’t receive or keep them.

Read more on AllergyNest

Questions

Can allergies cause a fever?

Hay fever does not, ACAAI says, despite its name. With a cold, it says, you may have a low-grade fever.6

Are allergies contagious?

No. NIH News in Health says allergies can cause a runny nose and sneezing, but they’re not contagious.2

How long does a cold last?

Usually less than a week, CDC says. The signs and symptoms of a cold usually peak within 2 to 3 days of infection.3

How long do allergy symptoms last?

Usually as long as you’re exposed to the allergen, NIH News in Health says, which may be about 6 weeks during pollen seasons in the spring, summer or fall. Colds and flu rarely last beyond 2 weeks.1

Does the color of mucus tell a cold from allergies?

ACAAI says a runny nose from hay fever will likely have a thin, watery discharge, while a cold may bring a thicker or yellowish one. It also says it can be difficult to tell the difference between a cold and hay fever.6

Sources

  1. Cold, Flu, or Allergy?. NIH News in Health, National Institutes of Health. Read on October 17, 2026.
  2. Is It Flu, COVID-19, Allergies, or a Cold?. NIH News in Health, National Institutes of Health. Read on October 17, 2026.
  3. About Common Cold. Centers for Disease Control and Prevention. Read on October 17, 2026.
  4. Manage Common Cold. Centers for Disease Control and Prevention. Read on October 17, 2026.
  5. Sinus Infection Basics. Centers for Disease Control and Prevention. Read on October 17, 2026.
  6. Hay Fever (Rhinitis). American College of Allergy, Asthma and Immunology. Read on October 17, 2026.
  7. What are the symptom differences between the cold, flu and allergies?. American College of Allergy, Asthma and Immunology. Read on October 17, 2026.
  8. When To See an Allergist. American College of Allergy, Asthma and Immunology. Read on October 17, 2026.
  9. Hay Fever. MedlinePlus, National Library of Medicine. Read on October 17, 2026.

Ara Ohanian, editor. Parent of two children with allergies. Seven years working with US allergy clinics and allergists on growth, patient outreach and allergy data.

Drafted with AI help from the sources above, then checked against them in a separate AI fact-check pass. How we write these pages. Not reviewed by a clinician. General information, not medical advice.