Is This a Cold, Flu or Allergies?

As the temperatures drop, we spend more time indoors, allowing us to share germs more easily. Close contact puts us in each other’s “breathing zone,” which is the three to six-foot radius that facilitates the spreading of respiratory viruses. In addition to increased opportunities for germ-sharing, there are other reasons for sickness to spike in winter. Studies show that the season’s cold, dry weather keeps viruses suspended in the air longer than other conditions. Other studies show that our immune systems are more vulnerable in cold months.

Cold, Flu or Allergies

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Regardless of the reason for winter’s increased illness, it’s important to know how to identify what your body is experiencing and when you need to get help. Here’s a look at the differences between the common winter illnesses of cold and flu.


Colds are caused by viruses, including the rhinovirus, which is particularly common in winter. Cold viruses can spread when infected people cough, sneeze, or speak. They can then enter the body through the nose, eyes, or mouth.

Colds usually rev up with a sore throat, which is followed by a runny nose, congestion, and coughing. Mucus can become thicker and darker as a cold progresses. Fevers can occur with colds, but they are less likely.

You are typically contagious for the first three days of a cold, so stay home to keep from infecting others. Rest up and stay hydrated. Colds usually only last about a week, so if you’re not improving by the time one week is up, see a physician. You may have developed a bacterial infection and need antibiotics.

Since colds are caused by viruses, you can’t treat them, but you can soothe your symptoms with nasal sprays, antihistamines, and decongestants.


Flu may manifest with the same symptoms as a cold, but it could also include fever, headache, muscle aches, a bad cough, and even vomiting and diarrhea.

If you have the flu, you may be contagious for up to four days. Flu symptoms tend to last longer than cold symptoms, and may endure for a week or more. You should talk to your doctor if you experience shortness of breath or a recurring fever, as your flu may have progressed into pneumonia.

Like colds, the flu is also caused by a virus. The best thing that you can do for flu is to rest and get plenty of liquids. You can treat your symptoms using pain relievers and fever reducers as well as cold and cough medications. Your doctor may prescribe antiviral drugs for your flu.


If you find that you experience cold-like symptoms, include a runny or congested nose or a cough, for more than a couple weeks, you may have allergies. While most people complain of allergies in fall and spring, there are allergens in the environment in winter that can trigger symptoms. If you suspect that you are suffering from allergies, contact your sublingual immunotherapy doctor at AllergyEasy for information about a no-hassle alternative to allergy shots that can be taken as allergy drops under the tongue.

About The Author

Stuart H. Agren, M.D.

Stuart H. Agren, M.D. completed his undergraduate studies at the University of Utah and went on to earn his Doctor of Medicine from Tulane University School of Medicine in 1974. He completed additional training at L.D.S. Hospital in Salt Lake City, Utah and then established his private medical practice starting in 1975. Dr. Agren completed a mini-residency in Industrial Medicine at the Robert Johnson School of Medicine at Rutgers University and also completed training to become a certified Medical Review Officer.

Dr. Agren was the Medical Director at TRW and McDonnell Douglas in Mesa, Arizona and at Stauffer Chemical and Kennecott Copper in Salt Lake City, Utah. He also served as an adjunct faculty member at Arizona State University.

In his private medical practice, Dr. Agren specialized in family practice and allergy. In his work as a private practice allergist, he was one of the first doctors in the country to prescribe sublingual immunotherapy to his patients as an alternative to subcutaneous immunotherapy (allergy shots). He has also been a trailblazer in the field of food allergy treatment and research, developing a program to treat multiple food allergies simultaneously using sublingual immunotherapy. Dr. Agren has been featured on local CBS, NBC, and ABC news affiliates and won the peer-nominated “Top Doc” award from Phoenix Magazine.

After 20 years in private practice, Dr. Agren became the Founder and President of AllergyEasy, which helps primary care physicians around the country offer allergy testing and sublingual immunotherapy treatment to their patients. Over 200 physicians in over 32 states use the AllergyEasy program to help their patients overcome environmental and food allergies and asthma.