A runny or stuffy nose can be a symptom of the flu, a cold or allergies, and it can be hard to discern which one you have. So how do you know what’s really going on with your nose?

“More than likely the problem is probably being caused by a virus, especially if there is a defined start date of symptoms, but if your runny nose or congestion is lingering, it could be allergies,” said Isabel Valdez, a physician assistant and instructor of family and community medicine at Baylor College of Medicine. “If your runny nose is accompanied by a fever or body aches, then you might have the flu.”


A big indicator that a person might have the flu is when symptoms such as body aches, fevers, chills, nausea, an upset stomach or night sweats suddenly start occurring, Valdez said. Usually high fever, above 101 degrees, signals that you might have the flu. Also, there is a finite ending to having the flu, and you should be done experiencing symptoms after about one to two weeks.

Valdez emphasized that getting the flu shot is an extremely important step to take to protect yourself from contracting the flu.

“The flu shot is there to protect you. You want to get the flu shot so that you can launch an immune response to the real infection if you are exposed to the flu,” she said. “Also, if you do contract influenza, it will hopefully help you get over the illness quicker.”


Valdez explained that a big difference between the flu and a cold is that a cold will most likely not give you a high fever and/or body aches. Fevers signaling a cold are generally low-grade, between 99 and 100 degrees. These fevers also do not typically last as long in someone who has a cold as opposed to the flu. In addition, a cold or a virus operates on a schedule, which means people will typically have a sore throat at the beginning, then they get congestion for a few days, and then as the congestion starts to clear, they develop a cough that lasts for a few days.

One myth that Valdez said people should know about is that mucus color does not necessarily signal an infection.

“Everybody thinks that if they have green mucus, they need an antibiotic but that’s not necessarily the case. A lot of the time, you can start the day with yellow-green mucus when you have a virus but as long as that mucus gets lighter in color and thinner in consistency as the day progresses then you don’t need antibiotics.”


A signal that you have allergies is when your mucus is clear as opposed to yellow or green, Valdez said. The mucus also tends to be a little bit runnier.

Changes in weather can bring on allergies since there are more irritants in the environment that people may come in contact with, she said. These irritants might cause mild allergies with symptoms including a stuffy nose, scratchy throat or feeling pressure around the eyes. Mild allergies can be taken care of with over-the-counter allergy medications, antihistamines and nasal sprays.

Valdez added that exposure to excessive heat can cause issues with your nose. If you are exposing your nose to too much heat, like when the heater is running nearly continually during cold weather, the heat can dry out the mucosa in your nostrils, causing irritations. Excessive exposure to heat also can cause the mouth and throat to feel dryer because the heat is soaking up moisture that the body needs. 

“Sometimes if people dry out their noses too much, this can lead to them having little nose bleeds or when they blow their nose they will notice blood in the mucus and, again, this is because the mucosa inside their nostrils gets so dry and fragile from the heat that little blood vessels will pop,” Valdez said. “Usually if this happens, I recommend that patients start to use a nasal saline spray to moisturize their nostrils.”