Is It a Cold, or Is It Allergies?

When flowers are in bloom and cold viruses are circulating in the spring, it can be challenging to tell whether symptoms like sneezing, coughing and a runny nose are the result of a cold, allergies or both.

In the United States, about a quarter of adults deal with seasonal allergies, according to the Centers for Disease Control and Prevention. And every adult gets an average of two to three colds per year, typically in the winter and spring.

Understanding what’s causing your symptoms is crucial for effective treatment, experts say. The good news is that there are some simple ways to tell colds and allergies apart.

Signs that you have a cold (or another viral illness)

Many viral infections like the common cold cause symptoms that are slightly different from those caused by seasonal allergies, said Dr. Joyce Yu, a pediatric allergist immunologist at Columbia University Irving Medical Center.

Fever. While most adults and older children have no fever (or a low fever) when they’re sick with a cold, a fever is a “definite red flag” that you have some sort of viral infection, Dr. Yu said. It could be a cold or another illness, like the flu or Covid-19.

But, Dr. Yu said, a “fever never occurs with allergies,” so you can always rule that out.

Body aches. If your muscles feel painful, sore, achy or fatigued, then that discomfort is probably caused by a cold (or another viral illness) rather than allergies, Dr. Yu said.

This is more than just feeling a little tired, she added. “If you feel like a truck has run over you, that may be more because you’re sick” with an infection, she said.

Sore throat. Allergies can cause irritation in your throat via postnasal drip, said Dr. Jyothi Tirumalasetty, a clinical assistant professor of medicine at Stanford University who specializes in allergy and immunology. But a sore throat is more typical with a cold, especially if it is more painful.

If your tonsils are also red or swollen, that’s another sign that you have a cold (or another viral infection), she said.

Severe cough. A cough may come from a cold or allergies, Dr. Tirumalasetty said, but when it is caused by a cold, it’s typically more severe. If a coughing fit is so bad that it wakes you up in the middle of the night, for example, that’s a sign of a cold, she said.

With a cold, it’s possible to have a wet, phlegmy cough or a dry cough, but with allergies, it’s typically dry.

One exception to the severity rule, though, is if you have asthma in addition to your allergies, Dr. Tirumalasetty said. In that case, your allergies could trigger asthma symptoms, which may include a lot of coughing and wheezing.

Signs that you have seasonal allergies

Clear mucus. A runny nose with clear snot might suggest that you are experiencing allergies rather than a cold.

When you have a cold, Dr. Yu said, the mucus in your nose tends to be thicker and more yellow or green. The thickness can also make you feel congested.

With allergies, the mucus in your nose is more likely to be thinner and runnier, which makes it appear clear.

But these are all generalizations, Dr. Yu said.

Itchiness. If you find yourself wanting to scratch your skin, especially around your eyes, nose and ears, that’s a sign that you are experiencing symptoms from allergies rather than a cold, Dr. Yu said.

Red or watery eyes and puffy eyelids are also more typical of allergies than of colds, Dr. Tirumalasetty said.

Sneezing. Sneezing is a tricky symptom, Dr. Yu said, because it’s common with both allergies and colds. But, unlike with allergies, sneezing is not the predominant feature of a cold. So if you’re sneezing a lot but you don’t feel sick with a sore throat, body aches, fatigue or other common cold symptoms, that could be a sign of allergies.

Timeline of symptoms

With spring seasonal allergies, which are mostly caused by tree pollen, you’ll probably experience a slow, smooth build in your symptoms over a few weeks as trees release more pollen, Dr. Tirumalasetty said.

But with a viral infection like a cold, Dr. Yu said, your initial symptoms typically develop over just a few days.

And in most cases, all of your cold symptoms will resolve within a couple of weeks, Dr. Tirumalasetty said, whereas symptoms of seasonal allergies can last for an entire season.

If you notice that you get allergy symptoms around the same time every spring, it’s safe to assume that your current symptoms are at least in part because of allergies, said Dr. Shradha Agarwal, an allergist immunologist at the Icahn School of Medicine at Mount Sinai in New York City — unless your current symptoms differ greatly from your usual ones.

If you think you have a cold and you’re not feeling better after a week or two, Dr. Tirumalasetty said, see a doctor or an allergist to assess whether you have allergies or some other condition like a sinus infection.

What to do

Some over-the-counter treatments can help with both cold and allergy symptoms. Oral antihistamines like Claritin, Zyrtec and Allegra, for example, can manage symptoms like a runny or stuffy nose and sneezing, Dr. Yu said.

Saline rinses can also help unclog your sinuses, Dr. Agarwal said, whether you’re suffering from a cold or allergies.

And if you think what you have is indeed a cold, Dr. Yu recommended taking a day off or staying at home to avoid getting others sick as well.