Is It a Cold Or Allergies?
Can't tell whether your scratchy throat is a sign of a cold or allergies? Here's how to tell the difference between allergies vs. cold, according to experts.
Congestion, sniffling, and sneezing are all waving red flags that you're coming down with something. But is it a cold or allergies?
Since cold and allergy symptoms tend to overlap, it's easy to confuse the two. Even experts admit it can be challenging to decipher one from the other—not just because of their similarities, but also because they're sometimes related to one another. "If you have persistent allergy symptoms, the inflammation associated with allergies can make you more susceptible to 'catching a cold,'" says Lakiea Wright, M.D., a board-certified allergist and staff physician at Brigham and Women's Hospital.
Still, colds and allergies aren't one and the same. Here's how to tell the difference between the two, plus differences in allergies vs. cold treatment so you can get the relief you need.
Cold vs. Allergy Symptoms
There are a few key differences to note when looking at allergies vs. cold symptoms—the most significant being what actually triggers them.
While the common cold is typically caused by a contagious viral infection, you can't "catch" allergies from another person, explains Dr. Wright. Allergy symptoms and allergic reactions happen when the immune system overreacts to an environmental substance (including things like pollen, pet dander, mold, food, medication, plants, chemicals, insect stings, etc.), she says. (Related: Do You Really Have a Food Allergy?)
But what if you haven't been diagnosed with seasonal allergies? How can you tell the difference between cold vs. allergy symptoms when your nose is running like a faucet, you're congested AF, and you can't stop sneezing? Below, experts break down allergies vs. cold by symptoms.
If you have a fever, it's a cold. Because allergies are a response to specific environmental substances, people with allergies rarely have a fever, says Soma Mandal, M.D., board-certified internist at Summit Medical Group in Berkeley Heights, New Jersey. Rather, low-grade fevers tend to be a sign of viral infection (aka a cold), she explains. So if you're feeling a little warm—not to mention experiencing general aches and chills—these signs point to the common cold, says Dr. Mandal. (Though it could also be the flu—here's how to tell the difference between cold vs. flu.)
If you're itchy, it's allergies. Are you constantly rubbing your nose, eyes, or skin? Do you feel an itch you can't quite scratch at the back of your throat? These are all allergic rhinitis (aka hay fever or allergy) symptoms that can be triggered when your immune system overreacts to allergens in the air, explains Purvi Parikh, M.D., an allergist and immunologist with the Allergy and Asthma Network.
If you break out in hives or a rash, it's allergies. Changes in the skin are usually tell-tale signs of an allergic reaction, notes Dr. Parikh. Painful, itchy rash, blisters, and other skin conditions like eczema, hives, and contact dermatitis are some of the most common skin ailments related to allergies, she explains. These skin allergy symptoms can happen after eating certain foods (nuts, eggs, dairy, shellfish, etc.), taking medication (such as certain antibiotics), spending time outdoors in the presence of an allergen (like pollen), insect bites and stings, and/or direct contact with certain plants and chemicals, according to the American College of Allergy, Asthma, and Immunology (ACAAI). (Note: Viral rashes, caused by viral infections like colds, can also be a thing. But they don't typically cause itching or pain and usually go away after a few days, according to the nonprofit health system Fairview Health Services.)
If your symptoms don't last longer than a week, it's a cold. Duration and timing of symptoms can be big clues in helping you distinguish between cold vs. allergy symptoms. Allergies tend to appear during certain times of the year (spring allergies are probably the most talked-about, though technically, allergy season can last all year), or when you're in an environment that exposes you to certain allergens (think: pet dander, mold, etc.), says Tania Elliott, M.D., a board-certified internal medicine physician and immunologist. "[Allergy] symptoms also tend to be more persistent [than cold symptoms]," she adds, explaining that allergies can last a few weeks to a few months. Colds, on the other hand, have a more sudden onset and usually last between three and 10 days maximum (any longer could mean it's a bacterial, rather than viral infection, if not allergies), notes Dr. Parikh. (Related: The Most Common Allergy Symptoms to Look Out for, Broken Down By Season)
If you're coughing up mucus, it could be a cold or allergies—it depends. Coughing—and the (not so) lovely mucus that comes with it—can, unfortunately, be a sign of either a cold or allergies. The good news: There are some specifics you can pay attention to when distinguishing between allergies vs. cold symptoms like coughing.
For instance, a cold cough doesn't usually feel the same as an allergy cough, says Dr. Elliott. The difference: consistency of the mucus. Mucus caused by a cold is usually thick, whereas mucus associated with allergies tends to be more watery, resulting in a dry cough, she explains. So if your cough is dry, as if you were trying to scratch a tickle at the back of your throat, it's probably an allergy cough. If you're stuffy, have a postnasal drip, and feel like you're hacking up a lung every five seconds, that sounds more like a cold cough, says Dr. Elliott.
That said, sometimes there's overlap between mucus-related cold vs. allergy symptoms. Case in point: Many people assume that greenish or yellowish mucus is a sign of a viral (read: cold) or bacterial infection, while clear mucus is exclusive to allergies. In reality, though, both cold and allergy symptoms can include clear mucus or greenish mucus, according to the ACAAI.
Allergies vs. Cold Diagnosis and Treatment
Clearly, playing the "cold or allergies quiz" with yourself can get pretty confusing. So if you're really struggling to tell whether your symptoms are a result of a cold or allergies, it's best to touch base with your doc directly. (Related: How to Stay Healthy—Period, According to Doctors Who Live By These Rules)
First, they'll likely ask for the specifics of your symptoms: what are they, how long have you been experiencing them, and their severity, says Dr. Mandal.
Once your doc has a thorough history of your symptoms, they'll move on to a physical exam, explains Dr. Mandal. "If your doctor thinks that you have an allergy, they will examine your ears, eyes, nose, throat, chest, and skin carefully," she explains. Depending on the severity of your symptoms, they might also issue various allergy tests (i.e. skin or blood tests) to figure out what, specifically, is causing the allergic reaction, she adds.
If your doctor thinks you have a cold, on the other hand, they'll check for fever and look for signs of other conditions like strep throat, sinus infection, flu, or pneumonia, explains Dr. Mandal.
As for the treatment of allergies vs. cold symptoms, the goal is pretty similar in both cases: relieve the symptoms that are making you most miserable, says Dr. Mandal. That said, the actual medications for cold vs. allergy symptoms treatment are different.
For general allergy symptoms, experts often recommend OTC meds like Claritin, Zyrtec, Allegra, and Benadryl, notes Dr. Mandal. But you'll want to use nasal decongestants and sprays (such as Flonase) to treat allergy symptoms like congestion, sneezing, and runny nose, she says. Allergy-induced hives or rash can often be treated with topical or oral steroids, she adds.
When treating a cold (aka a viral infection), your best line of defense is getting plenty of rest and drinking lots of fluids, explains Dr. Mandal. If you have a sore throat or cough, OTC throat sprays and lozenges can help ease the sting, while OTC cold relief meds like Dayquil can reduce general aches, pains, and fever. (Here's a full breakdown of the best cold medicines for every symptom.)