Allergy or Cold?

By: Marion Richman, MD
As many as 40 million Americans suffer from allergies, and many more suffer from the common cold. Allergies and colds share many of the same symptoms, and effective treatment depends on knowing which one you have. But how can you be sure which one you are suffering from? As a family doctor at New York Presbyterian-Columbia, Dr. Marion Richman has seen her share of both maladies. Below, she answers some fundamental questions about making the distinction between allergy and the common cold.
Do you find that patients often confuse colds and allergy?
Definitely. There are just so many overlapping symptoms between the two that it's very easy to confuse them. Doctors confuse them as well.

So what is the difference between what causes a cold and an allergy?
An allergy is an immune response to a substance in the environment that's normally harmless, so it's an inappropriate immune response. A cold is an infection which is contagious. Ninety-nine percent of the time it is caused by a virus, and very rarely by a bacteria.

What are the signs and symptoms of each one?
The signs that are common to the two are runny nose and nasal congestion. More particular to allergies are the itchy, watery eyes, the clear, runny nose, and the itchy throat. With colds you are more likely to have a fever, and you may have some sinus pain, and the mucus discharge may be a different color, like green or yellow.


How can a person tell the difference?
It's difficult. But if you're getting a cold at the same time every year, or after you visit your cousin who has a cat, you might suspect it's an allergy. There are also some other telltale signs of having an allergy, like if the person also has eczema, itchy skin, asthma, or a history of allergies in their family. A cold usually follows a time course of about seven to ten days, usually with a predictable series of symptoms. But it is possible that they have identical symptoms.

How does a doctor tell them apart?
Using the same detective work as I mentioned, but sometimes it's trial and error. If the person's coming back to you again and again and the cold remedies that you're recommending aren't working, you can begin to suspect it's an allergy.

What are the treatment options for a cold?
We don't have a cure for the cold, so the treatment options are limited to treating the symptoms. For the congestion there are decongestants. For runny nose there are antihistamines. Cough suppressants can help with a cough.

What are the treatment options for allergies?
Before any kind of medical treatment, it's best to try to modify your lifestyle, to avoid what is causing your allergies. For example, if you're allergic to cats, try to avoid them.
Treatment options for allergies are a little broader. You can use the over-the-counter cold remedies. But, the non-sedating antihistamines are a mainstay of allergy treatment. Steroids, which help reduce inflammation, are also used. They can be sprayed into the nose, and we also have oral steroids for very severe allergy sufferers that can be taken for short courses. We also have allergy shots, or immunotherapy, which are used to inject small doses of substances that you are allergic to. The idea is to try to increase the person's tolerance to that substance. Allergy shots are usually reserved for people who have severe allergies.

At what point should a person with congestion, runny nose and sneezing see a doctor?
If it's a cold, it's usually going to follow a time course of about seven to ten days. If you've had a cold for a month, you should go see a doctor. If you have a temperature of over 101 for three days or more, or if you develop ear pain, throat pain, sinus pain, or pain in your teeth, you could be getting an infection, and should see a doctor. If there's any trouble breathing, you should go to the emergency room immediately.

Children also suffer from allergies and colds. What are some clues that a child may have allergies? Allergies are kind of rare in kids under three. But in the over-three crowd, if they're getting recurrent ear infections or hearing problems, and these problems are leading to trouble in school, you might want to see the child's doctor, and inquire if the problem might be related to an allergy.


Children often have similar allergy symptoms to adults, like a clear, runny nose. Often you see them rubbing their nose, and some kids even have a little crease across the bridge of their nose from the constant rubbing and pushing.

What are some signs and symptoms that require a doctor's visit?
Fever is definitely a warning sign. Allergies don't usually cause fever, so if they do have a fever or if they're complaining of any kind of pain in their ears or throat, and certainly if they're having any trouble breathing, then they should see a doctor. If they're not taking in food as much as they usually do, not drinking or not making wet diapers, those are definite reasons to come to the doctor immediately.

What are some of the treatments available for children with cold or allergy?
I feel that with young children, over-the-counter medicines for colds, and even the prescription ones, are not that effective, and using these medications are not worth the risk of side effects. Toughing it out is a better approach to a child's cold.

In terms of allergies, there are some non-sedating antihistamines that are approved for children as young as two years of age, and they come in syrup form or they come in dissolvable tablets that go under the tongue. For the kids that truly have allergies, those treatments are out there for them.

I'm just trying to find information anyone might have about an illness that has "steps"--one or two symptoms at a time, changing as it progresses, or whether this is a quirky combination of an illness and my allergies both ganging up on me. I'm taking my usual allergy medicines, and haven't changed my lifestyle too much since I was last coping with my allergies, and I've been taking varying medicines to treat my individual symptoms, (Cough medicine and decongestants) with little effect. I've been trying to find a local doctor, but no luck so far, and I just wanted to know if I should just forget about trying to treat my symptoms since they aren't budging one way or the other. Any suggestions?

Can you please tell me what your symptoms are and how long you have been experiencing them?