Allergy or a Cold? 5 Ways to Tell the Difference

Your nose is stuffed up. Your throat hurts. You’re sneezing. Is it a cold or an allergic reaction? Sometimes, it’s hard to tell.

The symptoms can be very similar,” says Dr. Meredith Moore, a Charleston Allergy & Asthma physician who is board certified in allergy, asthma and immunology in both pediatrics and adults.

If you aren’t certain which one is ailing you, ask yourself these questions:

1. Do you feel itchy?

Usually what we see with allergies is a lot of itching — itchy eyes, itchy throat, even an itchy nose,” say Dr. Moore. “That’s not going to be a problem with a cold.”

Itching often results from the presence of histamine, a chemical in the body that responds to injury, inflammation and allergens. In the case of allergens, the body’s defense system is overreacting to a perceived threat.

Feeling itchy might mean that you have an allergy.

2. Do you have a fever?

Fevers don’t generally arise from allergies, but it’s common to get a low-grade fever with a cold. Any temperature under 100.4 degrees Fahrenheit is normal, although schools tend to be more conservative and may set the threshold at 100 degrees.

If you have a fever, that might indicate a cold.

3. When are you sick, and for how long?

It’s not uncommon to catch colds over and over again, so being sick often isn’t necessarily a way to distinguish. The frequency of colds depends a lot on your age.

Children catch colds a lot more, especially when they’re in close proximity touching all the same things as other children,” says Dr. Moore. “You see a lot of clusters. It just takes one sick person to infect one person with a cold, and then another and another.”

But even people who get back-to-back colds will notice a difference from allergies in the timing and duration of their illness. Colds tend to occur more often in the fall and winter, when school is in session and relatives are gathering in large numbers for holiday celebrations. It takes about five to 10 days to recover from a cold, and there should be a break of wellness before the next one comes on.

If you’re sick for more than 14 days in a row, it’s likely an allergy. Allergies to dust mites and animals, for example, can cause symptoms year-round, but symptoms from pollen are more common during spring and fall, when airborne pollen is peaking.

Check weather reports to see if your symptoms coincide with periods when pollen counts are high, says Dr. Moore. There is also accurate, real-time pollen data on the Charleston Allergy & Asthma website.

Feeling sick more than two weeks in a row might indicate an allergy.

4. How tired are you?

Fatigue is a feature of both allergies and colds, but it’s more severe if it’s a viral infection or a cold,” explains Dr. Moore.

An allergic reaction is the body’s immune system fighting what it thinks is a toxic invader. It directs energy into attacking this invader, leaving less energy for normal daily activities.

If you’re extremely tired, that could mean an allergy.

5. What medicine are you taking, and is it working?

Over-the-counter antihistamines are not effective against colds, says Dr. Moore. Cold symptoms are not caused by the presence of histamines, so blocking them won’t do any good.

If antihistamines aren’t working, that may indicate a cold.

If you suspect you have allergies, visit your primary care doctor or a board-certified allergist right away to get tested. Charleston Allergy & Asthma has six doctors on staff who are all board-certified allergists and immunologists.

Request a consultation online at