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Allergies or a cold? How to tell the difference


reviewed 10/25/2018

Is it allergies or a cold?

If you're not sure whether symptoms such as a runny nose, sneezing or cough might be due to an allergy or a cold, answering the following questions may be helpful.

Note: This assessment is not intended to be a substitute for a visit with your healthcare provider.

Have you had symptoms longer than one week?

If you answered "yes." Length of symptoms is the main difference between a cold and an allergy. A cold will last until it runs its course. That's usually about one week. But allergies occur whenever you're exposed to something you're sensitive to (an allergen). Allergies may, therefore, last much longer than a week.

If you answered "no." Length of symptoms is the main difference between a cold and an allergy. A cold will last until it runs its course. That's usually about one week. But allergies occur whenever you're exposed to something you're sensitive to (an allergen). Allergies may, therefore, last much longer than a week.

Did your symptoms begin rather suddenly or build up over a few days?

If you answered "began rather suddenly." When symptoms are due to an allergy, they may begin almost immediately after you're exposed to something that you're allergic to. Allergy symptoms occur when the body sees a normally harmless substance (such as pollen or dust) as a threat and attacks it.

If you answered "built up over a few days." Symptoms of a cold usually don’t develop until a few days after you're exposed to germs. You catch a cold when you breathe in germs or come in direct contact with someone who is infected. You may also get a cold by using something, such as a cup or towel, that someone who is sick has used. While colds are contagious, allergies are not.

Do you have a fever or achiness?

If you answered "yes." Although there may be other causes, most fevers are due to infection. Colds are caused by infections, but allergies aren't. So symptoms that include a fever would generally rule out an allergy. An achy body also tends to suggest that you have a cold, not an allergy. However, fever and achiness are more typical of the flu than a cold.

If you answered "no." Fever and achiness are almost always caused by an infection, not allergies.

If you have nasal discharge, is it thin, watery and clear or thick and colored?

If you answered "thin, watery and clear." Nasal discharge due to allergies is usually thin, watery and clear. A cold may also produce clear nasal discharge at first, but it may turn colored and thick.

If you answered "thick and colored." Discharge that is thick and colored is likely due to a cold or some type of respiratory infection. Initially, the discharge may have been clear, however.

Do you have itching of the eyes, nose or throat?

If you answered "yes." Itching tends to be a symptom of allergies. It is rare with a cold.

If you answered "no." Itching rarely occurs with a cold but may be present with allergies.

Do you sneeze frequently?

If you answered "yes." Sneezing may occur with both allergies and colds, but if you have prolonged attacks of sneezing, it is more likely that they are due to an allergy than a cold.

If you answered "no." Occasional sneezing may be due to a cold, but if you have prolonged bouts of sneezing, it may be a symptom of an allergy.

Though you may now have a better idea of whether you have a cold or an allergy, it's important to realize that this assessment should not take the place of a visit with your healthcare provider. He or she can offer more information about how to tell if you have a cold or an allergy and the best way to treat the problem.

Learn more about allergies.

Learn more about the common cold.

Sources: American Academy of Allergy, Asthma & Immunology; American Academy of Family Physicians; American Academy of Pediatrics; American College of Allergy, Asthma & Immunology; National Institutes of Health

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