The Difference Between an Allergy and the Common Cold

You wake up in the morning sneezing, and your nose is running. Your eyes feel irritated and watery. You know you feel awful, but you may be wondering, "Is this an allergy or a common cold?" The symptoms of colds and allergies are often similar, and sometimes telling them apart can be confusing. Understanding the cause of your symptoms helps determine what your ailment is.

Allergy Basics

Allergies occur when a person is exposed to a harmless substance and the body mistakes it for a dangerous foreign invader. An immune response begins to fight off the perceived invader, producing chemicals like histamine and causing allergy symptoms. Allergies can be seasonal or year round, and can develop at any age. Pollens and mold spores are two of the most common triggers, although many common substances can trigger allergic reactions. Allergy symptoms may include:

• coughing
• headache
• hives
• itchy, bloodshot or dry eyes
• itchy throat
• runny nose (clear fluid)
• sneezing
• stuffy nose.

Allergy symptoms persist until you are no longer being exposed to the allergen.

Understanding Colds

The common cold is caused by viruses including:

• coronavirus
• coxsackievirus
• rhinovirus.

Colds are spread either by touch or through the air. If you touch a cold virus on a person or object, and then touch your eyes, mouth, nose or an open wound, you can catch the infection. You can also catch a cold by inhaling virus droplets when an infected person coughs or sneezes. Common cold symptoms include:

• body aches
• cough
• occasional mild fever
• runny or stuffy nose
• sore throat.

Symptoms of the common cold usually last from three to 14 days.

Separating Allergies and Colds

The best way to tell an allergy from a cold is to take a closer look at the symptoms. Some specific symptoms to examine if you are suffering from allergies or a common cold include:

• Coughing: Coughing from allergies lasts a lot longer than coughing due to colds.
• Fever: Fever is very rare in allergies. If your temperature is high, you are more likely to be suffering from a cold.
• Itchy, Red or Watery Eyes: Irritated eye symptoms are more likely to come from allergies than colds.
• Nasal Discharge: Allergies and colds will both make your nose run. With allergies, however, nasal discharge is usually clear. If your nasal discharge is green, white or yellow, you probably have a cold.
• "Sick" Appearance: Allergies may make you feel awful, but don't usually make you look unwell. If you look sick, suspect a cold.
• Sneezing: How often are you sneezing? Colds usually make you sneeze occasionally, while allergies bring on bouts of repeated, prolonged sneezing.
• Sore Throat: Allergies often cause an uncomfortable, scratchy throat, but seldom actual throat pain. If your throat is painfully sore, it is more likely to be due to a cold.
• Swollen Lymph Glands: If the glands in your neck are swollen, a cold is more likely the source than allergies.
• Symptom Duration: Cold symptoms disappear within a few weeks, while allergy symptoms can last many weeks or months.

History and environment also provide clues. If many people around you are catching colds, odds are you have picked up a virus. If pollen or mold counts are high, or you have been exposed to other common allergens, you may be experiencing an allergy. If you have a family history of year-round or seasonal allergies, your odds are increased for developing allergies yourself.

Finding Allergy Relief

If you find you are suffering from allergies, relief is in sight. Avoiding exposure to your allergy triggers is a great way to start. Your doctor can perform allergy tests to identify your exact allergy triggers. If you are allergic to pollen, you may find relief by simply closing doors and windows, and running your air conditioner. Both over-the-counter and prescription medications are available if avoiding triggers is not enough. Some ways allergies are treated include:

• antihistamines
• cromolyn sodium
• decongestants
• immunotherapy (allergy shots)
• leukotriene modifiers
• nasal atropine
• nasal corticosteroids
• oral corticosteroids
• saline nasal rinse.

Resources

Cates, L., M.D., F.A.A.P. (2004). Allergy or cold: How to tell. Retrieved March 23, 2009, from the Dr. Spock Web site: http://www.drspock.com/article/0,1510,5457,00.html.

Duda, K., R.N. (2008). Allergies or a cold? Retrieved March 23, 2009, from the About.com Web site: http://coldflu.about.com/od/othercommonillnesses/a/allergiesvscold.htm.

Mayo Foundation for Medical Education and Research. (2007). Cold or allergy: Which is it? Retrieved March 23, 2009, from the MayoClinic.com Web site: http://www.mayoclinic.com/health/common-cold/AN01229.

Mayo Foundation for Medical Education and Research. (2008). Hay fever. Treatment and drugs. Retrieved March 23, 2009, from the MayoClinic.com Web site: http://www.mayoclinic.com/health/hay-fever/DS00174/DSECTION=treatments-and-drugs.