What is an allergic reaction?

Allergic reactions happen when triggers, or allergens, make your immune system overreact and release histamines. Allergies can happen anywhere, anytime. Your friend might bring dander from their dog into your house on their sweater, or you might suddenly start to sneeze while on vacation, at work or school, or in your own back yard.

Who gets unexpected allergic reactions*?

In a given year, 47% of Canadians will suffer from an unexpected allergic reaction*. Even people who think they know their allergies or people who don’t have everyday allergies can have an unexpected allergic reaction.

How do I know it’s allergies and not a cold or flu?

Some symptoms, like a runny nose, could be either a cold or allergies, but others offer better clues. Itchy nose or eyes usually mean allergies. Also, if your symptoms show up when you’re around a certain substance or place, suspect allergies. On the other hand, fever, aches and pains are typically associated with a cold or flu (see chart below for more information).

Symptom comparison chart

Use this chart to help decide if you have allergies, a cold, or the flu. (Not intended as medical advice. See your doctor if you are concerned.)

Symptom

Allergies

Cold

Flu

Stuffy nose
Sometimes
Sneezing
no
no
no
Runny nose
no
no
no
Itchy eyes or nose
no
   
Cough
Sometimes
no
no
Aches & pains  
Sometimes
no
Fever  
Rarely
Sinus Congestion
no
no
no
Sore Throat Pain
rarely
no
no


*Seek medical attention immediately if you are experiencing a life-threatening anaphylactic reaction, as BENADRYL® is not indicated for such use.

What Is an Allergic Reaction?