Allergy 101: Outdoor Versus Indoor Allergies

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After a long, cold winter many Canadians are excited to trade in their winter hat for a ball cap and some sunshine. But while spring signals the start of warmer weather, it also means the start of allergy season. For many pharmacists, allergies are the second most common minor ailment patients ask about, just behind cold sores. In fact, allergies affect an estimated 20-25 per cent of Canadians! i

There are actually two main causes of allergy symptoms: indoor and outdoor triggers. While most people understand seasonal (outdoor) allergies are caused by pollen in the air, there are a number of factors that contribute to indoor allergies, which can affect people year-round. Symptoms can be similar, but it’s important to remember indoor and outdoor allergies are caused by different sources, and therefore should be managed differently. Here are some of the main triggers of indoor allergies that you should be aware of: ii

  • Dust: Dust is made up of any number of things, including particles from plants, skin, soil, insects, food and other fibres. Anyone of these microscopic substances could cause irritation.
  • Dust Mites: Dust mite droppings are the most common trigger of indoor allergy symptoms. Keep in mind that dust mites tend to concentrate in areas rich with human dander such as bedrooms, carpets and bathroom rugs.
  • Mould: Once mould and mildew take hold, they release tiny spores that can trigger indoor allergy symptoms.
  • Pet Dander: Pet dander is caused by a tiny protein in your pets’ saliva. Even homes without pets are susceptible to dander because pet dander is sticky and light, it clings to clothes, shoes and hair, getting tracked inside.

While there is no cure for allergies, the best way to handle them is to identify your triggers so they can be managed. Grooming pets, cleaning and lowering your home’s humidity are all great ways to minimize symptoms of indoor allergies. If they persist, treatment is always an option. Your local pharmacists can evaluate your symptoms and help find the appropriate solution to relieve them.

Pharmacists are trained to assess your health condition and help provide the most appropriate treatment option for you. Your pharmacist may start by recommending over-the-counter medications or products. In all provinces except British Columbia and Ontario, pharmacists can prescribe for minor ailments, so if appropriate, your pharmacist can even write you a prescription for your allergies.

If you’re one of the many Canadians who suffers from allergies and are looking for help, ask your local Shoppers Drug Mart pharmacist or visit



i Keith PK, Desrosiers M, Laister T, et al. The Burden of Allergic Rhinitis (AR) in Canada: Perspectives of Physicians and Patients. Allergy, Asthma & Clin Immunol 2012;8:7. Available:

ii American Academy of Allergy Asthma and Immunology.