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Environmental Allergies

Environmental allergies can cause symptoms that affect your eyes, nose, and lungs.

These allergic conditions are called:

Allergic Conjunctivitis

Allergic Rhinitis

Allergic Asthma

Allergies are common. Up to 40% of children and 30% of adults suffer from environmental allergies.

Click on the pictures above to learn more about the symptoms of these conditions.

What am I allergic to?

Substances that cause allergy are called allergens. Patients with symptoms of rhinitis, conjunctivitis, or asthma can be sensitized to allergens that are around all year, while others will be sensitized to allergens only during certain seasons.

About 20% of patients will have year-round symptoms only. About 40% will have seasonal allergies only, while the remaining 40% will have year round symptoms with worsening during a given season.

Click on the pictures to see the most common sources of year-round and seasonal allergies.

How do I avoid the things I am allergic to?

The first step in treating allergies is reducing the amount of allergen to which you are exposed.

Click on the allergens below to read more about them and the best ways to avoid them.

House Dust Mites

Pet Dander

Pollen & Moulds

How are environmental allergies treated?

Most patients will require medical therapies to treat their environmental allergies. The treatment options depend on your symptoms. Treatments for conjunctivitis and rhinitis are summarized below.

Asthma treatment is discussed separately here.


Non-sedating antihistamines can be purchased over-the-counter from your pharmacy. They can treat many of the symptoms of allergic conjunctivitis and rhinitis.

Of note, however, antihistamines are not effective at treating symptoms of nasal congestion.

Antihistamine Eye Drops

Your family physician or allergy specialist may prescribe an antihistamine eye drop for allergic conjunctivitis. You can use this on a daily basis while you are symptomatic. 

Nasal Steroid Sprays

Nasal steroid sprays are an effective treatment for all symptoms of allergic rhinitis including nasal congestion. They are available both over-the-counter and by prescription.


These are not the same as decongestant sprays, which should not be used as a long term treatment. Ask your physician or pharmacist to help you choose the appropriate treatment.


Immunotherapy (allergy shots or tablets) is a highly effective treatment in patients with environmental allergies.

Your asthma & allergy specialist will assess whether you are a candidate for this therapy.

Allergen immunotherapy works by gradually exposing the patient's immune system to the allergen that is causing symptoms.


It is the only treatment available that actually changes the underlying immune problems that cause allergic inflammation.


Most patients (up to 80%) will have a significant improvement with immunotherapy.

Read more about immunotherapy here.


Illustrations used with permission. Provided courtesy of EBME inc.


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