Suffering from seasonal allergies?

ALLERGIES AND YOUR EYES

WHAT IS AN ALLERGY?

Allergic reactions occur when the immune system overreacts to an ordinarily harmless or foreign substance that it perceives to be an invader, known as an allergen.  The immune system mounts a defensive attack against the allergen with various antibodies, which results in the release of high quantities of chemicals (including histamine).  The release of these chemicals causes an inflammatory response that leads to the classic ocular symptoms of itching, tearing, redness, swelling, irritation, stringy discharge and soreness. 

Seven percent of the Canadian population is estimated to suffer from eye allergies, of which there are two common types.  Seasonal allergic conjunctivitis is caused by specific allergens such as ragweed, grass or tree pollens that occur seasonally at approximately the same time each year.  In British Columbia, tree pollen occurs in the months of February through May; grass pollen in June and July; and ragweed in August and September.  July and August tend to be the worst months for allergy sufferers because the presence of grass and ragweed overlaps.  Perennial (year-round) allergic conjunctivitis is often caused by animal hair, dust, mold, wool, feathers and other allergens that tend to be present throughout the year.

HOW ARE EYE ALLERGIES TREATED?

Unfortunately, there is no known cure for an allergy.  Treatment consists of avoiding allergy triggers and using medications to provide prevention or relief of symptoms.  Avoiding an allergen can be quite difficult, but some tips on how to do so are:

·   Watch the pollen forecasts. When pollen counts are high, try to stay indoors particularly when pollen release is at its peak (usually early morning hours) and on dry, windy days.

·   Keep your household windows closed so pollens are kept outside, and when driving in your car, use your air conditioning with your windows rolled up.

·   Avoid direct exposure to grasses.  Keep your lawn short during the summer.

·   Molds thrive in dampness, so reduce humidity in your home with an air conditioner or dehumidifier.  Change or clean the filtration unit often to prevent mold build-up.

·   Keep dust to a minimum; keep carpets, rugs and blankets as clean as possible, and clean under beds and couches where dust builds up.

When exposure to an allergen cannot be avoided, several treatment options are available.  The use of artificial tears to help wash away and reduce contact with an allergen, and cool compresses to constrict blood vessels can often be helpful.  The two main types of ocular medications for allergies are anti-histamines and mast-cell stabilizers.  Different formulations are available both over-the-counter and by prescription, including various combination medications. 

Anti-histamine eye drops provide immediate but temporary relief of symptoms related to an allergy response.  Over-the-counter preparations are typically combined with a decongestant (vasoconstrictor) ingredient.  These OTC medications should not be used for more than three to five consecutive days to prevent rebound redness problems, and thus are best for occasional use only.  Mast-cell stabilizers help to prevent an allergic response from occurring by blocking the release of chemicals that trigger allergy symptoms.  In order to be effective, the medication must be taken on a continual basis and can take up to two to three weeks to be maximally effective.  Thus, this type of anti-allergy medication provides a good choice for sustained, long-term relief.  These drops can be started just prior to the usual allergy season to allow time for the medication to achieve full effectiveness. 

It is not recommended that you diagnose and treat your allergy symptoms on your own.  Several different eye conditions can mimic the symptoms of allergies, and anti-allergy medications are not without possible side effects or reactions with other systemic medications.  Your eye care professional is specially trained in this area and is best qualified to recommend the right treatment for you.