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An allergy is a sensitivity to certain substances (allergens) that, under
normal conditions, are considered innocuous to others. Allergens are specific, allergy-producing,
protein substances that catalyze a series of chemical reactions within the body's
immune system. These reactions result in the release of organic compounds, known
as histamine, into the blood stream that cause the signs and symptoms related to
the allergic condition.
Generally, allergens may be categorized into four basic types:
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Airborne - Because they often come into contact with the eyes
and nose, they represent the main source for ocular allergies and are also responsible
for sneezing, asthma, etc. Examples include pollen, mold, dust, and animal dander.
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Contactants - for example, poison ivy, dyes, make-up, and certain
chemicals. This type of allergen will often cause skin irritations or rashes.
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Food - may cause rashes, hives, or a respiratory reaction. Examples
may include fish and chocolate.
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Drug - (e.g. sulfa drugs) - often responsible for violent respiratory
or other reactions.
Ocular allergies tend to present themselves in and around the area known
as the conjunctiva. The conjunctiva is a transparent mucosal membrane that lines
the sclera and underneath the eyelid. A condition known as conjunctivitis (commonly
referred to as "pink eye") occurs when the conjunctiva becomes infected via allergy.
Ocular allergies have several forms and may be either seasonal or perennial
in nature. One of the most common types of ocular allergy is Allergic Conjunctivitis.
It is most common in the spring and fall (hay fever season). This type is caused
by airborne allergens and may result in itching, excessive tearing, and swollen
eyelids. More severe cases may also present a burning sensation and a water-like
discharge.
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Medicated eye drops may be prescribed by an optometrist to provide immediate
relief from the symptoms caused by airborne allergens (antihistamines), to alleviate
swelling and redness (decongestants), and perhaps to provide long-lasting relief
from symptoms (mast cell stabilizers). Over-the-counter drops are available as well,
but BE CAREFUL - contact an eyecare professional BEFORE using any over-the-counter
drops, especially when wearing contact lenses. Certain types of eye drops may discolor
or damage your contact lenses!
Immunotherapy is another option for relief from allergies. This involves
visiting an allergy specialist to undergo a series of injections that contain small
amounts of allergens. This is done in order to gradually build up immunity to the
given allergens.
Note: Signs and symptoms of allergic infections closely mirror
those of bacterial and viral infections. It is important to make an appointment
with your eyecare practitioner in order to determine the proper course of treatment.
Self-diagnosis and treatment may only worsen the condition.
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