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Ocular Allergy

What Are Eye Allergies?
        Eye allergies, called allergic conjunctivitis, are a common condition that occurs when the eyes react to something that irritates them (called an allergen). The eyes produce a substance called histamine to fight off the allergen. As a result, the eyelids and conjunctiva — the thin, filmy membrane that covers the inside of your eyelids and the white part of your eye (sclera) — become red, swollen and itchy, with tearing and burning. Unlike bacterial or viral conjunctivitis, allergic conjunctivitis is not spread from person to person.People who suffer from eye allergies usually (though not always) have nasal allergies as well, with an itchy, stuffy nose and sneezing. It is usually a temporary (acute) condition associated with seasonal allergies. However, in other cases, eye allergies can develop from exposure to other environmental triggers, such as pet dander, dust, pollen, smoke, perfumes, or even foods. If the exposure is ongoing, the allergies can be more severe, with significant burning and itching and even sensitivity to light.
 
        Symptoms : The most common eye allergy symptoms include
        Red, swollen or itchy eyes
        Burning or tearing of the eyes
        Sensitivity to light
        If accompanied by nasal allergies, you may also experience a stuffy, itchy nose and sneezing, as well as a headache, an itchy or sore throat or coughing.
 
        What Causes Eye Allergies?
        An allergy is when the body's immune system reacts to something (called an allergen) that is normally harmless. When an allergen comes in contact with your eye, certain cells within the eye (called mast cells) release histamine and other substances to fight off the allergen. This reaction causes your eyes to become red, itchy and watery.
       Many eye allergies are caused by the body’s response to allergens in the air — both indoors and out — such as dust, pet dander, mold, or smoke. Some of the most common airborne allergens include pollen from grass, trees and ragweed, contributing to seasonal allergies.
       Allergic reactions to perfume, cosmetics or drugs can also cause the eyes to have an allergic response. Some people may be allergic to the preservative chemicals in lubricating eye drops. They should use preservative-free drops instead.
      Sometimes, the eyes can react to other allergens that don't necessarily come in direct contact with the eye, such as specific types of food or insect bites or stings.
      Some people can inherit eye allergies from their parents. You're more likely to have allergies if both of your parents have them than if only one does.
 
        Eye allergy diagnosis
        To provide proper treatment, your ophthalmologist will check to see whether your symptoms are related to an eye infection or allergic conjunctivitis. He or she can usually diagnose allergic conjunctivitis easily by examining your eyes and discussing your medical history — including your history and your family's history of allergies.
        Your ophthalmologist will examine your eyes with a slit lamp microscope to check for signs of eye allergies, such as swollen blood vessels on the surface of the eye. If your allergies are severe, or if it is not completely clear that you have allergic conjunctivitis, your ophthalmologist may choose to test for specific type of white blood cells (called eosinophils) that show up in areas of the eye where there is an allergic reaction to something. This test is done by gently scraping a tiny area of the conjunctiva and testing this tissue for eosinophils.
 
        Eye allergy treatment
        The key to treating eye allergies is to avoid or limit contact with the substance causing the problem. But you have to know what to avoid. If necessary, an allergist can perform a skin or blood test to help identify the specific allergen(s).
        Avoiding allergens
        If pollen is an allergen for you, avoid going outdoors as much as possible when pollen counts are highest (generally mid-morning and early evening) and when wind blows pollens around. When you are outdoors, sunglasses or eyeglasses can help to prevent pollen from getting into your eyes.
       To help minimize your exposure to pollen and other irritants while you are inside, keep your windows closed and use air conditioning — both in your car and home. Don't use window fans, as they draw the pollen and other allergens inside. Keep your air conditioning units clean so they won't cycle allergens inside.
       If mold is an allergy trigger for you, recognize that high humidity can cause molds to grow. Aim to keep the humidity level in your home around 30 to 50 percent. Clean high-humidity areas like basements, bathrooms and kitchens frequently, and consider using a dehumidifier in particularly humid or moist places (such as a basement).
       If dust at home brings on your allergic conjunctivitis, try to cut down your exposure to dust mites, particularly in your bedroom. Use special allergen-reducing covers for your bedding — particularly your pillows — to keep dust mites away from your skin. Wash your bedding frequently, using hot water that is at least 130 degrees F. When cleaning your floors, instead of using a dry dust mop or broom, use a damp mop or rag to trap the allergens.
       If pets are a source of allergies for you, try to keep animals outside of the house as much as possible. It is particularly important not to allow a pet into your bedroom so that you can sleep in an allergen-free room. Consider hardwood or tile floors instead of carpeting, which traps the pet dander. Always wash your hands after touching a pet and wash clothing that has been exposed to pets. Finally, always avoid rubbing your eyes, which only irritates them more. Treating eye allergies with eye drops and medicine

         Artificial tears
         Artificial tear drops can help relieve eye allergies temporarily by washing allergens from the eye. They also relieve dry, irritated eyes by adding moisture. These drops, available without a prescription, can be used as often as you need them.

        Decongestants (with or without antihistamines)
        Decongestants reduce redness in the eyes from allergies. They are available as over-the-counter eye drops. They may be sold simply as a decongestant or as a decongestant with an antihistamine, which relieves eye itchiness. These types of eye drops should not be used for more than two to three days, as longer-term use actually increases your irritating symptoms.

         Oral antihistamines
         Oral antihistamines may be somewhat helpful in relieving itchy eyes; however, they can make eyes dry and even worsen eye allergy symptoms.

         Antihistamine/mast-cell stabilizers
         Eye drops with both an antihistamine to relieve itchiness and a mast-cell stabilizer help prevent eye allergies. Depending on your particular eye drop of choice, they are used once or twice a day to relieve itching, redness, tearing and burning.

       Corticosteroids
       Steroid eye drops can help treat chronic and severe eye allergy symptoms such as itching, redness and swelling. Immunotherapy shots. If symptoms are not controlled by allergen avoidance, eye drops or medicine, immunotherapy (allergy shots) may be an option for relieving eye allergies. With immunotherapy, shots containing tiny amounts of the allergen are given, with the dose gradually increasing over time, to help your body become immune to the allergens. Your doctor can help determine which treatments are best for you.


by www.aao.org