Understanding the Eye Allergies (1 of 2)

Eye allergy facts:

• Most allergic eye conditions are more irritating than dangerous.
• Allergic or vernal keratoconjunctivitismay result in scarring of the corneaand visual problems.
• Itchy eyes are probably allergic eyes.
• Topical antihistamine/decongestantpreparations are effective and safe for mildly itchy, red eyes.
• Patanol, a topical mast-cell stabilizer, is a safe, highly effective, long-acting treatment.
• Topical steroids should be used with caution and under the supervision of an ophthalmologist.
• If in doubt about an eye condition, seek medical advice sooner rather than later.

Eye allergy introduction

The eyes are the windows to the soul because they reflect our state of mind. This certainly can't be true if our eyes are red, swollen, watery, and itchy from anallergic reaction. Severe allergic eye symptoms can be very distressing and are a common reason for visits to the allergist, ophthalmologist, and even the emergency room. Occasionally, severe eye allergiescause serious damage that can threaten eyesight.

What causes eye allergies?

• 
  

Eye allergies usually are associated with other allergic conditions, particularly hay fever (allergic rhinitis) and atopiceczema (dermatitis). The causes of eyeallergies are similar to those of allergicasthma and hay fever. Medications andcosmetics can play a significant role in causing eye allergies. Reactions to eye irritants and other eye conditions (for example, infections such as pink eye) are often confused with eye allergy. Any kind of irritant, whether environmental, infectious, or manmade, can cause symptoms consistent with eye allergies.

What is the basic anatomy of the outer eye?

Eye allergies mainly involve theconjunctiva, which is the tissue lining (mucus membrane) that covers the white surface of the eyeball and the inner folds of the eyelids. The conjunctiva is a barrier structure that is exposed to the environment and the many different allergens (substances that stimulate an allergic response) that become airborne. It is rich in blood vessels and contains more mast cells (cells that release histamine, a chemical mediator of allergic reactions) than the lungs.

The lacrimal (tear) glands are located in the upper and outer portions of the eye. They are responsible for producing the watery component of tears, which keeps the eye moist and washes away irritants. The tears also contain important components of the immune defense such as immunoglobulins (antibodies), lymphocytes (specialized white blood cells), and enzymes.

The cornea is the transparent sheath in front of the lens of the eye. The cornea has no blood vessels and very little immune activity.

Why are the eyes an easy target for allergies?

When you open your eyes, the conjunctiva becomes directly exposed to the environment without the help of a filtering system such as the cilia, the hairs commonly found in the nose.

Allergy fact

Approximately 54 million people, about 20% of the U.S. population, have symptoms of allergies. Almost half of these people have allergic eye disease.

People who are more susceptible to allergic eye disease are those with a history of allergic rhinitis and atopic dermatitis and those with a strong family and/or personal history of allergy. Symptoms usually appear before the age of 30.

The scenario for developing allergy symptoms is much the same for the eyes as that for the nose. Allergens cause theallergy antibody IgE to coat numerous mast cells in the conjunctiva. Upon reexposure to the allergen, the mast cell is prompted to release histamine and other mediators. The result is itching, burning, and runny eyes that become red and irritated due to inflammation, which results in congestion. The eyelids may swell, even to the point of closing altogether. Sometimes, the conjunctiva swells with fluid and protrudes from the surface of the eye, resembling a "hive" on the eye. These reactions may also induce light sensitivity. Typically, both eyes are affected by an allergic reaction. Occasionally, only one eye is involved, particularly when only one eye is rubbed with an allergen, as this causes mast cells to release more histamine.

What are symptoms and signs of eye allergies?

Typical symptoms associated with eye allergies include inflammation of the conjunctiva that is caused by a reaction to allergens. The inflammation causes enlargement of the blood vessels in the conjunctiva ("congestion"), resulting in a red or bloodshot appearance of the eyes. These symptoms can range from very mild redness to severe swelling associated with discharge.

Continued to ........... Understanding the Eye Allergies (2 of 2)