Eye Allergy (cont.)
Jay Robert Woody, MD
Dr. Jay Woody is a diplomat of the American Board of Emergency Medicine, a Fellow of the American College of Emergency Medicine and is an Attending Physician at Parkland Health and Hospital System, Children's Medical Center of Dallas as well as several other north Texas facilities. He is a well-known and widely published authority in the field of emergency medicine and the former regional medical director of a freestanding emergency medicine practice.
Melissa Conrad Stöppler, MD
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
In this Article
- Eye allergy facts
- Eye allergy introduction
- What causes eye allergies?
- What is the basic anatomy of the outer eye?
- Why are the eyes an easy target for allergies?
- What are symptoms and signs of eye allergies?
- What are allergic eye conditions?
- What are eyelid allergies (also called contact eye allergies)?
- What conditions can be confused with eye allergies?
- What is the treatment for eye allergies?
- What is the prognosis of eye allergies?
- Can eye allergies be prevented?
- Find a local Asthma & Allergy Specialist in your town
What is the basic anatomy of the outer eye?
Eye allergies mainly involve the conjunctiva, 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.
Approximately 54 million people, about 20% of the U.S. population, have 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 the allergy 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.
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