Nearly 27 million Americans are reported to have some kind of eye allergy. Symptoms of eye allergy, if severe, can be extremely distressing requiring consultations with an allergist or ophthalmologist. If not treated in time, it can even threaten eyesight.
Eye allergy in most cases is linked to other allergic conditions, including hay fever or allergic rhinitis and a topic eczema or dermatitis. Those having personal or family history of allergy are more likely to have eye allergy, its symptoms mostly appearing before the age of 30. Its causes are identical with those of allergic asthma and hay fever. Medications and cosmetics are often major causes of the eye allergy.
To understand the eye allergy, a look at the outer anatomy of the eye is essential. The tissue lining (mucus membrane) that covers the white surface of the eyeball and the inner folds of the eyelids is called conjunctiva. The conjunctiva is rich in blood vessels and contains more mast cells than the lungs. Located in the upper and outer portions of the eye, the lachrymal (tear) glands produce the watery component of tears. The cornea is the transparent sheath in front of the lens of the eye.
Unlike the hairs in the nose (cilia), the conjunctiva has no filtering system and it gets directly exposed to the environment when we open our eyes. Influenced by allergens, the allergy antibody, IGE, coats numerous mast cells in the conjunctiva. When exposed to the allergen again, the mast cell tends to release histamine and other mediators. It causes eye allergy resulting in itching, burning, and runny eyes. Although both eyes are usually affected, sometimes only one eye is involved, especially when only one eye is rubbed with an allergen.
Eye allergy can be of various types.
The most common among them is allergic conjunctivitis, also known as "allergic rhino conjunctivitis." In this condition, which is usually seasonal, the inflammation of the conjunctiva enlarges its blood vessels leading to redness, itching, and tearing of the eyes.
"Atopic keratoconjunctivitis" is another kind of eye allergy that mostly affects adolescent boys, especially those who had atopic dermatitis in early childhood. Its symptoms are intensely itchy red areas on the eyelids, heavy discharge from the eyes, and scales and crusts on the skin of the eyelid.
Although not very common, vernal keratoconjunctivitis is another form of eye allergy that usually affects preadolescent boys. It appears mostly in rural areas during late spring, in which the eyes become extremely itchy, sensitive to light, and the lids feel uncomfortable and droopy.
Irritation from a foreign body, such as contact lenses result in another type of eye allergy called giant papillary conjunctivitis. In this condition, large bumps are formed on the conjunctiva under the upper eyelid.
Contact eye allergy is in essence contact dermatitis of the eyelids.
It is commonly found among women as a result of allergic reactions to preservatives in eye products and cosmetics. In this condition, the eyelids may develop blisters, itching, and redness.
Most people having an eye allergy treat themselves and do so quite effectively with OTC products. However, if the problem refuses to go away, it is better to seek medical advice because, if left unattended or treated poorly, some of these conditions may even threaten their eyesight.
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