Allergic conjunctivitis is inflammation of the conjunctiva caused by an allergic reaction to allergens in the air.
Allergic reactions caused by airborne allergens may inflame the conjunctiva.
Redness, itching, swelling, tearing, and stringy discharge are common.
Doctors base the diagnosis on the person's symptoms and on an examination of the eyes.
Various eye drops may help decrease symptoms and inflammation.
The conjunctiva (the membrane that lines the eyelid and covers the white of the eye) contains a large number of cells from the immune system called mast cells. Mast cells release chemical substances called mediators in response to a variety of allergens (such as pollens, mold spores, or dust mites). These mediators cause inflammation in the eyes, which may be brief or long-lasting.
An Inside Look at the Eye
Seasonal allergic conjunctivitis (hay fever conjunctivitis) and year-round or perennial allergic conjunctivitis (atopic conjunctivitis, atopic keratoconjunctivitis) are the most common types of allergic reaction in the eyes. Seasonal allergic conjunctivitis is often caused by mold spores or tree, weed, or grass pollens, leading to its typical appearance in the spring and early summer. Weed pollens cause symptoms of allergic conjunctivitis in the summer and early fall. (See also Seasonal Allergies.) Perennial allergic conjunctivitis occurs year-round and is most often caused by dust mites or animal dander. (See also Year-Round Allergies.)
Vernal keratoconjunctivitis is a more serious type of allergic conjunctivitis in which the allergen is not always known. The condition is most common among boys, particularly those aged 5 to 20 years who also have eczema, asthma, or seasonal allergies. Vernal keratoconjunctivitis typically reappears each spring and subsides in the fall and winter. Many children outgrow the condition by early adulthood.
Inflammation of the conjunctiva caused by a virus or bacteria, as opposed to an allergic reaction, is called infectious conjunctivitis.
Symptoms of Allergic Conjunctivitis
People with all forms of allergic conjunctivitis develop intense itching and burning in both eyes. Although symptoms usually affect both eyes equally, rarely one eye may be more affected than the other. The conjunctiva becomes red and sometimes swells, giving the surface of the eyeball a puffy appearance. The eyelids may become intensely itchy. Rubbing and scratching leads to eyelid skin redness, swelling, and a crinkly appearance.
DR P. MARAZZI/SCIENCE PHOTO LIBRARY
With seasonal allergic conjunctivitis and perennial allergic conjunctivitis, there is often a large amount of thin, watery discharge. At times the discharge is stringy. Vision is seldom affected. Many people have an itchy, runny nose.
With vernal keratoconjunctivitis, the eye discharge is thick, stringy, and mucuslike. Unlike other types of allergic conjunctivitis, vernal keratoconjunctivitis often affects the cornea (the clear layer in front of the iris and pupil), and in some people painful, small, open sores (corneal ulcers) develop. These ulcers cause deep eye pain with exposure to bright light (photophobia) and rarely lead to a permanent decrease in vision.
Diagnosis of Allergic Conjunctivitis
A doctor's evaluation of the symptoms and appearance of the eye
Doctors recognize allergic conjunctivitis by its typical appearance and symptoms. Tests are rarely needed or useful.
Treatment of Allergic Conjunctivitis
Eye drops
Avoiding known allergens (such as pollen, dust, and dander)
Allergic conjunctivitis treatment includes anti-allergy eye drops. Using chilled tear supplements and cold compresses and avoiding known allergens can help reduce symptoms.
Eye drops that have an antihistamine, such as ketotifen, may be enough for mild cases. This medication can be bought without a prescription. If Eye drops that have an antihistamine, such as ketotifen, may be enough for mild cases. This medication can be bought without a prescription. Ifketotifen is insufficient, prescription antihistamine eye drops (such as olopatadine or cetirizine) or mast cell stabilizers (such as nedocromil) may be effective. An alternative option for chronic symptoms is cyclosporine eye drops. is insufficient, prescription antihistamine eye drops (such as olopatadine or cetirizine) or mast cell stabilizers (such as nedocromil) may be effective. An alternative option for chronic symptoms is cyclosporine eye drops.
Nonsteroidal anti-inflammatory drug eye drops, such as ketorolac, help relieve pain. Corticosteroid eye drops have more potent anti-inflammatory effects. However, these eye drops should not be used for more than a few weeks without close monitoring by an ophthalmologist (a medical doctor who specializes in the evaluation and treatment [surgical and nonsurgical] of eye disorders) because they may cause increased pressure in the eyes (Nonsteroidal anti-inflammatory drug eye drops, such as ketorolac, help relieve pain. Corticosteroid eye drops have more potent anti-inflammatory effects. However, these eye drops should not be used for more than a few weeks without close monitoring by an ophthalmologist (a medical doctor who specializes in the evaluation and treatment [surgical and nonsurgical] of eye disorders) because they may cause increased pressure in the eyes (glaucoma), cataracts, and an increased risk of eye infections.
Antihistamines taken by mouth, such as fexofenadine, cetirizine, or hydroxyzine, may also be very helpful, especially when other areas of the body (for example, ears, nose, or throat) are affected by the allergies.Antihistamines taken by mouth, such as fexofenadine, cetirizine, or hydroxyzine, may also be very helpful, especially when other areas of the body (for example, ears, nose, or throat) are affected by the allergies.
