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Allergic conjunctivitis Definition and Symptoms
Allergic conjunctivitis – A type I (IMMUNOGLOBULIN E [IgE]) HYPERSENSITIVITY REACTION, commonly called an allergic reaction, that affects the membranes that line the inner eyelids (conjunctiva). Sometimes the irritation also reddens the white part of the eye (sclera).
Allergic CONJUNCTIVITIS features red and swollen conjunctiva with excessive tearing and itching of the eyes and sometimes a white discharge. PHOTOPHOBIA (heightened sensitivity to light) is common. Because these symptoms also suggest viral or bacterial conjunctivitis (pink eye), which are infections, particularly when the discharge is yellow or green, a doctor should examine the eyes and assess the symptoms to make the correct diagnosis. Treatment differs according to the cause.
EYE irritation that interferes with vision, causes PAIN, or follows injury to the eye requires a doctor’s prompt evaluation.
The most common form of allergic conjunctivitis develops seasonally when airborne pollens are high. Some people develop allergic conjunctivitis with exposure to allergens such as dust and pet dander (especially cat dander) as part of a broader ALLERGY picture. People who have seasonal allergies (ALLERGIC RHINITIS), ALLERGIC ASTHMA, or other ATOPY conditions may have a GENETIC PREDISPOSITION for type I hypersensitivity reactions that puts them at higher risk for developing allergic conjunctivitis as well.
Allergic Conjunctivitis Treatment
Treatment for allergic conjunctivitis combines avoiding the responsible ALLERGEN with EYE drops that contain an antihistamine or, for severe symptoms, a corticosteroid (anti-inflammatory medication that suppresses the IMMUNE RESPONSE). ANTIHISTAMINE MEDICATIONS neutralize the histamine responsible for the allergic response. Systemic antihistamine medications (allergy relief products) may also help, especially when there are accompanying allergy symptoms such as allergic rhinitis. Natural tears eye drops can restore moisture to eyes that are scratchy and dry. Allergic conjunctivitis generally resolves when exposure to the allergen ends, which may be the end of allergy season when seasonal allergies (hay fever) are responsible.