Allergic conjunctivitis refers to eye inflammation resulting from an allergic reaction to substances like pollen or mold spores. We look at the condition and ways to provide relief for patients.
In the Gell and Coombs classification system for various immunologic hypersensitivity reactions, five types of reactions are recognised. The major type I hypersensitivity reactions involving the conjunctiva are commonly referred to as allergic conjunctivitis and are further subclassified into seasonal allergic conjunctivitis and perennial allergic conjunctivitis. Far less common are the more severe forms of allergic conjunctivitis, including atopic keratoconjunctivitis, giant papillary conjunctivitis, and limbal and tarsal vernal keratoconjunctivitis.
Diagnosis of allergic conjunctivitis is generally made by thorough history and careful clinical observation. The presence of an antigen triggers the allergic cascade, and, thus, avoidance of the offending antigen is the primary behavioral modification for all types of allergic conjunctivitis. In other respects, management of allergic conjunctivitis varies somewhat according to the specific subtype.
Allergic conjunctivitis can be treated with a variety of drugs, including topical antihistamines, mast cell stabilisers, nonsteroidal anti-inflammatory drugs, and corticosteroids. Allergic conjunctivitis comes in two main types:
Acute allergic conjunctivitis
This is a short-term condition that is more common during allergy season. Your eyelids suddenly swell, itch, and burn. You may also have a watery nose.
Chronic allergic conjunctivitis
A less common condition called chronic allergic conjunctivitis can occur year round. It is a response to allergens like food, dust, and animal dander. Burning and itching of the eyes and light sensitivity are common symptoms.
What causes allergic conjunctivitis?
You experience allergic conjunctivitis when your body tries to defend itself against a perceived threat. It does this in reaction to substances that trigger the release of histamine, a potent chemical your body produces to fight off foreign invaders. Some of the substances that cause this reaction are:
- Household dust
- Pollen from trees and grass
- Mold spores
- Animal dander
- Chemical scents (e.g. household detergents or perfume). Some people may also experience allergic conjunctivitis in reaction to certain medications or substances dropped into the eyes, such as contact lens solution or medicated eye drops.
Red, itchy, watery, and burning eyes are common symptoms of allergic conjunctivitis. Patients may also wake up in the morning with puffy eyes.
In more troublesome cases, home care may not be adequate. The following are recommended:
- An oral or over-the-counter antihistamine to reduce or block histamine release
- Anti-inflammatory and/or anti-inflammation eye drops
- Eye drops to shrink congested blood vessels
- Steroid eye drops (only in severe cases).