Seasonal allergic conjunctivitis (SAC) is the most common form of eye allergy, with grass and ragweed pollens being the most important seasonal triggers. Perennial allergic conjunctivitis (PAC) is also very common, with animal dander, feathers and dust mites being the most important triggers.
Are there other symptoms of eye allergies?People with SAC usually note the onset of symptoms during the spring and fall, and frequently note symptoms of allergic rhinitis. Symptoms include itchy eyes, burning of the eyes and eye watering. In some cases, people notice sensitivity to the light and blurred vision. The eyes are usually red, and the eyelids may become swollen. When the inside of the eyelid (the conjunctiva) is also swollen, the eyes may have a watery, gelatinous-like appearance - this finding is called "chemosis".
PAC typically occurs year-round, although many people notice some seasonal flares to their symptoms. The severity of PAC is less than that of SAC, and PAC is much more likely to be associated with perennial allergic rhinitis.
How is allergic conjunctivitis diagnosed?The diagnosis of allergic conjunctivitis is made with a history of symptoms suggestive of eye allergies, an examination by a healthcare professional with findings consistent with conjunctivitis, and allergy testing showing seasonal or perennial allergies. A response to typical medications is helpful in the ultimate diagnosis of allergic eye disease, and failure to respond to medications may lead to a search for a different diagnosis.
What is the treatment of allergic conjunctivitis?If avoidance of allergic triggers fails to prevent symptoms of allergic conjunctivitis, some people notice mild benefit from cold compresses on the eyes, and eyewashes with tear substitutes. However, medications may be necessary to treat the symptoms. Medications for allergic conjunctivitis include oral anti-histamines and eye drops.
Oral anti-histamines. Many people with allergic eye disease will receive benefit from oral anti-histamines, such as over-the-counter loratadine (Claritin®/Alavert®, generic forms), and prescription cetirizine (Zyrtec®), fexofenadine (Allegra® and generic forms) and desloratadine (Clarinex®). Older, first-generation anti-histamines (such as Benadryl®) are also helpful, but are generally considered too sedating for routine use.
Over-the-counter eye drops. Medicated eye drops are available in over-the-counter and prescription forms. Over-the-counter eye drops for allergic conjunctivitis are currently only available in decongestant (Visine®, Naphcon®, generic forms of naphazoline), and decongestant/anti-histamine combinations (Visine-A®, Naphcon-A®, generic forms of naphazoline/pheniramine).
Decongestant eye drops (with or without anti-histamines) should only be used for short periods of time, as overuse can lead to conjunctivitis medicamentosa (characterized as rebound eye redness/congestion and dependence on the eye drops). These eye drops should not be used by people with glaucoma, and used with caution by people with heart or blood pressure problems.
The Food and Drug Administration recently approved ketotifen eye drops (currently available as prescription Zaditor®) for over-the-counter use. This medication is expected to be available by late spring 2007 under the brand name Alaway®. Ketotifen works by a dual action mechanism, with anti-histamine activity and prevention of the release of chemicals from mast cells. Unlike decongestant eye drops, ketotifen would not be expected to result in conjunctivitis medicamentosa with long-term use.