Allergic Conjunctivitis

Symptoms and Treatment of Eye Allergies

Allergens such as pollen and pet dander may cause dilatation of blood vessels in the conjunctiva, the membrane covering the eye. The resulting reddening of the eyes is called allergic conjunctivitis.

Symptoms of eye allergies, or allergic conjunctivitis, include watery, itchy, red, sore, swollen and stinging of the eyes. Itching of the eyes is the most important symptom of allergic conjunctivitis. Without itching, it is much less likely that a person is suffering from allergies of the eyes. Both eyes are usually affected, although one eye may be more symptomatic than the other.

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.

Prescription eye drops. Eye drops in prescription forms are available in five types, based on how the medication works. Decongestant and decongestant/anti-histamine combination drops are also available in prescription forms, which are equivalent to other-the-counter formulations. Other than decongestant forms of eye drops, none of the prescription eye drops are associated with conjunctivitis medicamentosa with long-term use.

  1. 1) Anti-histamine eye drops. This medication, currently only available as emedastine (Emadine®), works well to treat eye allergies on an "as-needed" basis. Older forms of ant-histamine eye drops have been discontinued.
  1. 2) Mast cell stabilizer eye drops. These medications have been around for many years, and work well to prevent allergic conjunctivitis symptoms if used before allergen exposure. These are available as cromolyn (Crolom® and generics), nedocromil (Alocril® and generics), lodoxamide (Alomide®) and pemirolast (Alamast®). These medications are not as helpful when used on an "as needed" basis.
  1. 3) Anti-histamine/mast cell stabilizer dual-action eye drops. The newest generation of allergy eye drops is superior to either of the single action agents. This class of medication includes olopatadine (Patanol®), azelastine (Optivar®), epinastine (Elestat®) and ketotifen (Zaditor®). These medications block the effects of histamine and prevent mast cells from releasing the chemicals responsible for allergy symptoms.
    1. 4) Non-steroidal anti-inflammatory eye drops. Ketorolac (Acular®) is indicated for the treatment of allergic conjunctivitis, and works in a similar way as aspirin and ibuprofen. Those with aspirin sensitivity or intolerance should not use this medication.
    1. 5) Corticosteroid eye drops. Use of steroid eye drops can lead to severe complications if not used with caution and under the close supervision of a physician experienced in the use of these medications. Complications can include glaucoma, cataract formation, and severe eye infections. One type of steroid eye drop, loteprednol (Alrex®), is indicated for the short-term use (typically less than 7-10 days) of allergic conjunctivitis, but should be used with caution. These medications are usually only needed in severe cases of allergic conjunctivitis, and can act as a "bridge" to another class of medication as listed above.

      Allergen immunotherapy. Allergy shots have been shown to be especially beneficial in the treatment of allergic conjunctivitis, and are the only therapy available that changes the underlying problem of allergies, potentially curing the problem of eye allergies.


      1. 1) Ono SJ, Abelson MB. Allergic conjunctivitis: Update on pathophysiology and prospects for future treatment. J Allergy Clin Immunol. 2005; 115:118-22.
      1. 2) Bielory L. Allergic and Immunologic Disorders of the Eye. Part II: Ocular Allergy. J Allergy Clin Immunol. 2000; 106:1019-32.

      DISCLAIMER: The information contained in this site is for educational purposes only, and should not be used as a substitute for personal care by a licensed physician. Please see your physician for diagnosis and treatment of any concerning symptoms or medical condition.

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