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.
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 available 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
Prescription eye drops 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.
- 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.
- 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.
- 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.
- 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.
- 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. 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.