What is it?
Allergic conjunctivitis is part of a systemic atopic reaction to a systemic allergen. Usually seasonal, it tends to accompany upper respiratory tract symptoms, but sometimes it is the most bothersomeor onlymanifestation.
How does it present?
The main symptom is itching! The patient is constantly rubbing the eyes, but it doesn't help for long. The eyelids and conjunctiva become boggy, the , and there is a watery (sometimes mucoid) discharge. Both eyes are affected.
What to do?
If systemic antihistamines are not working, you have 5 categories of topical agents to choose from:
- Vasoconstrictors: These inexpensive over-the counter agents should be the first choice. Many brands are available containing antazoline phosphate 0.05%, naphazoline HCl 0.05%, oxymetazoline HCl, tetrahydrozoline HCl 0.05%, or phenylephrine 0.12%.
- H-1 receptor antagonists: More effective than the vasoconstrictors, but much more expensive. They should be the second line agents. The three principal choices are pheniramine maleate 0.3% (Naphcon), emedastine (Emadine), and levocabastine HCl 0.05% (Livostin).
- Nonsteroidal anti-inflammatory agents: ketorolac tromethamine 0.5% (Acular) and ketotifen 0.025% (Zaditor). These are adjunctive agents.
- Mast cell stabilizers: cromolyn sodium 4% (Crolom), nedocromil 2% (Alocril), pemilorast 0.1% (Alamast), and lodoxamide tromethamine 0.1% (Alomide). These are FDA-approved only for a specific type of allergic conjunctivitis called "vernal conjunctivitis." Use only if other classes of medications have failed.
- H-1 receptor antagonist and mast cell stabilizers: olopatadine hydrochloride 0.1% (Patanol), optivar, and elestan. These agents are more effective than the mast cell stabilizers alone.