ALLERGY

An Overview of Allergy Treatment

Refer to this article the next time your patients ask you what they should use to treat their allergies.

BY RANDY MCLAUGHLIN, O.D., M.S.
April 2000

As the new millennium opens, it seems that the two questions most asked by patients of their eye care practitioner are: "How about that new laser refractive surgery," and "What type of eye drops should I use for my allergies?" This article will systematically answer the second question.

Allergic Conjunctivitis

Acute allergic conjunctivitis is a common complaint among patients. Type I allergic reactions are immediate, IgE-mediated reactions. Hypersensitivity occurs as a chain reaction. A patient is exposed to an antigen, which leads to degranulation of mast cells producing the release of histamine, which may then trigger the immediate allergic reaction.

For example, hay fever can be intensified by a patient wearing contact lenses. If patient symptoms are mild, I will prescribe currently available over-the-counter medications. The antihistamine-based medication Naphcon-A Solution (Alcon) or Opcon-A Solution (Bausch & Lomb), are widely utilized to treat mild allergic reactions. If these drops don't significantly reduce the patient's signs and symptoms, I will suggest a prescription medicaiton. The drug that I most widely prescribe for allergic conjunctivitis is Alcon's Patanol (olopatadine hydrochloride 0.1%), a topical antihistamine and mast-cell stabilizer. Patanol is an excellent therapeutic chioice for patients reporting mild to moderate itching without strong ocular signs. Patanol is prescribed b.i.d., so many contact lens wearers may utilize this medication before and after lens insertion. Alcon's Emadine (emedastine difumaratre 0.05%) is also a topical antihistamine, but is prescribed q.i.d. These two drops are my first choice in the treatment of acute allergies.

Another topical antihistamine, CIBA Vision's Livostin (levocabastine 0.05%), is a suspended medication that is prescribed q.i.d. and tapered after symptoms start to subside. It is effective in the reduction of itching associated with ocular allergy.

NSAIDs

Many practitioners choose to use nonsteroidal antiinflammatory drugs (NSAIDs) as their first choice in the treatment of acute allergic conjunctivitis. Allergan's Acular (keratolac tromethanmine) is the most popular NSAID approved for acute allergies. Furthermore, it was originally approved for inflammation control after cataract surgery. Acular has FDA approval for the treatment of seasonal allergies and is said to raise the sensory threshold of peripheral nerve endings, decreasing the itching sensation. Unfortunately, many patients complain that Acular stings upon instillation. It is used q.i.d. and the patient may decrease the instillation irritation by refrigerating the drops prior to use. CIBA Vision's Voltaren (diclofenac sodium 0.1%) decreases pain by reducing prostaglandin production. Both of these NSAIDs are used for many other ocular inflammatory complications besides ocular allergies.

Topical Ocular Steroids

If patients present with more intense symptoms and visible clinical signs of allergic conjunctivitis, topical ocular steroids may be added to the therapeutic regime. Bausch & Lomb's Alrex (loteprednol etabonate 0.2%) is a topical steroid used to treat ocular allergy. It is a corticosteroid suspension that is used q.i.d. and must be shaken before instillation. It's a site-specific steroid, which greatly reduces the incidence of more common steroid side effects, such as increased intraocular pressures and posterior subcapsular cataracts. B&L's Lotemax (loteprednol etabonate 0.5%) is a stronger sister steroid, used to treat more severe ocular complications. Other "mild" steroids sometimes used to treat ocular allergy are Allergan's FML (fluorometholone alcohol 0.1%) or Alcon's Flarex (fluorometholone acetate 0.1%).

Mast-Cell Stabilizers

More chronic allergies may require medication that are mast-cell stabilizers. These types of allergies are type IV, or cell-mediated, allergies. Cell-mediated, or delayed hypersenitivities, involve the interaction of T-lymphoctes. Ocular conditions include atopic keratoconjunctivitis, vernal conjunctivitis and blepharokeratoconjuctivitis induced by solution preservatives or contact lens deposits. Drugs required to treat these conditions are also effective in treating patients with confirmed seasonal allergies and giant papillary conjunctivitis. Allergan's Opticrom and
B& L's Crolom (cromolyn sodium 4%), as well as Alcon's Alomide (lodoxamide tromethamine 0.1%) are mast-cell stabilizers. These drugs have no antihistamine properties, so they are used routinely to keep the eye and the mast cells "stable."

Contact lens-induced giant papillary conjunctivitis (GPC) is also treated with mast-cell stabilizers. Patients use the medication q.i.d. for several weeks and taper to t.i.d. for the next week. Tapering of the medication will follow to b.i.d. and then one drop per day before cessation. Often patients are instructed to use mast-cell stabilizers in known season of ocular allergy.

We now have a very strong arsenal of allergic therapeutic medications, including modern oral antihistamines. These medications are very effective with few side effects. Most patient complaints can be managed by decreased contact lens wearing time, straightforward antihistamine therapy and/or mast-cell stabilizers. If symptoms are not relieved, you may want to institute NSAIDs or mild corticosteroids. 

Table 1: Ophthalmic Drug Guide.

References are available upon request to the editors at Contact Lens Spectrum. To receive references via fax, call (800) 239-4684 and request document #59. (Be sure to have a fax number ready.)