Getting a handle on ocular allergy

Optometric Management, Feb 2003 by D'Arienzo, Peter A, Berdy, Gregg J

A skillful differential diagnosis coupled with a targeted treatment plan brings relief Here's what works for these specialists.

Up to half of Americans suffer from some type of allergy, and many of these people endure itchy, red eyes from ocular allergies. Although ocular allergies usually aren't vision-threatening, they're uncomfortable and often interfere with daily activities.

Searching for relief, consumers bought about 41 million bottles of over-the-counter (OTC) allergy drops during 2000, but filled only 4 million prescriptions for ocular allergy drugs, according to the Prescription Audit by ScottLevin, Inc.

Obviously, many people are self-diagnosing and self-treating their. allergy symptoms - and not receiving adequate relief.

In this article, we'll share how we recognize and treat ocular allergies so that you can relieve patients' symptoms and rule out more serious conditions. We'll focus on the more common seasonal and perennial ocular allergies, which affect as many as 95% of allergy patients.

Pinpointing masqueraders

You probably have many allergy patients in your practice, but don't be too quick to chalk up an itchy, red eye to allergy. Your differential diagnosis should take into account other conditions that redden or irritate the eye. These may include dry eye, blepharitis and rosacea, as well as other "Potential Masqueraders" as described on page 9.

Although patients with ocular allergy usually have itching, tearing or redness, their symptoms may be more subtle. That's why it's important to take the time to obtain a detailed history and perform a thorough examination.

Begin by asking patients about other allergy symptoms. Most allergy patients have allergic rhinitis and the majority of those patients also have allergic conjunctivitis, but you need to question them about it. Ask:

* Do your eyes itch or bum?

* Do your eyes tear?

* Do your eyes become red?

* How long do the symptoms last?

* When do the symptoms occur?

* What triggers the symptoms?

Environmental irritants may cause itchy, red eyes, so ask patients whether they've used new cosmetics, soaps or laundry detergent. Ask about makeup and nail polish, which may irritate the eyes. Some agents, fragrances and binders in cosmetics break down on the skin surface into a formaldehyde derivative, producing contact dermatitis, which causes more severe symptoms than seasonal or perennial allergies; these symptoms are ocular, such as redness and itching.

Follow a detailed history with a careful evaluation in a well-lit examining room. If the lights are low, you may miss critical physical signs in making the differential diagnosis.

Before using the slit lamp, perform a thorough external evaluation, carefully examining the patient's facial features. Check the skin for signs of eczema or atopic dermatitis because these patients often have allergic conjunctivitis. Also, rule out viral conjunctivitis, infectious conjunctivitis and blepharoconjunctivitis. Remember, patients with infectious causes will have matting of eyelashes and purulent discharge.

When differentiating between the types of ocular allergies, keep in mind that patients with seasonal allergic conjunctivitis don't have tissue damage. Therefore, they wouldn't be expected to have pain, severe redness or decreased vision, which would be associated in patients with atopic keratoconjunctivitis and vernal keratoconjunctivitis, two less common, more severe ocular allergic conditions.

Seasonal allergies usually cause bilateral symptoms, but occasionally may cause unilateral symptoms. For example, your patient may have touched an allergy-triggering object, such as a cat, then rubbed his eye. If the irritation occurs in only one eye, it could be an allergic reaction, but more likely there's another nonallergic cause.

Developing a treatment plan

The patient's symptoms and your diagnosis will guide you to the best treatment. All oral antihistamines - even new-generation drugs such as loratadine (Claritin), cetirizine HCl (Zyrtec) and fexofenadine HCl (Allegra) - dry the eye, worsening ocular symptoms and confounding the differential diagnosis of the red, itchy eye. Consequently, many doctors avoid oral medications.

We prefer to treat topical diseases topically, using a nasal steroid for rhinitis and prescription anti-allergy eye drops for conjunctivitis. In a study comparing the combined use of fluticasone propionate (Flonase Nasal Spray) and fexofenadine HCl with the combination of fluticasone propionate and olopatadine HCl 0.1% (Patanol), the latter group fared better in regard to ocular and nasal symptoms. As an added benefit, the olopatadine eye drop is absorbed into the nasolacrimal system, reducing rhinitis symptoms due to its antihistaminic properties. Unlike oral medications, topical drops have no systemic side effects. Additionally, your patients can safely use topical drops for extended periods, as was proven in a 19-week study by Mark Abelson, M.D., Gregg Berdy, M.D., et al., in the Journal of Ocular Pharmacology and Therapeutics, in which they found pemirolast potassium provided extended efficacy and was as safe as a placebo.