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Issue: May 2008 Recognizing Ocular Allergies

Recognizing Ocular Allergies

Experts weigh in on how to differentiate ocular allergy from dry eye.

Paul M. Karpecki, O.D.: Statistics show that 1 in 5 Americans suffer from allergies,1 and that allergies are the third most chronic condition among children.2 Most allergy patients say their symptoms affect their lifestyle — everything from sleeping to driving. And many suffer from dry eyes.

Despite this prevalence, most doctors minimize or overlook the severity of the quality of life issues related to ocular allergy. This may be because we're so accustomed to seeing the signs and symptoms in our daily practices or perhaps it's because of the ongoing challenge of distinguishing the condition from dry eye.

Today in our panel discussion, we'll review the common, overlapping symptoms associated with ocular allergy and dry eye and the strategies to help us make differential diagnoses, so we can improve the treatment and management of our patients.

Overlapping symptoms

Ian Benjamin Gaddie, O.D.: Symptoms of dry eye and ocular allergy frequently overlap.3 A prudent first step in determining if a patient has an ocular allergy is to prescribe an antiallergy agent, such as epinastine HCl ophthalmic solution 0.05% (Elestat, Inspire Pharmaceuticals).4 If this medication relieves symptoms quickly, you'll know the patient has an ocular allergy. If the agent doesn't relieve symptoms, or exacerbates them, then you know the patient may have dry eye.

Symptoms of seasonal allergic conjunctivitis, such as itching and tearing, often are confused with dry eye.

Kelly K. Nichols, O.D., M.P.H., Ph.D: Itching is an important, telltale symptom of ocular allergy, but it's also commonly reported in dry eye.5,6 So I ask patients to characterize the itch as severe, chronic or seasonal in addition to describing a cluster of symptoms during certain times of the year. The patient's answer helps me determine if he's suffering from dry eye or ocular allergy.

"Symptoms of dry eye and ocular allergy frequently overlap. A prudent first step in determining if a patient has an ocular allergy is to prescribe an antiallergy agent."

— Ian Benjamin Gaddie, O.D.

Douglas K. Devries, O.D.: To make a distinction between ocular allergy and dry eye symptoms, I look for chemosis, especially the glossy appearance of the eye, which is a hallmark of ocular allergy.

Dr. Gaddie: Louisville, Ky., where I practice, is considered one of the allergy capitals of the world. So I ask all patients if their eyes itch. They don't always have a chemotic or runny eye. However, tearing is a significant symptom that's associated with ocular allergy and dry eye. In allergy patients, I often see lacrimation, especially when I use the slit beam. I have several patients who are using a topical allergy medication in combination with dry eye therapy for the long term.

Effects of OTC drugs

Dr. Karpecki: Our differential diagnoses also have been affected by the recent increase in the number of over-the-counter (OTC) oral antihistamines. More than 50% of these medications, which can cause ocular dryness, now are sold over the counter, and many allergy patients use them. How does this affect our patients, especially contact lens wearers?

Dr. Devries: You have to ask specific questions on your patients' entrance survey:

  • Do you buy OTC products to treat seasonal allergies?
  • Do you buy products to treat sinus conditions?
  • Do you use drops to treat the redness in your eyes?

Dr. Gaddie: When patients tell me they're taking an oral antihistamine, I say, "So you have allergies? Do your allergies bother your eyes as well?" They often say yes. They think the oral antihistamine has a significant effect on their allergic conjunctivitis, when in fact, it doesn't. So, in this case, you have an excellent opportunity to prescribe an antiallergy topical treatment. If the patient has dry eye symptoms, you may ask him to discontinue the oral antihistamine, especially if he's taking one that contains a decongestant, which may worsen dry eye symptoms.

Lissamine green dye reveals dead cells on the ocular surface — an early indicator of dry eye.

Diagnostic strategies for dry eye

Dr. Karpecki: A golf pro with a history of dry eye presents with classic symptoms of itching and chemosis. What steps would you take to confirm his previous dry eye diagnosis?

Dr. Nichols: I take a step-wise approach to establish the underlying condition. I instill fluorescein to determine tear film breakup time. After the pooling has subsided, I use a yellow Wratten filter to look for diffuse fine staining, which often is associated with many dry eye patients. Next, I instill Lissamine green dye for at least a minute. Then I evaluate the conjunctiva and the palpebral conjunctival lid margin, looking for early dry eye staining on the conjunctiva. In contact lens patients, I may not see fluorescein staining of the cornea as an early indicator of dry eye, only the Lissamine green staining of the conjunctiva. I also invert the superior lid and evaluate the inside of the lid margin for a mild papillary reaction, a common finding in both allergy and dry eye patients.

"To make a distinction between ocular allergy and dry eye symptoms, I look for chemosis, especially the glossy appearance of the eye, which is a hallmark of ocular allergy."

— Douglas K. Devries, O.D.

Dr. Devries: I look for conjunctival chemosis, which often accompanies itching. To determine the dry eye component, I evaluate the quantity and quality of the tear meniscus by positioning a small conical beam from the slit lamp on the lower temporal aspect of the lid margin. Then, I instill fluorescein to determine if any staining is present and measure tear film breakup time. Patients often will experience a burning sensation before the tears visibly break up, indicating the tear film breakup time.

Next, I perform Lissamine green staining. I find there's a high correlation between dry eye symptoms and subtle Lissamine green staining. In addition, I express the meibomian glands, checking for inflammation and evaluating the oil layer and evaporative component of dry eye.

After the established diagnosis

Dr. Karpecki: Now that we've discussed differential diagnoses of ocular allergy and dry eye, we'll review how to manage the allergy patient. OM

  1. CDC Fast Facts A-Z. Vital Health Statistics, 2003.
  2. "Chronic conditions: A challenge for the 21st century." National Academy on an Aging Society, 2000.
  3. Doughty M, Blades K, Ibrahim N. Assessment of the number of eye symptoms and the impact of some confounding variables for office staff in non-air-conditioned buildings. Ophthalmic and Physiological Optics. 2002;22:143-155.
  4. Kamei C, Akagi M, Mio M, et al. Antiallergic effect of epinastine (WAL 801 CL) on immediate hypersensitivity reactions: (I). Elucidation of the mechanism for histamine release inhibition. Immunopharmacol Immunotoxicol. 1992;14:191-205.
  5. Doughty MJ, Fonn D, Richter D, et al. A patient questionnaire approach to estimating the prevalence of dry eye symptoms in patients presenting to optometric practices across Canada. Optom Vis Sci. 1997;74:624-631.
  6. Moss SE, Klein R, Klein BE. Prevalence of and risk factors for dry eye syndrome. Arch Ophthalmol. 2000;118:1264-1268.
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