Uncovering Ocular Allergies
Questionnaires can be the first step in providing insight into a patient's undiscovered allergies.
WILLIAM BERGER, M.D.

The great number of individuals affected by allergies translates into a significant influence on society as a whole. Ocular allergies affect an estimated 20% of the general population and over 90% of these cases are seasonal and/or perennial.¹ In the United States alone, the prevalence of seasonal and perennial allergic conjunctivitis is 22 million.² These numbers are only a small percentage of the actual number of persons affected by allergy in all of its forms.^3,4 A recent study of rhinitis patients revealed that over 90% had previously undiagnosed ocular symptoms that were affecting their quality of life.⁵

Ocular allergies are perhaps one of the most common components of allergic disease encountered by allergists and primary care physicians and are likewise commonly identified by ophthalmologists as a complaint of their patients. Determining the presence of an allergy with such an uncooperative and often invisible presentation is both time consuming and difficult. Yet, pinpointing the specific allergic condition and the best treatment option is crucial to improving quality of life issues for the patient.

There are various types of allergic conjunctivitis, including severe and chronic forms, but seasonal and perennial allergic conjunctivitis are the most common. The vast incidence of acute allergic conjunctivitis emphasizes its clinical significance, and this form of allergy typically manifests itself as a series of discrete allergic episodes, triggered by exposure to specific allergens and lasting a matter of hours per episode, rather than persisting as a chronic process as with severe forms of allergies such as atopic and vernal keratoconjunctivitis.

On the cellular level, acute allergic conjunctivitis is the clinical manifestation of IgE-stimulated mast cell degranulation. The array of pre-formed mediators released upon mast cell degranulation, histamine being the most important, is responsible for inducing the clinical signs and symptoms of an allergic reaction. This reaction is characterized by the classic symptom, itching, along with hyperemia, chemosis, lid edema, mucous discharge and tearing.

There exists a phenomenon, referred to as the "itch-rub cycle," that enhances this intense redness and swelling. The itching of an allergy creates the desire to rub the eyes, and this manual stimulation can induce further release of mast cell-derived mediators, prolonging the signs and symptoms of the allergic reaction.⁶

Digging Deeper

It is critical to recognize the episodic pattern in the diagnosis of an allergy since the patient can be completely asymptomatic during the examination in the environment of a physician's office. If a patient's annual exam is in the winter months, but their allergy is to grasses in the spring, a patient will not present with active signs and symptoms.

Looking within your practice, you may find other unidentified cases of ocular allergy. In many instances, allergies may be something a patient is not asking about actively, but it is something that is bothering them. By asking a few simple questions in the form of a preliminary allergy questionnaire, extra patient care is provided and a larger allergy patient population can be identified.

Many allergy symptoms overlap with other conditions and the intensity of the symptoms can help to differentiate conditions. In the case of itching, this question would help differentiate between the true itching of allergies and the burning, foreign body sensation and irritation associated with dry eye. Another important aspect to consider is the timing of the symptoms. When do the symptoms occur? During what part of the day? During which season? These questions will determine whether or not the signs and symptoms correspond to allergen exposures in the surrounding environment (i.e., outdoors, at work or near pets).

Another important question to include should be about the use of systemic antihistamines or any over-the-counter (OTC) products or eye drops. Often this question actually provides a good starting point, as you can then work backwards to determine when, why and for what symptoms the patient is taking these medications. If a patient is taking an OTC medication for an allergy symptom, there is a good chance that a physician can provide a prescription for something even more effective.

Treatment

Beginning an allergy treatment regimen is significant at any point, whether it is for current allergies or as a preventative measure. It is important for the physician to keep in mind that there are differences between the many available treatments for ocular allergies, and not just one will suit each patient perfectly. The categories of medication differ according to the mechanism of action, frequency of dosing, safety, efficacy and comfort. By identifying the presence of allergies, more potent prescription treatment options with a longer duration of action can be provided by the physician as opposed to the more limited OTC options.

OTC eye drops are typically antihistamines or antihistamine/vasoconstrictor combinations, which offer quick onset, though short duration of action. The duration typically ranges from 2 to 4 hours and indications limit dosing to 4 times per day. These medications provide temporary relief but do not have the duration and potency of the options available with a prescription agent. Similarly, many systemic OTC antihistamine options have been known to cause ocular drying, and thus potentially contribute to symptoms associated with allergy such as redness and chemosis. By identifying the allergic condition and establishing the needs of the individual, more effective options can be implemented.

The most recent class of prescription ocular allergy medications that are very effective at treating allergies includes the dual action agents, which are combination antihistamine and mast cell stabilizing drugs. Blocking the allergic reaction at 2 points provides for greater prevention against the signs and symptoms of ocular allergy. This class has comfortable formulations, rapid onset, and long duration of action with twice daily dosing being the typical indication. Agents within this class include Patanol (olopatadine 0.1%, Alcon), Zaditor (ketotifen 0.025%, Novartis), Elestat (epinastine 0.05%, Inspire/Allergan), and Optivar (azelastine 0.05%, Medpointe).

At the present time, olopatadine 0.1% is the only eye drop of this category indicated for the relief of all the signs and symptoms of ocular allergies. A recent study revealed that including olopatadine 0.1% in patients' existing systemic or nasal medication regimen had significant benefit in improving quality of life.⁵

Implementing a two or three item questionnaire can serve as an efficient initial filter and provide a basis for physicians to further narrow their diagnosis and eventual treatment assignment. There is little or no time added to the actual examination time, but the questionnaire provides the opportunity for additional patient care. The questionnaire can not only provide for new allergy diagnosis, but may also provide physicians insight into other possible conditions.

By becoming aware of the allergy issue, patients will have more control over their ocular health and may be provided with new options that had not previously been available or known to them. Contact lenses, for example, may become an option for those patients who are candidates and get their allergies under control. The implementation of an allergy questionnaire has the potential to reap significant benefits for both the health of your patients as well as your practice.

William Berger, M.D., is clinical professor, at the Department of Pediatrics, Division of Allergy and Immunology, University of California, Irvine. He can be e-mailed at WEBerger@uci.edu.

References

1. Abelson MB, Chapin MJ. Current and Future Topical Treatments for Ocular Allergy. Comp Ophthalmol Update 2000; 1: 303-317.

2. Leonardi A. Pathophysiology of allergic conjunctivitis. Acta Ophthalmol Scand. 1999; 77 (suppl): 21-3.

3. Hesselmar B, Aberg B, Eriksson B, Aberg N. Allergic rhinoconjunctivitis, eczema, and sensitization in two areas with differing climates. Pediatr Allergy Immunol. 2001; 12(4): 208-215.

4. Asher MI, Barry D, Clayton T, Crane J, et al. The burden of symptoms of asthma, allergic rhinoconjunctivitis and atopic eczema in children and adolescents in six New Zealand centres: International Study of Asthma and Allergies in Childhood (ISAAC) Phase One. New Zealand Medical Journal. 2001; 114: 114-120.

5. MacDonald N, Gomes PJ, Abelson MB, Berger WE et al. Quality of life in rhinoconjunctivitis sufferers and the effects of topical ocular therapy. Presented at the Association for Research in Vision and Ophthalmology meeting: May 1-5, 2005; Fort Lauderdale, Fla.

6. Schafer T, Ring J. Epidemiology of allergic diseases. Allergy. 1997; 52 (suppl 38):14-22.