State of the Science in Ocular Allergies

There are many effective agents for this prevalent condition.

By Walter O. Whitley, OD, MBA, FAAO

Ocular allergies are extremely prevalent. It is estimated that up to 60 million Americans have allergies, and 24 million have ocular symptoms suggestive of ocular allergies.1 It is the fifth leading chronic disease in the United States and may account for up to 8 million office visits per year and about $5.9 billion in direct costs.1

AT A GLANCE

• Management of ocular allergies can be complex, as many of the signs and symptoms crossover with DED and blepharitis.

• A patient’s history is essential for a proper diagnosis, and its also relevant to ask about symptoms, in particular itching, and direct the examination toward the location of the discomfort.

• One of the keys to managing ocular allergy is avoiding its triggers. Therapy centers on the use of combination mast cell-antihistamine agents because of their proven efficacy, safety and convenience. In some situations it may be advantageous to consult with an allergist.

Fortunately for patients, there are very effective agents for the local treatment of ocular allergies. Yet, the management of ocular allergies should not rely solely on empirical treatment, as many of the signs and symptoms crossover with those of common ocular surface disease states, such as dry eye disease (DED) and blepharitis. In fact, the correct management of ocular allergy starts with the proper diagnosis, which includes an appropriate use of testing and encompasses a graduated approach to therapy that is inclusive of avoidance and palliative care measures.

DIAGNOSIS

When considering ocular allergy, the patient’s history is essential for proper diagnosis, specifically, practitioners should ask direct questions aimed at identifying how the patient’s eyes feel. Separate from the reason for the patient’s office visit, it is almost universally relevant to ask about itching, burning, fluctuation of vision throughout the day, does the patient need to use drops, is there bothersome redness, etc. Of these, ocular itching is the hallmark of ocular allergy.

If there is itching, the next steps in the examination should be directed toward determining its location; is it nasal and associated with the nasal canthus (more typical of allergy) or is it along the lids (suggestive of blepharitis). Another question to ask is whether the symptoms appear unilaterally or bilaterally; the latter is more typical of allergy—however, it is important to note that not all ocular allergy is necessarily bilateral in presentation.

Common ocular signs of allergic conjunctivitis include chemosis, eyelid swelling, conjunctival papillae, and no preauricular lymphadenopathy. An ancillary bit of information that may be useful in making the diagnosis is the current season. Although the concept of an “allergy season” is becoming less relevant, pollen is more typical in the spring, grasses in the summer, and weeds in the fall.

Role of Testing

Because the signs and symptoms of DED, allergy, and blepharitis overlap (and because they can be present at the same time), differentiating the exact etiology of ocular inflammation is crucial for directing therapy. Therefore, point-of-care testing is becoming increasingly relevant in eye care, and several companies either have tests or are developing them for use in differentiating ocular disease (InflammaDry [Rapid Pathogen Screening], TearLab Osmolarity System, Sjö and Doctor’s Allergy Formula [both from Bausch + Lomb]).

There are only two currently available tests for ocular allergy. One test measures both the quantity and quality of the tears via levels of lactoferrin and immunoglobulin E (IgE) levels (TearScan; Advanced Tear Diagnostics). Lactoferrin is a protein that exhibits a unique combination of antimicrobial, antiviral, and antiinflammatory properties. Low lactoferrin levels directly correlate to dry eye syndrome caused by aqueous deficiency; as such, low lactoferrin levels indicate dry eye syndrome and depressed ocular immunity.2 In the allergic cascade, IgE binds to allergens and triggers the degranulation of mast cells that cause inflammation.3 When IgE is present, it indicates a diagnosis of allergic conjunctivitis with levels of IgE increase corresponding with the severity of the allergic response.

The US Food and Drug Administration-approved TearScan test takes about 2 to 3 minutes to perform, and its results can help differentiate the etiology of ocular surface disease, including aqueous deficient versus evaporative DED and/or ocular allergy. In addition to the diagnostic capabilities, the technology allows you to monitor efficacy of treatment as well as patient compliance to treatment measures. In the near future, there is likely to be additional objective point of care allergy tests to improve our diagnostic accuracy as in the case of DED.

Serum and skin testing may have a role for certain patients, especially to help guide patients’ education regarding allergen avoidance. Such testing can also help shore up the diagnosis so that appropriate therapy can be selected. Serum and skin testing have relative pros and cons that should be understood.

Testing may be an underappreciated aspect of managing ocular allergy. As important as it is to rule in allergies, it is equally useful to be able to rule out the condition as a potential cause of ocular surface irritation. One diagnostic allergy test that we have found beneficial is the Doctor’s Allergy Formula (Bausch + Lomb) which improves our diagnosis and management of allergies. In this allergy test, patients are exposed to 60 of the most common allergens specific to our area (regional profiles vary). If positive, we discuss the importance of avoiding/modifying the environment to minimize their symptoms. Also, we prescribe appropriate topical/nasal/systemic therapies as indicated. There are occasions where patients test negative to any of the allergens. Although patients may still have an allergy, they are more likely suffering from other ocular surface diseases such as blepharitis or DED. In these cases, we have patients discontinue their systemic allergy medication which is exacerbating their symptoms while aggressively treat their ocular surface.

TREATMENT

The treatment of ocular allergy truly starts with its identification, because counseling patients to avoid triggers is essential: If you remove the trigger, the allergic cascade never starts. Unfortunately, full avoidance may not be possible. In terms of active treatment, most therapeutic plans progress in a stepwise fashion, with the need to graduate to more sophisticated measures determined by a lack of response to previous therapy.

Therapy for ocular allergy centers on use of combination mast cell-antihistamine agents because of their proven efficacy, safety and convenience. The newest agent to the market is Pazeo (olopatadine HCl 0.7%; Alcon) which can be used once a day and is approved for the treatment of itch for 24 hours. One popular strategy for more severe allergic responses is to start the patient on steroidal agents such as Alrex (loteprednol etabonate 0.2%; Bausch + Lomb), either alone or concurrently with combination drops, to quiet the inflammation, and then to taper off and add the combination agent for longer-term maintenance.

In some situations it may be advantageous for the eye care provider to consult with an allergist to coordinate the comanagement of allergic conditions. For example, patients with sinus and throat symptoms with or without headaches may require systemic immunotherapy to address what may be a serious underlying condition.

CONCLUSION

Although it is useful to know what to do in more severe manifestations of ocular allergy, by and large, most patients with likely ocular allergies are treatable with combination agents. All patients, however, should be counseled on palliative and preventive care measures. Here are 12 allergy tips that I learned from John Sheppard, MD, MMsc which should be shared with patients diagnosed with ocular allergies:

• never rub your eyes
• wash your hands
• use allergy-free pillows
• stay indoors
• use drops for eyes, sprays for nose
• avoid vasoconstrictors
• chill your drops
• use cool compresses
• apply allergy drops proactively
• keep the pets out of house or bedroom
• know and avoid your personal allergens
• be aware of resources such as pollen.com, weather.com, and webmd.com, which are useful for knowing what the pollen counts are in your area, as well as what is the most predominant pollen type

It may not always be possible for patients to follow all 12 steps, however, it is a basic fact that if the allergen is removed, the allergic cascade never begins. As a result, managing ocular allergy really does begin with recognition and proper diagnosis. n

1. Raizman M, Luchs J, Shovlin J, Wolf R. Ocular allergy: a scientific review and expert case debate. Rev Ophthalmol. May 2012. http://www.reviewofophthalmology.com/continuing_education/tabviewtest/lessonid/108270.

2. Ohashi Y, Ishida R, Kojima T, et al. Abnormal protein profiles in tears with dry eye syndrome. Am J Ophthalmol. 2003;136:2:291-299.

3. Broide DH. Molecular and cellular mechanisms of allergic disease. J Allergy Clin Immunol. 2001;108(2):S65-S71.

Walter O. Whitley, OD, MBA, FAAO
• Director of Optometric Services, Virginia Eye Consultants, Norfolk, Virginia
• (757) 961-2944; wwhitley@vec2020.com
• Financial disclosure: consultant to Alcon and TearScience