American Academy of Ophthalmology Web Site: www.aao.org
Pollen, Dust & Mold: Seasonal Allergies Assault the Eye
For allergy sufferers, drier air and exploding springtime pollen counts wage war on the itchy, inflamed ocular surface.
Combine the reproductive passions of flowers and fungi with some human immunoglobulin, sprinkle in mast cells and histamines, and you have a recipe for patients seeking your help each spring.
Plant pollen and mold spores initiate the allergic response when they make errant landfall on the mucosa of the eyes, nose and lungs. As the allergens combine with immunoglobulin E (IgE), which is normally present at very low levels in the body, mast cell membranes become sensitized, histamine is released and symptoms appear almost immediately for seasonal sufferers, who tend to possess greater-than-average quantities of IgE. They also tend to have allergy histories. “For those with preexisting allergies, the risk for developing seasonal allergies may be higher than for someone who has no other allergies. These patients may have an increased susceptibility to the wide range of allergens in the environment,” said William B. Trattler, MD, a cataract, cornea and refractive surgeon in private practice in Miami.
The spring and summer allergy episodes, however, are a bigger problem than chronic varieties. “Seasonal allergic conjunctivitis is usually a more severe problem for patients than perennial allergies,” said Michael S. Blaiss, MD, an allergist in private practice at Allergy and Asthma Care and clinical professor of pediatrics and medicine at the University of Tennessee in Memphis.
Seasonal allergies affect more than 35 million Americans each year and can have a tremendously negative impact on an individual’s quality of life. Tree pollens in April and May, grass pollens in June and July and mold spores and weed pollens in July and August add up to a five-month barrage of eye-irritating allergens.
On a larger scale, allergy can significantly affect the economy. More than $250 million per year is lost due to absenteeism in the United States alone.1 And health care costs associated with allergy management are estimated to be nearly six billion dollars annually, a quarter of which is related to prescription and over-the-counter medication use.2
Eye, nose and throat siege. Triggered by the same allergens that cause intermittent allergic rhinitis, seasonal allergic conjunctivitis is the most commonly occurring ocular allergy. A part of a wide array of allergic conditions that involve inflammation of the conjunctiva, seasonal allergic conjunctivitis is characterized by a combination of ocular itching, inflammation, watering and redness.
Allergic conjunctivitis frequently occurs in conjunction with allergic rhinitis. “The symptoms tend to go hand in hand,” said Dr. Blaiss. “Approximately 80 to 90 percent of patients, if questioned properly, will report ocular problems along with nasal symptoms. This is particularly true when patients seek treatment during the spring.” The comorbid nasal symptoms include runny nose, sneezing, coughing, difficulty breathing, itchy nose, mouth or throat, and headaches from sinus congestion. “For the remaining 10 to 20 percent of patients, the allergen is just not having a major enough effect on the eyes that it leads to symptoms. Or, the symptoms are so minor that the patient has learned to live with them,” said Dr. Blaiss.
Although allergies can develop at any age, the pediatric population comprises more than half of all reported cases; 80 percent of patients are under age 30. Genetic and environmental factors play a significant role, and more than likely a combination of both is necessary for symptom onset.
Clues to a Diagnosis
Because the symptoms of seasonal allergy can resemble those of dry eye disease, diagnosis can be a challenge. Although a patient may have only seasonal allergies or only dry eye disease, there is a good possibility that both conditions are present. As the most common eye disease, dry eye disease frequently complicates the diagnosis and management of other ocular surface disorders.
“The best demographic information we have is that each of these conditions affects about 20 percent of the population. A natural overlap complicates matters,” said Michael A. Lemp, MD, clinical professor of ophthalmology at Georgetown and George Washington Universities. “You want to distinguish between dry eye and allergies because the treatment is going to be quite different. You also want to differentiate patients who are suffering from both conditions. It’s not simply differentiating one from the other, it’s also identifying patients with comorbid symptoms.”
Itchy = allergy. Ocular itching is the most distinguishing feature when seasonal allergic conjunctivitis is suspected. The annual recurrence of symptoms is also a significant clue, Dr. Trattler said. Gleaning a complete history from the patient is essential: Do you have a family history of allergies? Do your eyes itch and do your eyelids swell? Do your eyes tear or become red and inflamed? What seems to trigger the symptoms and how long do they last?
In addition to slit-lamp examination, observing the eyelids, conjunctiva and the papillary-follicular response provides information about an allergic reaction. “Conjunctival edema can be an indicator of an acute episode,” said Steven E. Wilson, MD, professor of ophthalmology and director of corneal research at the Cole Eye Institute at the Cleveland Clinic.
How dry, that eye? A careful visual examination will also help with ruling out dry eye. “A patient presents with itching, burning and tearing. The conjunctiva is slightly swollen and it is very pale—the typical appearance of allergy,” said Dr. Lemp. “But the question is: Is there an underlying dry eye component, too? You probably do not need to conduct a Schirmer test with these patients because you already see their tearing and can rule out aqueous-deficient dry eye. A careful examination of their lids to determine whether they have evidence of a meibomian gland dysfunction is important, however. When present, evaporative dry eye may occur because the tears are evaporating too quickly, thus depleting the lipid layer and a providing significant clinical indicator for differentiating between allergy and dry eye.”
Further complicating diagnoses are the potential masquerades. (See “Seasonal, Sicca or Serious?”) “If the symptoms are unilateral, seasonal allergy can almost always be ruled out,” said Leonard Bielory, MD, professor of medicine, pediatrics, ophthalmology and visual sciences, director of clinical research and development, and director of the division of allergy, immunology and rheumatology at the University of Medicine & Dentistry of New Jersey in Newark.
If seasonal conjunctivitis is diagnosed, patients may gain at least some control over their discomfort by understanding what contributes to their particular allergies:
More aggressive measures should be considered for patients who do not experience relief by simply avoiding allergens.
Better living through chemistry. Prior to seeking assistance from an ophthalmologist or allergist, patients with mild to moderate symptoms often rely on over-the-counter eye drops and oral medications for relief. Artificial tears, ocular decongestants/antihistamines and oral antihistamines in various combinations are able to keep the symptoms at bay for some allergy sufferers. Others will want more comprehensive medical attention. “There are a whole host of products available with three or four basic mechanisms of action—some with dual mechanisms,” said Dr. Lemp. “For patients with mild to moderate symptoms, antihistamines or a combination antihistamine/mast cell stabilizing drug tend to be the treatment of choice.”
Sampling treatment options.. Matching the correct medication for each patient is a matter of symptom evaluation. “In many of these patients, we may start with an oral antihistamine to see if it will control the problem,” said Dr. Blaiss. “Another option is intranasal corticosteroids, one of which has an indication for decreasing the symptoms of both seasonal allergic rhinitis and seasonal allergic conjunctivitis. The agents that work the best for patients with moderate to severe ocular symptoms are the multiaction medications, Optivar, Elestat and Patanol, for example. These agents have H1- and H2-blocking mechanisms as well as mast-cell stabilizing and anti-inflammatory effects.”
“Topical cyclosporine can be tremendously beneficial in alleviating symptoms, and ophthalmologists should feel comfortable using it in patients who may need extended treatment. Some patients have been using it for seven years now, since the clinical trials for it began, with no major side effects reported. You can’t beat that for a safety profile,” said Dr. Wilson. “There are a number of patients who find one of the main benefits of cyclosporine treatment is that once the dry eye and the allergy improve, they have a much better wearing time with their contact lenses.”
Have the big guns handy. In the situations unresponsive to all those measures, treatment with topical corticosteroids and/or immunotherapy should be used.
“Some patients are just more refractory to treatment than others. In severe cases, corticosteroids may be necessary to reduce the inflammation if you are not making headway with other treatments,” Dr. Lemp said. However, prolonged use of these agents can result in serious side effects, including the development of glaucoma and cataracts, so patients should be monitored closely.
Patients should seek assistance from an allergist when the problem is not easily controlled or isolated to the eye and nose. “Systemic treatment is almost a must for some patients. Follow-up by an allergist could have a tremendous effect on alleviating symptoms,” said Dr. Wilson.
Dr. Trattler agreed: “Any time that a patient has symptoms that are problematic to the point that their activities of daily living are impeded, you should refer the patient to an allergist to determine whether immunotherapy might be helpful.”
The challenge of comorbidity. Just as differentiating seasonal allergic conjunctivitis from dry eye disease can be tedious, treatment for the combined disorders may prove to be complicated. “It’s a challenge to manage patients with both allergy and dry eye disease because the allergens in the environment continue to encounter the tear film. If the tear film is very low, it does not effectively wash away the allergens, and patients get more exposure because the allergen remains on the eye. As a result, there is a more vigorous allergic response,” said Dr. Trattler.
Equally important to consider are the drying effects that oral antihistamines can have on dry eye disease. In some cases the effects can significantly exacerbate the condition, making the patient even more uncomfortable. “Some studies have indicated that Claritin does not have as much of an effect on tear production as some of its competitors. But the question is: How much? And is it tolerable? The answer is that most people do tolerate it well, unless it is a really severe case of dry eye. In those cases an alternative remedy should be sought. The lack of tear production should also be addressed by frequently administering artificial tears as a supplement. This also dilutes any proinflammatory agents that are floating around in the tear film,” explained Dr. Lemp.
The bottom line may be that all dry eye patients, regardless of other treatment they may be on, should use artificial tears and lubricants as a protective measure and to reduce discomfort. Once the symptoms of dry eye are addressed, managing the symptoms of seasonal allergic conjunctivitis becomes more efficient and effective.
2 Bielory, L. et al. Med Gen Med 2007;9(3):35.