Focus on preventing corneal complications

February 15, 2007
Nancy Groves

Las Vegas-Ocular allergies affect up to 40% of the pediatric population, and this high prevalence has ramifications beyond providing symptom relief, said Terry Kim, MD, during a continuing medical education symposium here at the annual meeting of the American Academy of Ophthalmology.

Las Vegas-Ocular allergies affect up to 40% of the pediatric population, and this high prevalence has ramifications beyond providing symptom relief, said Terry Kim, MD, during a continuing medical education symposium here at the annual meeting of the American Academy of Ophthalmology.

"It's very important that we try to prevent corneal complications that are associated with allergic conjunctivitis," said Dr. Kim, associate professor of ophthalmology, Duke University School of Medicine, Durham, NC. "All of us know that keratoconus patients have reported significantly higher levels of allergy, itching, and rubbing as teenagers and adults, and the itching and rubbing are relevant to the pathogenesis.

"Chronic eye-rubbing can lead to adverse consequences, and there is no question, particularly with this population, that dosing frequency, comfort, compliance, and safety are all very important factors to consider in the management of ocular allergies," Dr. Kim added.

Among the various forms of allergic conjunctivitis, those most commonly seen in the pediatric population include seasonal and perennial allergies. Vernal and atopic forms tend to be much more severe but less common, and giant papillary conjunctivitis also is less common among children, Dr. Kim said.

Seasonal and perennial allergic conjunctivitis are primarily caused by environmental triggers-notably grass pollens and dust mites, respectively-but a genetic predisposition is also thought to play a causative role. The hallmark of clinical signs and symptoms is ocular itching, along with redness, chemosis, tearing, watery discharge, and lid edema. Other findings typically include a family history of allergic conjunctivitis, a lack of eosinophils found in scrapings, a spike in tear histamine, and normal histaminase function. These features tend to be milder in perennial compared with seasonal allergic conjunctivitis.

Vernal keratoconjunctivitis (VKC) is one of the more severe forms of ocular allergy seen in children and is most predominant in males aged 3 to 20 years. Patients may exhibit increased levels of superficial mast cells, eosinophils, and lymphocytes and decreased levels of histaminase. Besides typical signs and symptoms such as redness and itching, patients with VKC may experience ptosis; ropy mucous discharge; photophobia; large, nonuniform cobblestone papillae; Trantas dots; and limbal nodules. Corneal neovascularization and shield ulcers also may occur. Itching is very prominent in these patients, however, Dr. Kim noted.

Atopic keratoconjunctivitis (AKC) tends to affect an older population than VKC, typically occurring in individuals aged 20 to 50 years. Clinical findings of AKC include elevated levels of eosinophils, T-helper lymphocytes, and mast cells.

"In addition to the itching, redness, and swelling, these patients are very prone to corneal neovascularization and scarring in addition to scarring of the eyelids and periocular skin," Dr. Kim said. "Also, from the chronic rubbing, we believe there's a strong association with keratoconus."

Multiple options for topical ocular allergy treatments are available, including antihistamine/vasoconstrictor combinations, antihistamines, mast cell stabilizers, dual-acting antihistamine and mast cell stabilizer combinations, corticosteroids, and cyclosporine (Restasis, Allergan).

"With respect to managing allergic conjunctivitis in children, we need to consider the use of oral antihistamines. We've definitely moved to the second generation of antihistamines that tend to be less sedating and impair psychomotor abilities to a lesser extent," Dr. Kim said. "But our mainstay of treatment of pediatric allergic conjunctivitis includes the regular use of topical antihistamine/mast cell stabilizer therapy and, in some populations, both" the oral and topical medications.

Immunotherapy-such as corticosteroids or leukotriene receptor antagonists-is an option, but it generally is reserved for patients whose conditions are unresponsive to conventional therapy or who are unable to take these medications, Dr. Kim said.

The recent arrival on the market of olopatadine, a safe and effective topical combination antihistamine-mast cell stabilizer with once-a-day dosing (Pataday, Alcon Laboratories) should improve compliance and help combat the signs and symptoms of ocular allergy in the pediatric population, he added.

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