Allergy is undoubtedly one of the most common causes of conjunctivitis, and this is certainly true among the contact lens population. Patients often present with a constellation of non-specific symptoms, though itching is usually predominant. Associated symptoms include redness, swelling, tearing and occasional discharge.
Clinicians must be astute as some of these same symptoms can occur with contact lens related marginally dry eye. Patient history can be critical as many allergic conjunctivitis patients report associated systemic environmental allergies. In addition, baseline prefit contact lens evaluation may reveal tarsal follicles in those at risk for allergic conjunctivitis.
A variety of antigens have been implicated in allergic conjunctivitis, with seasonal pollens, animal danders, and dusts most commonly implicated.
In the contact lens wearing population the aforementioned antigens may be responsible, though denatured tear constituents or solution preservatives may adhere to the lens surface and initiate an allergic response.
As is true of many contact lens related problems, allergic conjunctivitis is most effectively treated with lens discontinuation (figure 6). Patient symptoms are ameliorated with cool compresses, ocular irrigation, and topical antihistamines / decongestants. Rarely, topical steroids are warranted. Topical non-steroidal anti-inflammatory agents can benefit the allergic conjunctivitis patient by virtue of their prostaglandin inhibition. However, as they exert their therapeutic influence on the cyclo-oxygenase pathway they do not influence leukotriene synthesis. In more severe allergic presentations topical steroids are acceptable, though this is rarely necessary. Oral therapeusis is often beneficial as an adjunct in more symptomatic cases of allergic conjunctivitis. In particular, Benadryl can assist with acute bulbar chemosis while agents such as Seldane, Hismanal, and Claritin are effective in chronic prophylaxis. It is important to review the patient's drug history before recommending OTC or prescription antihistamines. Drug interactions or allergic responses can compound the initial problem. The dosage should be titrated so as to maximize the therapeutic response with the least amount of medication. Generally, allergic conjunctivitis patients experience significant improvement within 72 hours of initiating treatment.
Contact lens management of the allergic conjunctivitis patient can be as vexing as that of the contact dermatitis patient, due mainly to the multitude of potential antigens. Two main strategies should prevail in refitting the allergic conjunctivitis patient - alter the lens care regimen and minimize lens spoilage. The first goal is achieved by changing the patient's lens care, preferably to a preservative free system. The second objective can be met by placing the patient in a disposable or frequent replacement contact lens. If the patient is currently wearing a disposable lens, changing to a different class of disposable lens (from group IV to group II or group I) is indicated. If recurrent allergic conjunctivitis occurs despite your best efforts, refitting the patient into a gas permeable contact lens may suffice.
In the differential diagnosis of contact lens allergic conjunctivitis one must always remember that this condition can prevail in the absence of contact lens wear. Non-lens related allergic conjunctivitis should be optimally controlled prior to resuming lens wear.