Allergic conjunctivitis frequently accompanies seasonal allergy symptoms, specifically known allergy exposures or a history of atopy. As such, recurrent episodes are commonly seen. Practitioners should elicit a personal history of allergies and atopy, as well as, a history of similar episodes in the past. Practitioners should ask about specific symptoms from the current and any past episodes. Itchiness and diffuse bulbar and tarsal conjunctival injection are the most commonly reported symptoms and are present in all subtypes of allergic conjunctivitis. Other histories and physical exam findings vary with the specific subtype of allergic conjunctivitis.

Simple Allergic Conjunctivitis: Clear, watery discharge is the most commonly seen discharge and is usually bilateral with minimal crusting in the mornings. Pain and decreased visual acuity are not commonly reported in simple allergic conjunctivitis and should prompt the provider to consider another diagnosis. Eyelid edema and chemosis are not uncommon and can be quite marked.

Vernal Keratoconjunctivitis: Symptoms are usually most severe in the spring and include thick mucus discharge, pain, photophobia, and blurred vision. Patients will also often complain of foreign body sensation. On examination, corneal ulcers and conjunctival infiltrates can sometimes be found. Giant papillae on the tarsal conjunctiva are universally seen on examination.

Atopic Keratoconjunctivitis: Symptoms are usually perennial and include pain, blurry vision, photophobia, and foreign body sensation. Examination reveals findings similar to simple allergic conjunctivitis with the addition of chronic inflammatory changes to the ocular surface (corneal scarring and neovascularization) and varied changes to the eyelids (lower lid more commonly) and peri-orbital skin that range from mild atopy to lichenification.

Giant Papillary Conjunctivitis: Symptoms consistent with simple allergic conjunctivitis often give way to worsening itch and discharge that becomes thick mucus instead of clear and watery. Patients usually report worsening pain and blurry vision with the increased sense of foreign body (contact lenses, sutures). The examination reveals findings consistent with simple allergic conjunctivitis as well as giant papillae covering the tarsal conjunctiva.

The diagnosis is made clinically with a thorough history and classic physical examination findings. If there is any concern based on the history and physical examination, fluorescein staining of the cornea can be used to ensure that there is no corneal abrasion. Laboratory testing is generally not needed, although skin prick or serum allergy testing can be helpful for mitigating the disease process by identifying the offending allergens so that they can be avoided if possible.[3][9]

Simple allergic conjunctivitis: All patients should be educated about general allergic eye care. They should be discouraged from rubbing their eyes which causes mast cell degranulation and worsening of symptoms. They should be asked to apply artificial tears and cool compresses frequently. If possible, they need to avoid known allergen exposures and remove contact lenses (if applicable). Mild acute forms can be treated with over the counter antihistamines, or antihistamine and vasoconstrictor combination drops for relatively short periods. The patient should be warned against mild rebound conjunctival injection if they use a drop with a vasoconstrictor. Seasonal and perennial allergic conjunctivitis should be given combination antihistamine and mast cell stabilizing drops. Topical nonsteroidal anti-inflammatory drops are more effective than placebo but far less so than antihistamine/mast cell stabilizing drops. For refractory cases, corticosteroid drops can be used in short bursts (less than two weeks) in conjunction with a specialist consultation and follow-up. Systemic antihistamines and steroids also have a limited role in refractory cases and in cases where the patient has systemic, as opposed to isolated ocular, symptoms.[10][11][12]

Vernal and Atopic Keratoconjunctivitis: Patients should be given the same education about general allergic eye care (avoid rubbing eyes, use artificial tears and cool compresses, avoid allergen exposure) as simple allergic conjunctivitis.  Initial pharmacotherapy is similar to seasonal and perennial allergic conjunctivitis with topical combination antihistamine/mast cell stabilizing drops. Refractory cases should be referred to a specialist who can prescribe topical corticosteroid. If the patient continues to be refractory or cannot be weaned from topical steroid therapy, topical or systemic calcineurin inhibitors can be used.

Giant Papillary Conjunctivitis: First item of management is to remove the mechanical irritant which is most commonly a contact lens. Patients should be educated and begin the same general allergic eye care used in other subtypes of ocular allergy (avoid rubbing eyes, use artificial tears and cool compresses, avoid allergen exposure). Initial pharmacotherapy is similar to other ocular allergies, for example, topical antihistamine or combination antihistamine and mast cell stabilizing drops. In conjunction with a specialist, topical corticosteroid drops are used in refractory cases (similar to vernal and atopic keratoconjunctivitis), but calcineurin inhibitors have no role in treatment.

• Viral conjunctivitis
• Bacterial conjunctivitis

In most patients, the prognosis is good. Complications are rare but recurrence of symptoms is not uncommon. For patients who sustain corneal damage, this may be associated with visual loss. The medications used to manage allergic conjunctivitis may sometimes also induce cataracts.

Prevention is the key and this means making changes in lifestyle. Today, many allergists can perform skin tests to identify the allergen, which allows one to make a long term preventive strategy 

The majority of patients with allergic conjunctivitis are first seen by the pharmacist, nurse practitioner or primary care provider. The patients may be in the pharmacy searching for an over the counter treatment; the pharmacist should take this opportunity to educate the patient on lifestyle changes and also refer the patient with serious/recurrent symptoms to an ophthalmologist.

Patients with allergic conjunctivitis need to avoid the offending antigen, and often this requires a change in lifestyle. Some patients may need to undergo allergy tests to determine the allergen and then make the behavior changes. Often the wearing of contact lenses may not be possible. In all cases, the patient should be educated on humidifying the home, wearing sunglasses when going out, avoiding mascara and makeup, using artificial tears liberally and applying cold compresses to the eye. [13][14][15]

While the primary care provider and nurse practitioner may see patients with allergic conjunctivitis as outpatients, they should always be alert for patients with visual changes or severe symptoms. Empirical prescription of topical steroids by the primary care providers is not recommended as these agents can also cause cataracts; referral to an ophthalmologist is prudent.

it is always possible that allergic conjunctivitis is mistaken for a much more serious disease. As a result, the nurse and pharmacists dealing directly with the patient need to be vigilant and report to the clinical team interprofessional leader, the ophthalmologist or optometrist, if the patient is not improving relatively quickly. The pharmacist and nurse should similarly provide patient education and inform them that close followup is necessary if improvement does not occur quickly. Development of pain is always a disconcerting symptom and should require the team to report to the team leader. An interprofessional approach that involves open communication and joint education will result in the best care. If the interprofessional team works together to identify potential treatment failures before they develop significant morbidity, potential poor outcomes can be avoided.

Outcomes

The long-term outcomes of PAC and SAC are good, but a significant number of people are left with eye discomfort and poor ocular cosmesis. Some individuals develop recurrences leading to conjunctivochalasis-which is secondary to ongoing limbal conjunctival chemosis. Other complications that can occur in VKC and AKC include corneal opacification and ulcer formation. Some patients may develop lid involvement leading to difficulty in wearing contact lenses. Overall, the management of allergic conjunctivitis also leads to time off work and an increased cost of care because of frequent visits to the eye specialist and the need to buy prescription eye drops. Finally, drugs used to manage allergic symptoms may also lead to adverse reactions like cataracts.[16][17] (Level V)