Eye Allergies

An allergic reaction that affects the conjunctiva, a clear layer of the mucous membrane overlying the eyes, is referred to as allergic conjunctivitis.

Why do I have eye allergies?

Approximately 20% of the population suffers from allergic conditions, the most common environmental allergies. Allergic reactions to environmental agents that involve the eyes are common. An allergic reaction that affects the conjunctiva, a clear layer of the mucous membrane overlying the eyes, is referred to as allergic conjunctivitis.

Allergic conjunctivitis is divided into several major subtypes, with the most common subtypes being seasonal allergic conjunctivitis (SAC) and perennial allergic conjunctivitis (PAC). SAC and PAC are triggered by an immune reaction involving a sensitized individual and an allergen. Simply stated, this means that if someone is allergic to a particular substance, such as pollen, and then is exposed to it, this triggers an allergic reaction.

What are the symptoms of eye allergies?

In the eyes, the allergic reaction causes itchy eyes, watery eyes, red eyes, and/or swollen eyes.

Ocular (eye) allergies often affect the conjunctiva, a clear layer of mucous membrane overlying the eyes. This clear layer of mucous membrane is the same type of mucous membrane that lines the inside surface of the nose. As these two areas are so similar, the same allergens (substances that induce an allergic reaction) can trigger the same allergic response in both areas.

Common allergens include the following:

• Trees
• Grasses
• Weeds
• Dust mites
• Pets (especially cats and dogs)
• Molds

The main difference between SAC and PAC is the timing of the symptoms.

• In an individual with SAC, symptoms are generally limited to a defined period of time.
  • Typically, tree pollen causes symptoms in the spring, grasses cause symptoms in the summer, and weeds trigger symptoms in late summer and fall time until the first hard frost.
  • Symptoms generally resolve during other times of the year, particularly during the wintertime.
• In an individual with PAC, symptoms are generally present throughout the year.
  • Instead of being triggered by outdoor allergens, symptoms are triggered by indoor allergens, such as dust mites, pets, mold, and even cockroaches, particularly in urban areas.
  • Individuals with PAC may still experience a seasonal worsening of symptoms if they are also sensitized to outdoor allergens in addition to their indoor allergens.

Itching is the most common symptom of any allergic reaction, and this is also true for allergic conjunctivitis. In addition to ocular itching, the following eye allergy symptoms and signs are also commonly reported:

• Redness
• Tearing
• Burning sensation
• Mattering and/or mucous production
• Mild swelling around the eyes
• Importantly, symptoms of pain, blurred vision, double vision, or changes in vision are not typical for allergic conjunctivitis and warrant prompt medical attention.

Although allergies often improve with avoidance of the allergen, this is often not practically feasible. If symptoms of allergic conjunctivitis are adversely affecting the quality of life, seeking care from an allergist or ophthalmologist (a medical doctor specializing in eye care and surgery) may help provide symptomatic relief. There are a host of options to help manage symptoms, including environmental control measures, medical therapy, and allergen immunotherapy.

If an individual is experiencing any changes in vision, such as blurred vision, floaters, or double vision, this warrants prompt medical evaluation, typically with an ophthalmologist.

Most often, a medical professional is able to diagnose allergic conjunctivitis from the symptoms alone. Testing is rarely necessary. In certain cases, an ophthalmologist may perform the following test to rule out other conditions:

• The front of the eyes is examined using a special microscope, called a slit lamp. Using the slit lamp, an ophthalmologist checks the eyes for dilated blood vessels, conjunctival swelling, and eyelid swelling, all of which are indicative of an allergic reaction.
• Rarely, scraping of the conjunctiva is performed to check for eosinophils. Eosinophils are certain white blood cells that are commonly associated with allergies.
• An allergist may perform testing to identify an environmental trigger for eye symptoms. Testing generally involves skin prick testing for a standard panel of airborne allergens. The allergist may also order blood work looking for allergic antibodies for various allergens (in vitro IgE testing).

• Is there a specific, identifiable cause?
• How can symptoms be controlled?

Numerous over-the-counter medications, such as allergy eyedrops, oral antihistamines, and nasal corticosteroids can be used as directed for ocular allergies. Some commonly used options are as follows:

• Eyedrops
  • Ketotifen (Zaditor)
• Oral antihistamines
  • Loratadine (Claritin)
  • Cetirizine (Zyrtec)
  • Fexofenadine (Allegra)
  • Diphenhydramine (Benadryl)
• Nasal steroids
  • Triamcinolone (Nasacort)
  • Fluticasone (Flonase)

In addition, many prescription medications are also available to help reduce allergies.

Eliminating or even minimizing exposure to allergens may lead to symptomatic improvement. Therefore, an evaluation with an allergist to identify culprit allergens may be very helpful. The following are some environmental control measures to minimize allergen exposure.

• For dust mites:
  • Decrease ambient humidity by using a dehumidifier.
  • Wash sheets in hot water once weekly.
  • Use allergen-impermeable covers for mattresses and pillows.
  • Minimize carpeting, linens, stuffed animals, etc., where dust mites can collect.
• For pets:
  • Keep pets out of the bedroom at all times.
  • Use HEPA filters.
  • Bathe the pets at least once weekly.
• For mold:
  • Decrease humidity with a dehumidifier.
  • Eliminate water leaks and standing water, particularly in basements.
• For outdoor pollens like trees, grasses, and weeds:
  • Use air conditioning and keep windows and doors closed.

Unfortunately, allergen avoidance is not always easy or possible. If this is the case, the following at-home remedies may provide an individual with some relief from ocular allergies.

• Apply cold compresses to the eyes to help reduce the allergic reaction.
• Use artificial tears/lubricating eye drops as needed to help flush out allergens that get into the eyes.
• Use over-the-counter medications, such as allergy eye drops, oral antihistamines, and/or nasal corticosteroids.

Prescription eyedrops are generally very effective and safe, since they are applied topically and have few if any systemic side effects. Most eyedrops can be used once to twice daily and help not only with relieving symptoms but can also prevent symptoms. Some common allergy eyedrops include

• nedocromil (Alocril),
• olopatadine (Patanol),
• azelastine (Optivar),
• pemirolast (Alamast), and
• epinastine (Elestat).

An ophthalmologist may prescribe cyclosporine A (Restasis). By helping to reduce the inflammatory and/or allergic reaction, cyclosporine A may help decrease the symptoms.

For more serious cases, topical ophthalmic corticosteroids can also be used. However, many of the older corticosteroids are associated with eye side effects with long-term use. The newer ophthalmic corticosteroids have a much lower risk of side effects. Some common topical ophthalmic corticosteroids are

• loteprednol 0.02% (Alrex),
• loteprednol 0.05% (Lotemax),
• prednisolone (AK-Pred),
• rimexolone (Vexol),
• medrysone (HMS), and
• fluorometholone (FML, FML Forte, FML Liquifilm).

Allergen immunotherapy (allergy shots) is also an excellent treatment option for allergic conjunctivitis. If this is appropriate, an individual is seen by an allergist and completes testing for common airborne allergens. Based on the results, an allergist can prescribe immunotherapy that can not only improve symptoms but may also help get rid of existing allergies and also prevent future environmental allergies. Although immunotherapy is effective and safe, there is a small risk of allergic reaction (approximately 0.1%).

Historically, immunotherapy requires frequent visits to the allergist for subcutaneous injections. As of 2014, the FDA has approved sublingual immunotherapy (allergy tablets) that can be administered at home for grass and ragweed allergy, so this may be an option for treatment depending on individual sensitivities There is less risk for an allergic reaction with this type of therapy compared to allergy shots.

Follow-up appointments are scheduled as needed.

• For mild cases of PAC and SAC, annual follow-up visits can be on an as-needed basis or annually.
• For more severe cases or for intermittent exacerbations of normally mild disease, more frequent visits with an allergist or ophthalmologist may be beneficial.

Unfortunately, other than avoidance of the allergen(s), PAC and SAC cannot be prevented.

Prognosis for individuals with SAC and PAC is excellent. Beyond symptoms adversely affecting quality of life, these individuals should live an otherwise normal life. There is no risk for long-term changes in vision.

If you suffer from SAC or PAC, various organizations, including those specializing in eye care and allergy and immunology, provide informational resources. These organizations can also help someone locate an ophthalmologist and/or an allergist in the area.

American Academy of Ophthalmology
655 Beach Street
Box 7424
San Francisco, CA 94120
415-561-8500

American College of Allergy, Asthma & Immunology
85 West Algonquin Road, Suite 550
Arlington Heights, IL 60005
847-427-1200

American Academy of Allergy, Asthma, and Immunology
555 East Wells Street, Suite 1100
Milwaukee, WI 53202
414-272-6071

American College of Allergy, Asthma & Immunology, How Do I Find an Allergist?