Like all allergies, ocular allergies occur when the immune system identifies an otherwise harmless substance as an allergen. This causes the immune system to overreact and produce antibodies called Immunoglobulin E (IgE). IgE travels throughout the body to cells causing chemicals to be released which in turn causes an allergic reaction. In the eye, this is called allergic conjunctivitis as the allergen irritates the conjunctiva: the thin, clear membrane covering the white of the eye and the inner portion of the eyelids. 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 can trigger a similar allergic response in the eyes, nose, and throat.
The symptoms of allergic conjunctivitis can be very annoying and bothersome, but pose little threat to eyesight, except temporary blurriness. Unlike a bacterial or viral conjunctivitis, generally known as ‘pink eye,’ allergic conjunctivitis is not contagious. Seasonal (SAC) and perennial (PAC) allergic conjunctivitis are the two most common forms of ocular allergy. Both are classified as type 1 or immediate hypersensitivity reaction: SAC typically involves an acute reaction to seasonal allergens, but may present as a chronic irritation in some patients, while PAC is typically a chronic condition caused by household allergens that are always present, but may present as an acute reaction in some situations. Seasonal pollens can also exacerbate PAC.
In the below images, you can see a visual of what a IgG antibody looks like and how it interacts with allergens (antigens). It is at this point when the allergen attaches, or binds, with the IgG antibody that your allergies start to show physical or visual symptoms that can lead to red, ichy eyes for starters. Read about additional symptoms below.
Approximately 20% of the population suffers from allergic conditions, most commonly environmental allergies. According to the American Academy of Allergy, Asthma, and Immunology (AAAAI), the most common causes of allergic conjunctivitis are seasonal allergens such as ragweed, mold spores, grass or tree pollen. People with allergic rhinitis, asthma, and eczema or hay fever can be even more sensitive to environmental allergen. Up to 80% of hay fever patients may have allergic eye conditions. However, some patients can suffer year-round if they are sensitive to things like dust mites, smoke, perfumes, or pet dander. Those symptoms resulting from outdoor allergens tend to be worse than indoor causes.
Usually symptoms affect both eyes. They can occur alone or in conjunction with allergic rhinitis and usually occur shortly after being exposed to the allergen.
- Eyelid swelling or puffiness around the eye
- Itchy eyes
- Watering or tearing
- Sandy, gritty feeling in the eye
- Sensitivity to light
- Burning of the eyes
Don’t think you have to live in bubble or find a new home for Fluffy yet. Most of the time, symptoms can be managed by a few simple changes in routine or lifestyle, as well as with over-the-counter or prescription strength medications. The first defense against allergy is very low-tech - hygiene. Rinsing away the allergen on and around the eyes and showering and changing clothes after exposure can often help allergy suffers make it through their worst seasons. Of course, avoidance can be very effective at decreasing symptoms if you know a particular trigger. Keeping windows closed during high pollen season and of course frequent hand washing is an easy way to minimize exposure. In addition, wearing a wide brim hat and/or sunglasses outdoors can help protect the eyes from airborne allergens. Similarly, anti-allergen covers on bedding, frequent hot washing of sheets and pillowcases, and proper ventilation or even use of a humidifier to control airborne dust in bedrooms and living spaces can work wonders in controlling symptoms.
Non-prescription medication is the second line of defense against ocular allergies. Over-the-counter oral antihistamine pills and topical antihistamine eye drops often provide needed relief that is easy and cost effective for short-term treatment. Often people wait until the allergy response is more severe to take allergy medication, but most allergy medications work best when taken just prior to being exposed to the allergen. For mild symptoms frequent use of artificial tears can dilute the allergen and mediators enough that other pharmacological treatments are unnecessary. Some of the artificial tears that we frequently recommend include Blink, Systane Complete, Refresh, and Theratears. If we deem that a medication might be helpful to a patient, we sometimes start with an over-the-counter antihistamine eyedrop such as Alcon’s Zaditor or Bausch and Lomb’s Alaway, both of which use ketotifen fumarate ophthalmic solution as the active ingredient which can combat ocular itching and irritation.
If symptoms are chronic or more severe, stronger prescription medications such as corticosteroids or immunotherapy may be necessary. Continuous monitoring of the condition while on these medications may be necessary because of an increased risk of certain side effects. There are several classes of drugs at our disposal to treat ocular allergy symptoms. These are:
- Mast-cell stabilizers
- Combination mast-cell stabilizers/antihistamines
- Topical steroids
Mast-cell stabilizers prevent the release of histamine and inhibit eosinophil migration into tissue. This is what causes the allergic response. Eosinophils are a fancy term for a special white blood cell that fights allergic disease and certain infections. These types of medications typically do not provide immediate relief and work best if taken prior to exposure to an allergen. Some of the more common drugs in this class are Alamast, Crolim, Alomide, and Alocril.
Combination mast-cell stabilizers/antihistamines combine medications for a dual mechanism of action in one drop. They provide almost immediate relief from itching through their antihistaminic activity and provide longer-term protection by reducing the release of mast-cells, eosinophils and other cells - also known as mast-cell degranulation. Optivar and Elestat are popular choices for this class of medications. Newer drugs available include Bepreve (bepotastine besilate 1.5%, Ista Pharmaceuticals) which is a highly specific drug which blocks the receptors in the body that respond to histamine. Pataday (olopatadine hydrochloride 0.2%, Alcon) has a higher concentration of olopatadine than Patanol and is approved for once a day dosing. The recently launched Lastacaft (alcaftadine ophthalmic solution 0.25%, Allergan) also offers a once-a-day dosing regimen.
Topical steroids are ideal for the immediate relief of symptoms. Topical steroids have potent anti-inflammatory actions and also suppress the immune response. These drugs are typically dosed four times per day, so wear contact lenses while on treatment may be tedious as they must be removed prior to installation. If a topical steroid is prescribed for a twice daily dosage, be sure to wait 10-15 minutes before contact lenses are reinserted. Alrex and Lotemax are examples of these drugs.
Immunotherapy can be in the form of allergy shots or tablets. These are usually prescribed by an allergist and are designed to help desensitize your body to the offending allergen by building up an immunity to specific triggers. Although this desensitization process is not completely understood, suppression of allergen-specific IgE production is thought to play an important role. Multiple immunotherapy trials are under way or recently completed in the United States
Most rashes produced by cosmetics and makeup are irritations and not ocular allergies. An eye care professional can distinguish an allergic reaction from a simple irritation. Other skin problems such as rosacea, atopic dermatitis, and seborrheic dermatitis can go hand in hand with eye allergy symptoms. The rash produced by such a reaction often appears as a scaling, dry, itchy, red area, usually confined to the area where the cosmetic was applied. An example would be a reaction around the eyes with a new mascara or a full facial rash due to application of a lotion or moisturizer. Sometimes the reaction may occur soon after applying the offending agent and sometimes it may occur 1-2 days later. A full range of symptoms can occur including redness, stinging, burning, hives, welts, and itching. Less commonly, we see blackheads, follicules, or darkened skin. Keep in mind, any ingredient can cause a reaction, but certain ingredients are more likely to cause problems. Examples include parabens, alcohols, fragrances, lanolin, and quanternium-15 (a preservative).
Milder reactions will usually resolve with no treatment and simply avoiding the offending trigger. If treatment is necessary, some reactions with respond to a 1% hydrocortisone cream that is available over-the-counter. Stronger topical steroids can also be prescribed by a healthcare provider.
To make this area of concern even more confusing is the fact that cosmetics and makeups are not regulated by the US Food and Drug Administration (FDA). The use of hypoallergenic, natural, and pure are used simply as marketing tools and have little to do with consumer safety. Per the FDA website: “FDA does not have the legal authority to approve cosmetic products and ingredients (other than color additives) before they go on the market. We also do not have a list of tests required for any particular cosmetic product or ingredient. However, a manufacturer or distributor of a cosmetic is legally responsible for ensuring that a marketed product is safe when consumers use it according to the directions in the labeling or in the customary or expected way. FDA can take action against the manufacturer of a cosmetic on the market if we have reliable information to show that a cosmetic does not meet the legal requirement for safety."