Allergic Conjunctivitis

How often have you heard someone complaining—once again—about suffering from conjunctivitis? This frequent, painful and trivialized disorder is unknown to most people. Yet, it represents 95% of all forms of eye allergies. A recent study in the United States indicated that more than 41 million bottles of over-the-counter antibiotic eye drops are sold every year.

Inflammation or infection?

Conjunctivitis can be frequent and significantly impact one’s quality of life. Nearly 60% of patients surveyed on the consequences of eye allergies in their lives mentioned being less productive at work and that their symptoms had a negative impact on their daily activities, as well as on their emotional state.

In fact, allergic conjunctivitis is an inflammation of the conjunctiva caused by allergens from the environment. Now, what does it really mean?

Seasonal or annual conjunctivitis?

Two different forms of allergic conjunctivitis are known today: seasonal or annual. Seasonal allergic conjunctivitis (SAC) stems from sensitization to tree (spring), grass (summer) and ragweed pollen (fall). Thus, conjunctivitis symptoms appear at certain specific periods of the year, hence the term “seasonal.” More than half of allergic conjunctivitis cases are seasonal.

By contrast, annual allergic conjunctivitis (AAC) is not seasonally triggered. Its symptoms occur year round. It can stem from a variety of factors, including sensitization to dust mites and/or animals. Clinically, it is characterized by itchy, red, puffy and watery eyes. Some patients also complain about a burning or tingling sensation or say that they feel as though there is sand in their eyes.

How is conjunctivitis diagnosed?

The diagnosis is often based on the clinical symptoms reported by patients and is at the discretion of the optometrist or the physician. Consulting a professional is important to confirm the diagnosis, assess the health condition of the eye and exclude some related issues such as blepharitis (eyelid eczema) and dry eye. Some allergy tests are indicated to find the cause of the allergic conjunctivitis and permit optimal management. In clinics, our professionals are trained to detect the disease. In addition to having their eyes examined yearly, patients should constantly watch for symptoms related to conjunctivitis.

What are the available treatments?

Many treatment options are available. Ocular antihistamines (Bepreve, Patanol, Pataday) act as histamine antagonists, blocking its effect on the eye. Histamine is produced by the cells at the eye-level following contact with an allergen. Ocular antihistamines take effect quickly. In other words, the unpleasant effects of the inflammation are offset soon enough so the patient can carry on his or her activities as normally as possible. However, those taken orally (Aerius, Réactine, Claritin) are less effective and are associated with more frequent side effects (dry mouth, drowsiness, etc.).

Mast cell stabilizers (Zaditor) are also available over-the-counter. They act to prevent the release of inflammatory mediators (like histamine) through the eye’s immune cells. To maximize effectiveness, these eye drops must be used two to four times a day.

Lastly, ocular corticosteroids, which can be found in pharmacies under the name Alrex, control eye inflammation. The anti-inflammatory properties of these drugs are related to their ability to inhibit the activation of multiple inflammatory cell types. However, one must be careful when using these drops. In fact, using them for an extended period without a follow-up from an optometrist or an ophthalmologist may lead to an increased risk of glaucoma or cataract, two eye diseases that can cause visual field narrowing.

In summary, the symptoms of an allergic conjunctivitis, whether seasonal or annual, are quite unpleasant and differ in intensity. Most people suffering from an AAC or a SAC can treat themselves before consulting an eyecare professional. The result is a partial relief of conjunctivitis’s persistent or severe signs and symptoms. Many treatment options exist and eye health professionals should be consulted to benefit from the best possible treatment. Remember, the best way to keep your eyes healthy is by book an appointment with an eyecare professional at least once a year.

Dr. Jean-Nicolas Boursiquot, MD, MSc, FRCPC
Allergologist, CHU (University Hospital), Québec City