Eye allergies are one of the most common reason that people visit the eye doctor. Studies estimate that ocular allergies affect 15 to 40% of the population. The characteristic symptoms include itchy, red, watery and swollen eyes. Upper respiratory symptoms such as a runny nose, sneezing and coughing may accompany the ocular symptoms. The two main types of allergies are seasonal and perennial.Eye allergies are on
The yellow pollen dust that starts to cover everything in late February on Merritt Island signals the coming of spring and seasonal allergies. The ubiquitous fairy-dust like pollen that coats even garage-kept cars is pine pollen. Other major tree pollen contributors include oak, cypress and juniper trees. Tree pollen allergy season typically runs from February to April. Grass pollen allergies take off in April and goes through October and ragweed allergies occur from August to November. These are all considered seasonal allergies. Perennial allergies include mold, dust mites and animal dander. These irritants are present year round.
An allergy is an inappropriately exaggerated immune response to a relatively harmless substance. When an allergen, such as pollen, lands on the surface of the eye it is attacked by an immune cell. The immune cell will make an antibody to fight the allergen. If the antibody encounters the allergen again it will activate a cell called a mast cell which start the allergy cascade by sending out a blast of chemicals including the famous histamine. These chemicals are what will produce the itchy, red eyes. Although the medical community understands the process of the allergic response fairly well it is still a mystery as to why only some people have allergies, why childhood allergies can disappear and why some people develop allergies later in life.
There are several available treatment options for people that are affected by ocular allergies. As a first step, I may start my patients on preservative-free artificial tears. Patients that have dry eyes have a higher incidence of ocular allergies due to the fact that there are not enough quality tears to wash the irritant out of the eyes. Artificial tears dilute the concentration of the allergen in the eye. Oral anti-histamine pills may help ocular allergy symptoms in some people but studies have shown that anti-histamine pills do not reach the eye in concentrations comparable to that achieved with eye drop medications. You must also be aware that antihistamine pills can have a drying effect on the eye and indirectly worsen symptoms. Over-the-counter allergy drops provide relief from symptoms by blocking the histamines released by the mast cell. However, they do not have any effect on the other chemicals released. The most common medication that I prescribe for my allergy patients are the newest prescription allergy drops which are both anti-histamines and mast cell stabilizers. These medications block histamines which provides immediate relief but they also work by stabilizing the mast cell. By targeting the mast cell these medications prevent more of the allergy symptoms and provide a longer lasting effect. Steroid eye drops can be used for a short period of time to get effective control of severe cases. I often will begin my patients with the worse symptoms on a steroid eye drop to get effective control of severe cases and then taper them to anti-histamine/mast cell stabilizers. Effective management of allergic eye disease can reduce the symptoms and greatly improve quality of life.