Do you have red, itchy, watery eyes and a runny nose? With the weather warming up and the plants blooming, it is allergy season again. The eyelids and surface of the eye are readily affected by allergies to ragweed, pollen, and mold. An allergic reaction occurs when the immune system recognizes a substance, or allergen, as “foreign.”
The skin of the white of the eye is a specialized tissue called the conjunctiva. Inflammation or irritation of the conjunctiva due to allergies is referred to as allergic conjunctivitis. The conjunctiva acts a barrier, just as the skin of the hand serves as a defense mechanism of the body. It therefore contains tear glands (mucin cells) and different types of immune cells, including allergen activated mast cells. Mast cells capture allergens on the conjunctival surface and release histamine into the adjacent tissue. Histamine is a molecule that activates nerve endings to generate an itch sensation and activates blood vessels to enlarge and release fluid leading to red and swollen tissue. The diagnosis of allergic conjunctivitis is made based upon patient history, symptoms and examination findings.
The best treatment for allergies is to reduce or eliminate exposure to the offending allergen(s). Wearing sunglasses outside not only protects against UV light exposure, but blocks allergen contact to the eye. Over-the-counter artificial tears or decongestant (i.e., Naphcon-A) drops flush the allergens away from the ocular surface. The latter also can constrict blood vessels to temporarily take away redness. Cold compresses can also relieve itching and puffiness. The mainstay of the ocular allergies are topical anti-histamine drops (Alway, Elestat, Optivar, Pataday, Zaditor, for example), which are available either over-the-counter or by prescription. These block the release of histamine and its activity on nerve endings and blood vessels. Usually local application of drops is more effective for allergic conjunctivitis than oral anti-histamine use. Patients with severe allergies may need stronger allergy drops, such as steroids. However, steroids should be prescribed cautiously as their prolonged use increases the risk for cataracts and glaucoma in some patients. Also, an evaluation by an allergist may be helpful to identify which offending agents to avoid. It is generally not a good idea to wear contacts when ocular allergies are active.
An examination by your eye doctor can differentiate allergic conjunctivitis from other common conditions that cause eye redness or “pink” eye, including viral or bacterial infections, contact lens over-wear, and dry eye syndrome.