The “itch” in itchy eyes, also called ocular pruritus, may be centered in the eyeball itself or the eyelids. While itchy eyes are often suggestive of allergies, there are many different issues that can make your eyes feel itchy. It’s essential to understand the root cause before you can find an appropriate treatment to relieve your eyes. Here’s a look at some common causes of itchy eyes.
Allergies cause itchy eyes in much the same way they cause a runny nose. For people with allergies, coming into contact with certain substances that are generally harmless incites the immune system to mark those substances as “dangerous”. Future contact creates an immune system reaction that prompts the production of histamine. Sometimes, coming into contact with these allergens, such as pet dander, mold, dust, or pollen occurs through the eye. Rather than creating a lot of mucus, this histamine production instead makes the eyes itchy, red, and watery.
Sjogren’s syndrome is a chronic immune system disease. The glands in the eye that produce moisture are affected, creating one of the first and most common symptoms -- dry eye. Eventually, the disease will damage other parts of the body. Sjogren’s appears to be caused by a genetic predisposition that can be triggered by infection.
Dry eye can also occur in other ways and is a common cause of itchy eyes. Dry eyes are the result of inadequate tears and other lubrication provided by eye glands to keep the eyes healthy and free of pathogens. Aging, certain diseases, medications, surgeries, and damage to the tear ducts can all inhibit tear production. Conversely, dry eye can be caused because the moisture that is produced evaporates too quickly. This can be the result of air conditions, not blinking enough, or issues with the eyelids. Another cause of dry eye is the result of your tears being incorrectly composed. Made of oil, water, and mucus, if anything goes wrong with any aspect of tears, it can result in dry eye.
Itchy eyes can also be the result of certain infections. Keratitis and conjunctivitis (pink eye) are both eye short term eye diseases that can develop because of pathogens or other reasons. Noninfectious keratitis can develop because of trauma to the eye. While it may occur simply because of a scratch or injury, trauma can also make it easier for infectious keratitis to develop, allowing an easier pathway for pathogens to enter. Infectious keratitis can be viral (herpes zoster, herpes simplex, and chlamydia viruses), or the result of wearing contact lenses contaminated with bacteria or parasites like acanthamoeba. Just swimming in contaminated water can cause keratitis if you have previously damaged cornea.
Conjunctivitis may be caused by bacteria or viruses; this form is quite contagious and often accompanied by a mucous-y discharge and cold symptoms. Allergic conjunctivitis appears in a similar fashion to itchy eye caused by allergies -- an allergen gets into the eye, triggering histamines. Itchy eyes in this case are often accompanied by general allergy symptoms. Foreign objects and chemical burns can also cause conjunctivitis; additional symptoms may include irritation, redness, excessive tearing, and discharge.
Ocular rosacea generally occurs in individuals also affected by rosacea, a chronic red rash that develops on the face. Although the exact cause isn’t understood, scientists believe heredity and environmental factors play a role. Other things that may impact the appearance of ocular rosacea include eyelash mites, blocked glands, and bacteria. Ocular rosacea may be triggered by spicy food, extreme temperatures, stress and other strong emotions, and some medication.