context: Millions of Americans have allergies. Most of those millions have symptoms involving their eyes. A common eye allergy affects the clear layer of skin that covers the front of your eyes and the inside of your lids (called the conjunctiva). Your doctor may refer to it as allergic conjunctivitis. There are several different causes for this. But for the most part, if you're allergic to a particular substance and then come into contact with it, you have an allergic reaction like itching and sneezing. That layer of skin covering the front of your eyes? It's the same type of skin that lines the inside of your nose. Because these two areas are so similar, the same things can trigger allergic reactions in both places. Common triggers include: Pollen Grass Weeds Dust Pet dander If you have seasonal allergies, you generally have symptoms for a short time. You may be bothered in the spring by tree pollen, in the summer by grass pollen, or in the fall by weed pollen. The symptoms tend to clear up during other times of the year, especially in the winter. If you have "perennial allergies," your symptoms probably last all year. You're likely allergic to indoor things, like dust mites, cockroaches, and pet dander. Seasonal outdoor allergens may make things worse if you're sensitive to them, too. Seasonal and perennial allergies have identical symptoms and, almost always, itching lets you know you're having an allergic reaction. Along with itchy eyes, you may have: Redness Tearing Burning sensation Blurred vision Inflammation Runny nose Your symptoms should improve on their own if you know what you're allergic to and you can avoid it. But if you don't know what causes your allergy, skin testing by an allergist can help figure it out. If you still don't know or you can't avoid the cause, a doctor who specializes in eye care and surgery -- an ophthalmologist or optometrist -- may be able to help. If you have seasonal allergies, make an appointment with him prior to your allergic season. This will let you start treatment before your symptoms kick in. If you have perennial allergies, routine appointments may be helpful. Occasional flare-ups may mean you need to see him more often. It might also help to get a consultation with an allergist. Is there a specific cause of my eye allergy? How can I ease my symptoms? Your eye doctor may be able to diagnose your eye allergy based on the symptoms you've told him about. He'll check your eyes to rule out other problems. He'll examine the inner lining of the eye lids using a microscope called a slit lamp. He'll be looking for dilated blood vessels and swelling. In very rare cases, he may scrape that layer of skin that covers the front of your eyes to check for something called eosinophils. They're cells that are commonly linked to allergies but are only found in the most severe cases. Get off to a good start by avoiding whatever you're allergic to. You can also try these tips: Minimize clutter where allergens can collect. Limit pillows, bedding, draperies, and other linens, such as dust ruffles and canopies. Also, keep knick-knacks to a minimum, since they can collect dust. Go with as little carpeting as possible. The carpet can harbor dust mites. Clean regularly and thoroughly. That'll help limit dust and mold. Get rid of any water leaks and standing water. Both encourage mold growth. Use barriers and filters. Shield mattresses and pillows with covers that block allergens. Use allergen filters in both the furnace and the air conditioner in your home. Also, be sure to change them regularly. Keep outdoor allergens outdoors by keeping windows and doors closed. Unfortunately, it's not always easy or possible to avoid the things that trigger your allergies. If that's the case for you, these at-home treatments may give you some relief: Apply cool compresses to your eyes to ease the allergic reaction. Use artificial tears or lubricating eye drops. Use over-the-counter medications , like allergy eye drops and oral antihistamines for mild allergies. Try not to rub your eyes, since that can make your symptoms worse. Lots of over-the-counter meds, like allergy or antihistamine eye drops as well as antihistamines you take by mouth, can help against mild allergies. Follow the directions on the packages exactly. Prescription eye drops usually work well, and most don't have side effects. Many of them are taken twice a day, and can be used to prevent an allergic reaction. Some common ones include: Azelastine ( Optivar) Epinastine ( Elestat) Ketotifen ( Zaditor) Nedocromil ( Alocril) Olopatadine ( Patanol) Pemirolast ( Alamast) Steriods are generally used to obtain initial relief, particularly bad allergic response. Your doctor might prescribe corticosteroids if your allergies are severe. They come with a risk of side effects. Some common corticosteroids used for eye allergies are: Fluorometholone ( FML, FML Forte, FML Liquifilm) Loteprednol 0.02% ( Alrex) Loteprednol 0.05% ( Lotemax) Medrysone ( HMS) Prednisolone ( AK- Pred) Rimexolone ( Vexol) For mild cases of seasonal or perennial allergies, annual follow-up visits with your eye doctor are a good idea. You may need to go more often for a severe case.