Eye allergies, also called allergic conjunctivitis, are quite common. They occur when the eyes react to something that irritates them (called an allergen). The eyes produce a substance called histamine to fight off the allergen. As a result, the eyelids and conjunctiva become red, swollen and itchy. The eyes can tear and burn. Unlike other kinds of conjunctivitis, eye allergies do not spread from person to person.
People who have eye allergies commonly have nasal allergies as well, with an itchy, stuffy nose and sneezing. It is usually a temporary condition associated with seasonal allergies.
You can get eye allergies from pet dander, dust, pollen, smoke, perfumes, or even foods. If you cannot avoid the cause, your allergies can be more severe. You can have significant burning and itching and even sensitivity to light.
What are symptoms of eye allergies?
The most common eye allergy symptoms include:
If accompanied by nasal allergies, you may also have a stuffy, itchy nose and sneezing. You can also have a headache, an itchy or sore throat or coughing.
What causes eye allergies?
An allergy is when the body’s immune system reacts to an allergen that is normally harmless. When an allergen comes in contact with your eye, certain cells within your eye (called mast cells) release histamine and other substances to fight off the allergen. This reaction causes your eyes to become red, itchy and watery.
Allergens in the air — both indoors and out — cause many eye allergies. These allergens include:
- pollen from grass, trees and ragweed
- pet dander (dead skin cells shed by cats, dogs or other animals)
Allergic reactions to perfume, cosmetics or drugs can also cause the eyes to have an allergic response. Some people may be allergic to the preservative chemicals in lubricating eye drops or prescribed eye drops. They should use preservative-free drops instead if possible.
Sometimes, the eyes can react to other allergens that don’t necessarily come in direct contact with the eye. These can include specific foods or insect bites or stings.
Some people inherit eye allergies from their parents. You’re more likely to have allergies if both of your parents have them than if only one does.
An ophthalmologist uses a slit-lamp—a microscope with a bright light—to get a closer look at the surface of a young woman's eyes.
To provide proper treatment, your ophthalmologist will check to see if you have an eye infection or allergic conjunctivitis. They can usually diagnose allergic conjunctivitis easily. They will use a slit-lamp microscope to check for signs of eye allergies, such as swollen blood vessels on the surface of the eye. They will talk to you about your medical history and your family’s history of allergies.
Your ophthalmologist may test for a specific type of white blood cell in your eye. They will do this if your allergies are bad or if it is not clear that you have allergic conjunctivitis. They will gently scrape a tiny area of the conjunctiva and test this tissue for those white blood cells.
How are eye allergies treated?
The key to treating eye allergies is to avoid or limit contact with the substance causing the problem. But you have to know what to avoid. If necessary, an allergist can perform a skin or blood test to help identify the specific allergen(s).
If you are allergic to pollen, avoid going outdoors as much as possible when pollen counts are highest. Pollen counts are usually highest in the mid-morning and early evening. Also, avoid being outdoors when wind blows pollens around. When you are outdoors, sunglasses or eyeglasses can help to prevent pollen from getting into your eyes.
Keep your windows closed and use air conditioning, both in your car and home. This will help lower your exposure to pollen and other irritants while you are inside. Don’t use window fans, as they draw the pollen and other allergens inside. Keep your air conditioning units clean so they won’t cycle allergens inside.
If mold is an allergy trigger for you, recognize that high humidity can cause molds to grow. Aim to keep the humidity level in your home around 30 to 50 percent. Clean high-humidity areas like basements, bathrooms and kitchens often. Consider using a dehumidifier in particularly humid or moist places such as a basement.
If dust at home brings on your allergic conjunctivitis, try to keep dust mites away from your skin. Pay special attention to your bedroom. Use allergen-reducing covers for your bedding and especially for your pillows. Wash your bedding frequently with hot water that is at least 130 degrees Fahrenheit.
When cleaning floors, use a damp mop or rag instead of a dry dust mop or broom to trap the allergens.
If pets are a source of allergies for you, try to keep animals outside of the house as much as possible. It is particularly important not to allow a pet into your bedroom so that you can sleep in an allergen-free room. Consider hardwood or tile floors instead of carpeting, which traps the pet dander. Always wash your hands after touching a pet, and wash clothing that you have worn around pets.
Finally, always avoid rubbing your eyes, which only irritates them more.
Treating eye allergies with eye drops and medicine
Artificial tear drops help relieve eye allergies temporarily by washing allergens from the eye. They also relieve dry, irritated eyes by adding moisture. You can use these drops, available without a prescription, up to six times a day. You may use them as often as you need to if they are preservative free.
Decongestants (with or without antihistamines)
Decongestants reduce redness in the eyes from allergies. They are available as over-the-counter eye drops. If the decongestant eye drops you choose include an antihistamine, they can relieve itchiness as well. You should not use these types of eye drops for more than two to three days. Longer-term use actually increases your irritating symptoms.
Oral antihistamines may be somewhat helpful in relieving itchy eyes. But they can make eyes dry and even worsen eye allergy symptoms.
Eye drops with both an antihistamine to relieve itchiness and a mast-cell stabilizer help prevent eye allergies. You use them once or twice a day to relieve itching, redness, tearing and burning. How often you use them depends on which eye drop you choose.
Steroid eye drops can help treat chronic and severe eye allergy symptoms such as itching, redness and swelling. They should never be used without medical supervision due to possible serious side effects.
If symptoms are not controlled by allergen avoidance, eye drops or medicine, immunotherapy (allergy shots) may be an option. With immunotherapy, you get shots containing tiny amounts of the allergen. The dose gradually increases over time to help your body become immune to the allergens.
Your doctor can tell you which treatments are best for you.