context: Conjunctivitis is one of the most common and treatable eye conditions in children and adults. Often called "pink eye," it is an inflammation of the conjunctiva, the tissue that lines the inside of the eyelid and the white of the eyeball, and helps keep the eyelid and eyeball moist. Viruses, bacteria, irritating substances (shampoo, dirt, smoke, pool chlorine), sexually transmitted diseases ( STDs), or allergens (substances that cause allergies) can all cause conjunctivitis. Pink eye caused by bacteria, viruses, or STDs can spread easily from person to person, but it is not a serious health risk if diagnosed promptly; allergic conjunctivitis is not contagious. It is important to find out whether your pink eye is caused by allergies or infection, because each condition has different treatments. This article focuses on allergic conjunctivitis. Symptoms of allergic pink eye include: Redness in the white of the eye or inner eyelid Increased amount of tears Itchy eyes Blurred vision Swelling of the eyelid In allergic conjunctivitis, these symptoms are usually present in both eyes (not always equally). See your ophthalmologist (a doctor and surgeon who is trained to treat eye conditions), optometrist (doctor trained to treat eye conditions), or family doctor if you have any of these persistent symptoms. Allergy-associated pink eye may disappear completely, either when the allergy is treated with antihistamines, or when the allergen is removed. So, the first line of treatment is allergen removal. This may include things like wearing a hat outside and washing your face frequently during allergy season. Your doctor also may recommend you use one or more of the following: Ocular (topical) decongestants: These medicines reduce redness by constricting small blood vessels in the eye. They are not recommended for long-term use. Using these drops for more than a few days can actually worsen symptoms. Ocular (topical) antihistamines: These medicines reduce redness, swelling, and itching by blocking the actions of histamine, the chemical that causes these symptoms of allergy. They are available both over-the-counter and by prescription. Ocular (topical) lubricants: People with allergic conjunctivitis often don't produce enough tears which make symptoms worse. Lubricant drops can be used hourly if needed. Ocular (topical) steroids: When other medicines fail, your doctor may prescribe steroid eye drops to relieve the symptoms of conjunctivitis. These must be used with the supervision of your doctor, because they can cause elevated pressure inside of the eye, which can lead to vision damage. Your doctor also must check for viral eye infections, such as herpes, before ocular steroids are used. These drops can also increase the risk of cataracts, clouding of the lens of the eye that can impair vision. Ocular (topical) mast cell stabilizers (such as Cromolyn): This medicine works by preventing specialized cells from releasing histamine. It works best when started before symptoms occur. Systemic (oral) versions of the above medications: These are used for severe cases. Immunotherapy : Allergy shots can be effective for treating pink eye caused by allergies. Oral tablets containing the same extracts as shots are also available. To relieve symptoms of allergic pink eye: Remove contact lenses, if you wear them. Place cold compresses on your eyes. Try nonprescription "artificial tears," a type of eye drop that may help relieve itching and burning (note: Other types of eye drops may irritate the eyes and should not be used). Do not use the same bottle of drops in the other eye if it is not affected. The best defense against allergic pink eye is a good offense: Try to avoid substances that trigger your allergies. An allergy specialist can test to determine what your specific triggers might be. Don't touch or rub the affected eye(s). Wash your hands often with soap and warm water. Wash your bed linens, pillowcases, and towels in hot water and detergent to reduce allergens. Avoid wearing eye makeup. Don't share eye makeup with anyone else. Never wear another person's contact lens. Wear glasses instead of contact lenses to reduce irritation. Wash your hands before applying the eye drops or ointment to your eye or your child's eye. Do not use eye drops that were used in an infected eye in a non-infected eye.