Allergic conjunctivitis is swelling and redness of the membrane that lines the eye. It is caused by exposure to foreign matter. The affected part of the eye is called the conjunctiva. The conjunctiva is the mucous membrane layer that covers the white part of the eye.
Pollen is often the cause of the problem. Other vegetable proteins, animal proteins, dust and fungus spores can cause it, too. Sometimes the allergic reaction can happen within minutes. Other times the reaction can be delayed for hours or days. This problem seems to affect people who have other allergy problems. These include eczema, asthma, hay fever or hives.
Other common causes of allergic conjunctivitis are exposure to animal hair, such as cat hair, or feathers.
A less common form of allergic conjunctivitis comes from bacteria on the eyelid or skin. The cause is often the staphylococcus bacteria. This type of allergy may lead to styes, which are pimple-like infections of the glands in the eyelid. It may also cause chalazions, which are blockages of the oil glands in the eyelid. Long-term problems related to allergies in the eye rarely occur. However, if uncontrolled, the problem can spread to other parts of the eye, such as the cornea and the space between the cornea and the iris. This can cause inflammation of the iris, which is the colored part of the eye.
Usual symptoms include:
The condition can also spread to the eyelids. The eyelids, as well, may become red with thickening, dryness and scaling of the skin.
People often think they have allergic conjunctivitis because their eyes are red, itchy or watery. These are also symptoms of hay fever. In more complex cases, the doctor uses a microscope to find signs of an allergy. Tiny bumps on the white part of the eye indicate that an allergy is present. This distinguishes it from bacterial or viral conjunctivitis.
The problem can be prevented by avoiding the material that causes the allergic reaction. Medications or preservatives in eye drops or contact lens solutions might make some people more sensitive. Air filters and air conditioners can reduce dust and allergens in the air. Avoiding dust and animal hair is also important.
Usually there are no long-term effects when allergic conjunctivitis is managed properly.
This condition cannot be passed to others.
Using nonprescription antihistamine eye drops can help some symptoms. In more difficult cases, prescription medications can be used. These are nonsteroidal anti-inflammatory drops such as
Antihistamine eye drops should be used sparingly. The drops should be used no more than 4 times a day. If corticosteroid eye drops such as
Since this condition is related to exposure to allergens it is usually chronic, seasonal, and tends to recur. Therefore, at the sign of symptoms, treatment should be started again.
Most people are able to monitor their allergic conjunctivitis independently. If medications are used frequently, periodic checkups with a healthcare provider are advised.
Author:William Stevens, MD
Editor:Keefe, Sandy, RN, MSN
Reviewer:Sal Sandoval, MD