Allergic Conjunctivitis
What is allergic conjunctivitis?
Allergic conjunctivitis is an allergic reaction on the surface of the eyes. It is a very common condition that occurs when your eyes come in contact with allergy-causing substances (allergens). Pollen, cat dander, and smoke are examples of allergens.
How does it occur?
The allergens may be in the air, such as smoke or plant pollen. Or they might be on your hands and get into your eyes when you touch your eyes.
When your eyes are repeatedly exposed to allergens, the body reacts and produces antibodies. When allergens in the air contact antibodies on the eye, an allergic reaction begins. The eye releases chemicals, including one called histamine. These chemicals cause symptoms of allergic conjunctivitis.
What are the symptoms?
The symptoms are eyes that are:
- itchy
- watery
- red
- sometimes swollen.
Sometimes the skin around the eyes is red and scaly.
Both eyes are usually affected unless just one eye came into contact with the allergen, as might happen with poison ivy.
How is it diagnosed?
Your health care provider will ask about your symptoms and check your eyes. Your family medical history may also be helpful.
Your provider may test you for reactions to specific allergens if you have a severe case of conjunctivitis that does not respond to the usual treatment.
How is it treated?
The first choice for treatment is to avoid the allergy-causing substance(s).
Medication is another option. Some people need to take antihistamine tablets, especially if they have other allergy symptoms. If you have only eye symptoms, eye drops may be the only medication you need. Some relatively new types of eye allergy drops can be quite effective: one is an anti-inflammatory medication, one is an antihistamine, and one is a combination of the two. Certain drops require a prescription from your health care provider. Some people can use eye drops on an as-needed basis; for example, just before mowing the lawn. Others need to use the drops daily during allergy season to prevent more severe symptoms.
You can also put cool compresses on your eyes several times a day to help relieve the symptoms.
How long will the effects last?
The symptoms of allergic conjunctivitis will last as long as the allergen is around, whether it's spring pollen or cat dander in a carpet. If you started having allergic reactions when you were a child and have continued to have them as an adult, you will probably have them the rest of your life. Anybody, however, may develop an allergy, including allergic conjunctivitis, at any time in his or her life.
Sometimes an eye infection (bacterial conjunctivitis) develops in addition to allergic conjunctivitis. This may happen because bacteria got into your eyes when you scratched or rubbed them.
How can I help prevent allergic conjunctivitis?
Often there is no way to prevent allergic conjunctivitis. You can try to lessen your symptoms by limiting your exposure to allergens. For example, avoid going outside when pollen counts are highest or when the wind is blowing allergens through the air. Use air conditioning rather than opening windows. Avoid using attic fans.
If your symptoms are severe, you may need to see an allergist and have tests to see what you are allergic to. You may then need to have allergy shots for 12 to 24 months.
