What Is Allergic Conjunctivitis? Symptoms, Causes, and Treatment

Medically Reviewed By Elizabeth Feuille, MD
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Red, watery, itchy eyes? If these symptoms occur in the presence of allergens like pollen or pet dander, you may have allergic conjunctivitis. You can treat allergic conjunctivitis by avoiding the allergen. You can also treat it with basic eye care and medications — eye drops, pills, and immunotherapy. The conjunctiva is the protective membrane that covers the whites of your eyes and inside of the eyelids. If something you are allergic to comes in contact with the conjunctiva, you can develop allergic conjunctivitis. A common term for it is eye allergy. Your immune system overreacts to the allergen, resulting in local irritation and inflammation.

You may notice that your symptoms reappear during certain seasons — when outdoor allergens can be high — or after visiting particular places.

This article discusses the types of allergic conjunctivitis, symptoms and causes, prevention tips, and treatment options. 

What is allergic conjunctivitis? 

Young child petting cat outdoors
Jessica Klaus/Stocksy United

Allergic conjunctivitis is a common inflammatory eye condition that occurs when allergens come in contact with your eyes. About 40% of people experience allergic conjunctivitis.

Some people refer to allergic conjunctivitis as pink eye. Unlike some other forms of pink eye, allergic conjunctivitis is not an eye infection nor is it contagious

Allergic conjunctivitis most often involves both eyes, but one may experience stronger symptoms than the other.

What are the symptoms of allergic conjunctivitis? 

Symptoms of allergic conjunctivitis include:

  • eye redness
  • itchy eyes, a symptom which is almost always present
  • eye burning sensation
  • gritty sensation under the eyelid
  • watery discharge
  • swollen eyelids
  • mildly blurry vision

The American Academy of Ophthalmology describes three types of allergic conjunctivitis.

Acute allergic conjunctivitis

This type of allergic conjunctivitis comes on suddenly. Symptoms usually go away hours after you are no longer near the allergen, such as pet dander or dust. These symptoms sometimes occur alongside other allergy symptoms, such as eczema, a stuffy nose, and an itchy throat.

Seasonal allergic conjunctivitis

Seasonal allergies can cause repeated bouts of acute allergic conjunctivitis. You may notice your symptoms increase anytime you go outside or only when pollen counts are high. How your symptoms are triggered depends on the severity of your allergy. 

Find out what allergists say about seasonal allergies here.

Perennial allergic conjunctivitis 

This is allergic conjunctivitis throughout the year. If you have eye allergies year-round, you may be allergic to something indoors, such as dust mites or mold.

What causes allergic conjunctivitis?

Anything you are allergic to that makes contact with the conjunctiva can cause allergic conjunctivitis. With eye allergies, the allergen is typically an airborne one.

Allergies vary between people. However, common airborne allergens include dust mites, pollen, pet dander, and mold.

Skin prick tests can help determine what type of allergen is causing allergic conjunctivitis.

Learn more about allergy tests here.

How can you prevent allergic conjunctivitis? 

Once you understand what allergens are causing your allergic conjunctivitis, you can take steps to avoid coming in contact with them. Your doctor may suggest the following prevention tips depending on your case: 

  • Avoid opening windows or going outside when the pollen or mold count is high. 
  • Install screens on your windows for when you do open them. 
  • Wash your hands and body and avoid touching your eyes after being outside or near animals. 
  • Wash your bedding weekly.
  • Use a high-energy particulate (HEPA) air filter in your home. 
  • Keep the humidity levels at 35–50% in your home. 
  • Avoid letting your pets into the areas of your home where you spend the most time. 
  • Remove carpets from your home if possible. 

How do you diagnose allergic conjunctivitis? 

Your healthcare professional may suspect allergic conjunctivitis based on your symptoms and health history. They will examine your eye, eyelids, and surrounding tissues.

To confirm a diagnosis of allergic conjunctivitis, your doctor should first rule out other types of conjunctivitis. Other types of conjunctivitis include viral or bacterial conjunctivitis, which result from infection. These forms are contagious and involve different treatment plans. 

Since redness and swelling occur in all types of conjunctivitis cases, it may be difficult to confirm a diagnosis, explains the Centers for Disease Control and Prevention (CDC). Your doctor may use a cotton swab to get a fluid sample from your eyelid to test for a virus or bacteria in a lab.

Doctors differentiate the types of conjunctivitis in the following ways:

  • Viral conjunctivitis: In this condition, a common cold or respiratory tract infection occurs alongside conjunctivitis and the eye discharge is watery.
  • Bacterial conjunctivitis: In this condition, the eye discharge is thick.
  • Allergic conjunctivitis: In this condition, the eyes are extremely itchy, and symptoms occur alongside asthma or hay fever.

How do you get rid of allergic conjunctivitis? 

Your doctor may suggest the following treatments for allergic conjunctivitis: 

  • antihistamine eye drops or pills, to stop allergic reactions from occurring
  • artificial tears or a saline solution, to rinse the allergen from the eyes 
  • cold compresses, to alleviate itching and swelling
  • corticosteroids, by prescription only and when other therapies are not effective

Contact your doctor if you are receiving treatment for allergic conjunctivitis and still have symptoms.

Other frequently asked questions

Below are other questions that people have asked about allergic conjunctivitis.

Is allergic conjunctivitis contagious?

Allergic conjunctivitis is not contagious. 

How long does allergic conjunctivitis last?

Allergic conjunctivitis lasts as long as the allergen is present and in contact with the eye. It can take several hours for symptoms to subside after removing the allergen. You can remove the allergen by leaving the area or rinsing the eye.

What eye drops can you use for allergic conjunctivitis?

Your doctor may suggest saline eye drops and eye drops containing antihistamines. Stronger medications — both eye drops and oral medications — may be necessary sometimes.

Summary

Allergic conjunctivitis happens when something you are allergic to comes in contact with your eyes. The conjunctiva is the mucous membrane covering the whites of your eyes and inner eyelids. The subsequent allergic reaction causes eye redness, eyelid swelling, itchiness, and watery eyes. There are other causes of these symptoms, so contact an eye professional for an accurate diagnosis.

Your doctor may suggest at-home treatments, eye drops, or prescription steroids to alleviate allergic conjunctivitis. You may be able to reduce symptoms of allergic conjunctivitis by avoiding allergens. You may need to apply medicated eye drops or take oral medications daily if you experience severe, chronic, or frequent allergic conjunctivitis.  

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Medical Reviewer: Elizabeth Feuille, MD
Last Review Date: 2022 Jun 30
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