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What is Pink Eye?

Conjunctivitis, also called pink eye, is an inflammation of the clear thin outer layer (conjunctiva) of the eyeball. When small blood vessels in the conjunctiva become inflamed, they’re more visible. This is what causes the whites of your eyes to appear reddish or pink.1 It can be caused by a virus, bacteria, an irritant (like shampoo, smoke or chlorine) or by allergies. When the inflammation is caused by a virus, bacteria or irritant, it’s non-allergic conjunctivitis. When the inflammation is caused by allergies, it’s called allergic conjunctivitis.

Seasonal Allergies

Common Allergic Conjunctivitis Symptoms:

  • Itchy eyes & eyelids
  • Redness
  • Burning
  • Swollen eyelids
  • Blurred vision
  • Watery eyes
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Non-allergic conjunctivitis can sometimes easily spread from person to person, but allergic conjunctivitis is not contagious.

Difference between allergic and non-allergic Conjunctivitis

Allergic conjunctivitis differs from non-allergic conjunctivitis in a few ways:


Both eyes are usually affected (but may not be as equally affected)

Conjunctivitis watery eyes

Your eyes may water a lot, but they don't become gooey or sticky

Nasal Symptoms

Nasal symptoms, also known as rhinoconjunctivitis, like sneezing and a runny nose often occur along with eye symptoms


What are the causes of Allergic Conjunctivitis?

Allergic conjunctivitis can be caused by both year-round allergies and seasonal allergies. Seasonal allergic conjunctivitis usually happens during pollen season and is connected to allergic rhinitis symptoms. Eye inflammation that occurs year-round can be caused by:

Allergic conjunctivitis can also happen as a reaction to things put in eyes, like contact lens solution or eye drops.    

Am I Allergic?


You may think your itchy eyes are a harmless nuisance, but it’s important to find out what’s causing it – the triggers. Living with conjunctivitis can have a negative impact on productivity and happiness at school and/or work.2 It’s important to determine whether your eye symptoms are caused by a virus or by allergies because they will require different treatments. And learning what may be behind your symptoms now could also help you avoid any potential vision problems in the future.

So, how do you know if your symptoms are caused by an allergy or not? A simple blood test—together with your medical history—can help identify underlying allergen triggers, if you have an allergy. Knowing if you’re allergic and what you’re allergic to can help you, or a loved one, avoid or minimize symptoms. Be sure to consult with your healthcare professional.

Learn more about testing

  1. http://www.mayoclinic.org/diseases-conditions/pink-eye/basics/definition/con-20022732
  2. Epling J. Bacterial conjunctivitis. BMJ Clinical Evidence. 2012;2012:0704.