Allergic conjunctivitis
The conjunctiva is a clear layer of tissue lining the eyelids and covering the white of the eye. Allergic conjunctivitis occurs when the conjunctiva becomes swollen or inflamed due to a reaction to pollen, dust mites, pet dander, mold, or other allergy-causing substances.
Causes
When your eyes are exposed to allergens (which cause allergies), a substance called histamine is released by your body. The blood vessels in the conjunctiva become swollen. The eyes can become red, itchy, and teary very quickly.
Conjunctiva
The conjunctiva is a thin, clear membrane that covers the inner surface of the eyelid and the white part of the eyeball (the sclera). It contains ma...

Itchy
Itching is a tingling or irritation of the skin that makes you want to scratch the area. Itching may occur all over the body or only in one location...

Teary
Watery eyes means you have too many tears in and draining from the eyes. Tears help keep the surface of the eye moist. They wash away particles and...

The pollens that cause symptoms vary from person to person and from area to area. Tiny pollens that may cause allergic symptoms include grasses, ragweed and trees. These same pollens may also cause hay fever.
Your symptoms may be worse when there is more pollen in the air. Higher levels of pollen are more likely on hot, dry, windy days. On cool, damp, rainy days most pollen is washed to the ground.
Mold, animal dander, or dust mites may cause this problem also.
Allergies tend to run in families. It is hard to know exactly how many people have allergies. Many conditions are often lumped under the term "allergy" even when they might not truly be an allergy.
Allergies
An allergy is an immune response or reaction to substances that are usually not harmful.

Symptoms
Symptoms may be seasonal and can include:
- Intense itching or burning eyes
Burning eyes
Eye burning with discharge is burning, itching, or drainage from the eye of any substance other than tears.
ImageRead Article Now Book Mark Article - Puffy eyelids, most often in the morning
-
Red eyes
Red eyes
Eye redness is most often due to swollen or dilated blood vessels. This makes the surface of the eye look red or bloodshot.
ImageRead Article Now Book Mark Article - Stringy eye discharge
- Tearing (watery eyes)
- Widened blood vessels in the clear tissue covering the white of the eye
Exams and Tests
Your health care provider may look for the following:
- Small, raised bumps on the inside of the eyelids (papillary conjunctivitis)
- Positive skin test for suspected allergens on allergy tests
Allergy tests
Allergy skin tests are used to find out which substances cause a person to have an allergic reaction. These substances are called allergens....
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Allergy testing may identify the pollen or other substances that trigger your symptoms.
- Skin testing is the most common method of allergy testing.
- Skin testing is more likely to be done if symptoms do not respond to treatment.
Treatment
The best treatment is to avoid what causes your allergy symptoms as much as possible. Common triggers to avoid include dust, mold and pollen.
Avoid what causes your allergy symptoms
Allergic rhinitis is a group of symptoms that affect your nose. They occur when you breathe in something you are allergic to, such as dust mites, an...

Some things you can do to ease symptoms are:
- Use lubricating eye drops.
- Apply cool compresses to the eyes.
- Do not smoke and avoid secondhand smoke.
- Take over-the-counter oral antihistamines or antihistamine or decongestant eye drops. These medicines can offer more relief, but they can sometimes make your eyes dry. Do not use the eye drops if you have contact lenses in place. Also, do not use the decongestant eye drops for more than 5 days, as rebound congestion can occur.
If home-care does not help, you may need to see a provider for treatments such as eye drops that contain antihistamines or eye drops that reduce swelling.
Video Transcript
How to use eye drops - Animation
I'm Dr. Alan Greene and let's talk about how to put eye drops in. The problem people often have is when you tilt your head back and you see that dropper looming up there and the drops start falling down, it's a natural response to blink. You can send that drop spraying where you don't want it to go. And it can be a little uncomfortable to have that drop come down and strike your eye. If you can keep your eyes open, that's great and it works very well. But if you can't like many people, if not most people, not to worry. There's another way that works very, very well. And what you do is you'll simply tilt your head back hold the dropper right above your eyes with your eyes closed. You don't want the dropper to actually touch the eye because you can contaminate the dropper or your eye, one or the other if there's an infection involved somewhere. Just do like this - couple drops right in the corner and then blink while you're head is still up. And when you do that it will slip right in very comfortably and you'll get the whole dosage in and it works very well.
Mild steroid eye drops can be prescribed for more severe reactions. You may also use eye drops that prevent a type of white blood cell called mast cells from causing swelling. These drops are given along with antihistamines. These medicines work best if you take them before you come in contact with the allergen. Referral to an ophthalmologist before using steroid eye drops should be done since intraocular pressure measurements and a more thorough eye exam (using a slit lamp) is needed.
Outlook (Prognosis)
Symptoms often go away with treatment. However, they can persist if you continue to be exposed to the allergen.
Long-term swelling of the outer lining of the eyes may occur in those with chronic allergies or asthma. It is called vernal conjunctivitis. It is most common in young males, and most often occurs during the spring and summer.
Vernal conjunctivitis
Vernal conjunctivitis is long-term (chronic) swelling (inflammation) of the outer lining of the eyes. It is due to an allergic reaction.

Possible Complications
In severe cases of allergic conjunctivitis, there could be more severe inflammation. This can, rarely, affect your vision.
When to Contact a Medical Professional
Contact your provider if:
- You have symptoms of allergic conjunctivitis that do not respond to self-care steps and over-the-counter treatment.
- Your vision is affected.
- You develop eye pain that is severe or becoming worse.
- Your eyelids or the skin around your eyes becomes swollen or red.
- You have a headache in addition to your other symptoms.
Reviewed By
Deborah Pedersen, MD, MS, Allergy & Asthma Care, PC, Taunton, MA. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
Cioffi GA, Liebmann JM. Diseases of the visual system. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 391.
Rubenstein JB, Patel P. Allergic conjunctivitis. In: Yanoff M, Duker JS, eds. Ophthalmology. 6th ed. Philadelphia, PA: Elsevier; 2023:chap 4.7.
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