Allergic conjunctivitis types, causes and symptoms

What is allergic conjunctivitis? 

Allergic conjunctivitis occurs when the conjunctiva (the thin layer of tissue that covers the eye and lines the inside of the eyelids) becomes inflamed due to allergy-triggering factors such as dust, pet dander, pollen, mold and more.

The condition is common and affects over 20 percent of the population. Because it is so common, there are several remedies available, and it is typically easy to treat. Allergic conjunctivitis is also not contagious or infectious, unlike other types of conjunctivitis. 

In order to treat allergic conjunctivitis, it’s important to eliminate the allergen that may be affecting your eyes, as the condition usually lasts as long as the specific irritant is present.

SEE RELATED: Conjunctivitis symptoms, causes and treatments

Types

Allergic conjunctivitis can be acute (occurring due to sudden exposure to an irritant) or chronic (occurring on a long-term basis).

Acute allergic conjunctivitis

Acute allergic conjunctivitis occurs when the eyes are suddenly exposed to an allergen or irritant. It can occur with seasonal allergies or when the eyes are exposed to an irritant such as soap, cosmetics or environmental pollutants.

Many times, acute allergic conjunctivitis is mild and can be easily treated with over-the-counter remedies. However, it can be severe in some cases. Other symptoms such as nasal congestion can also occur during a seasonal allergy flare-up.

Chronic allergic conjunctivitis

Chronic allergic conjunctivitis occurs continuously, or nearly continuously, due to ongoing exposure to allergens such as dust and pet dander. It can be more severe than acute allergic conjunctivitis. 

There may be less visible inflammation with this type of allergic conjunctivitis, though burning and itching still take place. Some may also experience light sensitivity with chronic allergic conjunctivitis.

Chronic allergic conjunctivitis can sometimes be confused with dry eye syndrome and other conditions, so it is important to tell your eye doctor about any allergies you have that may affect your eyes for proper diagnosis and treatment.

Causes

Various indoor and outdoor allergies can cause irritation in the eyes. When this happens, the body’s natural response is to release a substance called histamine, which can cause inflammation. Blood vessels in the conjunctiva then become swollen, and eyes may begin to water. 

Both acute and chronic allergic conjunctivitis may flare up due to allergens such as the following:

• Pollen.

• Dust mites.

• Pet dander.

• Seasonal allergies.

• Mold spores.

• Certain fragrances.

When pollen counts are higher or in situations when you are introduced to an animal whose dander you are sensitive to, the reaction in your eyes may be even worse.

Risk factors

Those who suffer seasonal allergies may be at a higher risk for developing allergic conjunctivitis. Allergies often run in families, so if one of your parents or family members experiences allergic conjunctivitis, your chances may be higher.

If you have sensitive skin or are sensitive to the fragrances of perfumes, soaps or certain cosmetics, you may also experience allergic conjunctivitis. Be sure to pay attention to any products and allergens that cause irritation in your eyes so that you can avoid them in the future.

Symptoms

Common symptoms of allergic conjunctivitis include:

• Red eyes.

• Severe itching in the eyes. 

• Burning of the eyes.

• Tearing and watery discharge.

• Inflamed, puffy eyelids (especially after waking up in the morning).

Diagnosis

Seeing an eye doctor for an eye exam is an important first step in discovering what your condition is and what might have caused it. Since allergic conjunctivitis can present similar symptoms to other eye conditions, it’s important to see an eye doctor to pinpoint the exact problem you are experiencing. 

In addition to an eye exam, your doctor may suggest testing your conjunctival tissue for a type of white blood cells called eosinophils, which are present in tissue that is affected by an allergic reaction. This testing is particularly useful in diagnosing chronic allergic conjunctivitis.

If you are diagnosed with allergic conjunctivitis, your doctor may suggest that you have allergy testing done to understand what is triggering a reaction in your eyes (especially if your condition does not respond to initial treatment). If allergy testing is needed, it will be performed by an allergist through skin and/or blood testing.

Treatment

Allergic conjunctivitis is often treatable at home and with over-the-counter medications. Some of these remedies can include:

• Placing a cool compress over the eyes.

• Using lubricating eye drops (artificial tears).

• Taking over-the-counter antihistamines such as Benadryl, Zyrtec or Claritin.

• Avoiding irritants and allergens whenever possible.

In severe cases, your doctor may prescribe antihistamine or steroid eye drops or other medication to help treat your condition. Note: if you use antihistamine or steroid eye drops, always make sure to remove your contact lenses (if you wear them) before administering the drops.

SEE RELATED: Home remedies for pink eye 

Prevention

If you have known allergies, it’s best to stay away from them to prevent flare-ups of allergic conjunctivitis. This may not be possible in some circumstances, but following these precautions can help prevent negative reactions as well:

• Wash your hands with soap and water often.

• Refrain from touching or rubbing your eyes.

• Reduce indoor allergies by cleaning, vacuuming and changing air filters regularly.

• Wear eye protection outdoors (particularly sunglasses or safety goggles when doing yardwork) to keep pollen and other harmful particles from entering your eyes.

SEE RELATED: 10 pink eye (conjunctivitis) prevention tips 

Allergic conjunctivitis vs. other conjunctivitis

Allergic conjunctivitis is one of the most common types of conjunctivitis, next to the viral and bacterial types. The latter two types of conjunctivitis can cause infection, while allergic conjunctivitis mainly involves irritation and inflammation. 

It is also important to note that allergic conjunctivitis is not contagious, unlike bacterial and viral conjunctivitis.

Conjunctivitis as a whole is often referred to as “pink eye,” though the term technically only applies to viral conjunctivitis. 

It can be difficult to determine what kind of conjunctivitis you are experiencing, as they can all present similar symptoms. That being said, it is important to see an eye doctor as soon as possible to receive a proper diagnosis and treatment plan.

Similar symptoms of allergic, viral and bacterial conjunctivitis include: 

• Feeling of a foreign object in the eye.

• Watery or sticky discharge.

• Eye redness and irritation.

Differences between allergic, viral and bacterial conjunctivitis include:

• Severe itching is associated only with allergic conjunctivitis.

• Viral and bacterial conjunctivitis are highly contagious, unlike allergic conjunctivitis.

• Allergic conjunctivitis affects both eyes at once, while it can begin with one eye in cases of bacterial and viral conjunctivitis.   

• Bacterial conjunctivitis can be sight threatening if not treated.

SEE RELATED: Pink eye (conjunctivitis) causes 

When to see an eye doctor for allergic conjunctivitis

It’s important to see an eye doctor to identify what type of conjunctivitis you are experiencing and to receive proper treatment when you begin to notice symptoms. Contact your eye care professional if the following occur as well:

• Treatment (whether prescribed or over-the-counter) does not help your condition.

• Eye pain develops or worsens.

• Vision becomes affected.

• Additional symptoms such as a headache occur.

• Other parts of the eye, including the eyelids and skin around the eyes, begin to swell or turn red.

You should also let your eye doctor know of any eye allergies you have experienced in the past. This will help them provide the best care possible for your eyes.

READ MORE: Eye allergies vs. pink eye: What’s the difference?

Page published on Wednesday, June 16, 2021