Allergic Conjunctivitis: Everything You Need to Know
Types, Causes, Treatment, and More
Medically reviewed by Daniel More, MD
Allergic conjunctivitis (AC) is eye inflammation caused by a reaction to an allergen, such as pollen or mold spores. Exposure to allergens can cause the eyes to become red, watery, and itchy. It is a common condition in which the body overreacts to substances that are not usually harmful.
AC is different from other types of conjunctivitis based on what causes it. Two other types, bacterial conjunctivitis and viral conjunctivitis, are highly contagious, meaning they are easily spread from person to person. Conjunctivitis is also called pink eye.
Conjunctivitis affects the inside of the eyelids and the conjunctiva—the membrane that covers the eyeball. The conjunctiva is vulnerable to allergens, especially when pollen levels are high during spring and early fall.
This article will cover types of allergic conjunctivitis, causes, symptoms, treatment, and more.
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Types of Allergic Conjunctivitis
Some types of allergic conjunctivitis are more common than others. Types include:
Seasonal
Perennial
Contact
Giant papillary
Atopic keratoconjunctivitis
Vernal keratoconjunctivitis
Seasonal Allergic Conjunctivitis
Seasonal allergic conjunctivitis, also called allergic rhinoconjunctivitis, is the most common type of AC. It is caused by a reaction to pollens and spores during certain spring and summer months, mainly grass pollen in May and June and ragweed pollen in August and September.
Itching, watery mucus discharge, burning, and redness are common eye symptoms with seasonal AC. In people with hay fever, additional symptoms may affect the nose and throat.
Hay fever, also called allergic rhinitis, causes cold-like symptoms. An allergic response to outdoor and indoor allergens causes it.
Symptoms of hay fever include:
Sneezing with a runny nose or a stuffy nose
Postnasal drip and coughing
Itchy eyes, nose, and throat
Red, watery eyes
Perennial Conjunctivitis
Perennial allergic conjunctivitis is a year-round condition that is caused by an allergic response to animal dander, dust, and other year-round allergens. Symptoms can be similar to those of seasonal allergic conjunctivitis but milder.
Contact Conjunctivitis
A delayed hypersensitivity reaction can be seen with certain substances when they come in contact with the eye. These include:
Latex
Neomycin (an antibiotic)
Nickel
Poison ivy, poison oak, and poison sumac
The reaction can affect the eyelids, conjunctiva, and cornea.
Giant Papillary Conjunctivitis
Giant papillary conjunctivitis (GPC) is a chronic inflammatory condition of the eye due to the eye's reaction to a foreign body. It is controversial as to whether it should be classified as an allergic reaction rather than a foreign-body hypersensitivity reaction.
It results in papillae (small, round bumps) that develop on the upper tarsal conjunctiva (the underside of the eyelid). The bumps develop when the upper tarsus rubs over a foreign object in the eye. Long-term use of soft contact lenses, having an artificial eye, or surgical stitches can cause GPC papillae.
GPC causes the affected eyelid to feel rough, red, or swollen. The papillae will then form and can grow to about the size of a pimple.
Additional symptoms include:
A feeling like something is stuck in the eye
Red, pain, itchy eyes
Blurry vision because of excess eye mucus
Feeling like your contact lens is moving when you blink
Atopic Keratoconjunctivitis
Atopic keratoconjunctivitis (AKC) results from atopy—the genetic tendency to develop allergic conditions. For people with AKC, an abnormal hypersensitivity response leads to inflammation of the eyelid linings and the surface of the eyes.
The onset of symptoms will occur years after the atopy has developed. Symptoms may occur at any time of the year but tend to be worse in the winter months.
Symptoms of AKC include:
Eyelids that are thickened, crusted, and fissured
Sensitivity to light
Itchy eyes
Burning pain in the eyes
Increased tearing
Blurred vision
White discharge from the eyes
Vernal Keratoconjunctivitis
Vernal keratoconjunctivitis (VKC) is a recurrent inflammatory eye disease that occurs seasonally. It tends to present in children and young adults (ages 1 to 22) during the late spring to late summer months.
Eye symptoms of VKC will present in early to mid-childhood. The condition is characterized by cobblestone-like bumps on the upper eyelid and swelling and thickening of the conjunctiva.
Additional eye symptoms may include:
Itchy eyes
Tearing
Discharge
Irritation
Redness
Severe light sensitivity
Blepharospasms (abnormal contractions of the eyelid muscles)
VKC tends to run in families. Risk factors include:
A family history of allergies
Being assigned male at birth
Having an allergic condition like asthma, eczema, and allergic rhinitis
Related: Is It Pink Eye or Allergies?
What Causes Allergic Conjunctivitis?
Environmental allergens cause AC. It is common, affecting about 10% to 20% of the population. Between 40% and 60% of people with allergies have eye symptoms.
AC occurs when the immune system overreacts. This reaction triggers the body to produce histamine (a chemical reaction) to fight off foreign invaders.
Allergens that cause this type of response include:
Chemical scents from household cleaning products or perfumes
Contact lens or contact lens solution
Grass and tree pollen
Household dust
Medicated eye drops
Mold spores
Pet dander
Some people are at a higher risk for AC. This includes people who have allergies.
According to the Asthma and Allergy Foundation of America, more than 100 million people in the United States experience various types of allergies.
In 2021, 81 million Americans were diagnosed with hay fever, which equals around 26% of adults and 19% of children. If you live in an area where pollen counts are high, you likely will be more susceptible to AC than people in other regions.
Allergies tend to run in families. Research has long identified a genetic component for allergies, and there are distinct susceptibility genes for hay fever and allergic asthma.
What Are the Symptoms of Allergic Conjunctivitis?
AC typically presents in both eyes, but not always equally. The most common eye symptoms of AC are:
Intense itching
Redness
Watery or white, stringy mucus discharge
Swollen eyelids
Nasal symptoms, including congestion, runny nose, sneezing, and post-natal drip, may also accompany eye symptoms.
Symptoms of AC may appear quickly once the eyes come in contact with an allergen. However, if eye drops or contact lenses cause AC, symptoms may appear after a few days.
People with seasonal allergic conjunctivitis will have symptoms during the early spring into the summer and sometimes in late summer and early fall. Perennial allergic conjunctivitis can cause symptoms at any time during the year, but symptoms can be worse during certain times of the year (i.e., when pollen levels are high).
Contact conjunctivitis and giant papillary conjunctivitis are not seasonal, so they can occur at any time of the year.
How Is Allergic Conjunctivitis Diagnosed?
Your healthcare provider can diagnose AC by examining your eyes and asking you about signs and symptoms, including nasal symptoms. They will also check to see if an object or other substance (such as an eyelash) might be causing symptoms.
Additional tests may be requested, including:
Allergy skin testing: Allergy skin tests expose the skin to specific allergens and allow your healthcare provider to examine how your body reacts. If you are allergic, the skin where the allergen was placed will become swollen and red.
Blood test: Your healthcare provider may request blood work to check for antibodies against specific allergens, including pollen and mold.
Conjunctival scraping: This test involves scraping conjunctival tissue to examine it for white blood cells called eosinophils. These cells become activated in response to an allergic response.
How Is Allergic Conjunctivitis Treated?
Depending on the severity, AC can be treated with at-home remedies, over-the-counter (OTC) treatments, and prescription medications.
How to Find Relief at Home
Some home remedies might offer relief for AC. This includes:
Avoid allergens: Stay indoors when pollen levels are high. Wash your clothes frequently. Bathe or shower before bedtime.
Use cold compresses: Cold compresses on the eyelids can soothe swollen, irritated eyes.
Avoid contact lenses: Contact lenses should not be used until eye symptoms have resolved.
Do not rub your eyes: Rubbing the eyes can make eye inflammation and irritation worse.
Related: Relief for Eye Allergy Symptoms
OTC Medications
OTC medications can offer symptom relief. Options include:
Artificial tears: Artificial tears can mimic natural tears to dilute the allergen and return eye moisture. They contain eye lubricants such as carboxymethylcellulose sodium. They are available as eye drops, gels, and ointments. Brand names for artificial tears include:
Refresh
Systane
TheraTears
While artificial tears tend to be safe, it is still a good idea to check with your healthcare provider about using these medications long term. Long-term use may lead to chronic dry eye.
Decongestant eye drops: These drops quickly reduce redness by narrowing blood vessels in and around the eyes. Decongestant ingredients include phenylephrine.
These drops work well but are not recommended for long-term use because using these products for long periods can lead to "rebound redness." This means that the eyes become dependent on the drops and will experience redness when you stop using them.
Dual-acting antihistamine-mast cell stabilizing agents: Antihistamine-mast cell stabilizer eye drops are effective treatments for allergic conjunctivitis. They combine antihistamine and mast-cell-stabilizing activity and are considered first-line therapies for providing symptom relief and blocking inflammation related to AC.
OTC brand name antihistamine-mast cell stabilizer eye drops include:
Alaway (ketotifen)
Clear Eyes (olopatadine)
Pataday (olopatadine)
Zaditor (ketotifen)
Oral antihistamines: These drugs can improve AC symptoms, including itching, tearing, and redness. They include:
Allegra (fexofenadine)
Claritin (loratadine)
Clarinex (desloratadine)
Xyzal (levocetirizine)
Zyrtec (cetirizine)
Flonase Sensimist Nasal Spray and Flonase Allergy Relief Nasal Spray (fluticasone): Fluticasone is used to treat seasonal and year-round allergies. It can also help relieve allergy eye symptoms, including itchy, watchy eyes. It is considered a corticosteroid and works in the nose to block the effects of allergens.
Prescription Medications
If at-home remedies and OTC treatments do not help relieve AC, your healthcare provider can prescribe stronger medications to manage symptoms.
Prescription treatments for treating AC might include:
Prescription dual-acting antihistamine and mast-cell-stabilizing agents: In addition to OTC options in this drug class, your doctor can prescribe more potent versions. Examples include Alamast (pemirolast eye drops), Alocril (nedocromil eye drops), Alomide (lodoxamide eye drops), and Opticrom, Crolom, and Gasrocrom (cromolyn eye drops and oral solution).
Allergy shots: If you have allergies that lead to AC, your healthcare provider might recommend allergy shots—a form of treatment called immunotherapy. Each shot contains small amounts of substances that trigger allergic reactions. Over time, the immune system gets used to the allergens and learns to not react to them.
Ocular steroid eye drops: Steroid eye drops can help relieve symptoms of AC. These drops can increase the risk of cataracts (clouding of the lens of the eye), so they should be given only for short periods.
Systemic oral decongestants, antihistamines, steroids, and immunotherapy drugs: These medications can be prescribed for severe AC cases.
Related: How to Treat and Prevent Your Eye Allergies
How Can I Prevent Allergic Conjunctivitis?
The best way to prevent AC is to avoid exposure to environmental allergens. Unfortunately, common allergens, such as pollen, dust mites, and animal dander, can be difficult to avoid.
Some ways to reduce the effects of allergens are:
Stay indoors as much as possible: Staying indoors can help to reduce your exposure to pollen and airborne allergens.
Use an air purifier: Using a good quality air purifier in your home can help keep indoor air clean.
Bathe or shower before bedtime: This will remove potential allergens from the body; washing your clothes and linens frequently can also rid allergens from your environment.
Wash and brush pets regularly: This can help to reduce dander production.
Keep eyes lubricated: Using lubricating eye drops can reduce eye dryness and wash out allergens from the eyes to reduce your risk for AC.
Keep contacts clean: Contacts may trap debris, including allergens, which can irritate the eyes and/or interfere with the fit of the lenses.
Avoid touching your face and eyes: Touching the face and the eyes can lead to the transfer of allergens from the hands and fingers to trigger an allergic reaction. Try to reduce your hand-to-face contact as much as you can. In addition, wash your eyes and face regularly to avoid transferring allergens to the eyes and get rid of allergens.
How Long Does Allergic Conjunctivitis Last?
According to the Centers for Disease Control and Prevention (CDC), allergy symptoms typically improve after the exposure to the allergen stops. Allergy medications and eye drops may also help relieve symptoms and reduce recovery time.
Complications are rare with AC. However, in the long term, allergic conjunctivitis could cause damage to the cornea (the clear dome of tissue at the front of the eye) and affect vision. Medications used to treat the condition may also increase the risk of cataracts.
When to Contact a Healthcare Provider
You should see a healthcare provider if signs of AC do not improve in a few days or if at-home treatments are not helping. You should also reach out to your healthcare provider if you think your eye is infected and if you have pain with blinking.
Additional symptoms that warrant a healthcare provider visit include:
Pain with eye movement
Inflammation of the eyelid or eyelash follicles
Light sensitivity
Signs that eye symptoms indicate a more serious problem and require immediate medical attention include:
Severe eye pain
Impaired vision
Appearance of halos around lights
Difficulty closing the eyelids because of swelling
Dark spots in the center of your field of vision
Difficulty focusing on nearby distant objects
If you are experiencing any of these symptoms, you should call 911 or visit a local emergency room.
Summary
Allergic conjunctivitis, a type of pink eye, results from exposure to allergens, including grass and plant pollen, mold spores, and household dust.
Symptoms include red, itchy, watery eyes. People with allergies are at an increased risk for AC. Allergies tend to run in families.
AC can make you miserable, but fortunately, there are various treatment options. These include avoiding triggers, taking OTC medications, including eye drops and antihistamines, and taking ocular and oral prescription medicines. AC can also be prevented by avoiding allergens, using air filters, and keeping your home clean and dust-free.
Read the original article on Verywell Health.
