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Allergic Conjunctivitis

Written by Ada’s Medical Knowledge Team

Updated on

What is allergic conjunctivitis?

Conjunctivitis is the name for inflammation of the conjunctiva, which is the thin layer of tissue on the inside of the eyelids and which covers the white part of the eye. Also known as pink eye, conjunctivitis is often caused by bacteria (see bacterial conjunctivitis), a virus (see viral conjunctivitis), or allergens, for example seasonal pollen, dust or animal dander. When pink eye is caused by allergies, it is called allergic conjunctivitis. Like all types of pink eye, allergic conjunctivitis is common but not usually serious. 1 2 3

Allergic conjunctivitis usually affects both eyes. The main symptoms include: 1 2 3

  • Pinkness or redness of the eyes
  • Burning, intense itching or a sensation of grittiness in the eyes
  • Watering of the eyes
  • Swollen and/or reddened eyelids
  • Other symptoms of allergy, e.g. itchy nose, sneezing and scratchy throat

Many cases of mild allergic conjunctivitis clear up on their own, without specific treatment, when contact with the causal allergen is minimized or avoided. Applying cool compresses to the eyes and using lubricating eye drops, also known as artificial tears, which are available over the counter, may help to relieve symptoms. However, allergy medications, such as antihistamine tablets and prescription eye drops, may be recommended, particularly for more severe cases of allergic conjunctivitis. 1 2 3

Generally, people make a complete recovery and the condition does not cause any complications. However, in rare cases, allergic conjunctivitis can be very serious and may cause damage to a person’s vision if left untreated. 3 4

Anyone experiencing severe symptoms should see a doctor immediately. These include: 5 6 4

  • Intense pain in the eye
  • Extreme redness in the eye
  • Inability to open the eye
  • Severe sensitivity to light
  • Difficulty seeing
  • Spots or blisters developing near the eye, on the eyelid or nose

Furthermore, if symptoms are mild but do not go away, medical advice should also be sought.

Allergic conjunctivitis can affect people of any age, though it is particularly common in young adults and people with a history of allergic conditions, such as eczema, hay fever, allergic rhinitis and asthma. 7 8 Symptoms may be present for short periods of time, e.g. seasonally, when the allergen is a type of seasonal pollen, or throughout the year, e.g. when the allergen is dust or dander. 9 Allergic conjunctivitis is not contagious, which means that it cannot be passed from one person to another. 2

Feeling unwell? Get a symptom assessment with the free Ada app. Or find out more about how our symptom checker works before you try it for yourself.

Symptoms of allergic conjunctivitis

Generally, allergic conjunctivitis is bilateral, meaning that it affects both eyes. Symptoms tend to develop quickly, and one eye may be more severely affected than the other. Rubbing the eyes may make symptoms worse.

Symptoms include: 1 2 3 4 9

  • Pinkness or redness of the eyes
  • Burning, intense itching or a sensation of grittiness in the eyes
  • Watering of the eyes; the discharge is clear
  • Swollen eyelids, which are red on the inside
  • Slight sensitivity to bright light
  • Other symptoms of allergy, e.g. itchy nose, sneezing and scratchy throat

Depending on the cause and type of allergic conjunctivitis, there may be other symptoms and signs. If you think that you may have allergic conjunctivitis, try using the Ada app to find out more about your symptoms.

Pain is not typically a symptom of allergic conjunctivitis. If it does occur, it tends to be mild. Furthermore, a person’s vision is not usually affected. Severe eye pain may indicate another, more serious condition such as glaucoma, and, if present, medical attention should be sought promptly.

If any symptoms affecting the eyes are severe or vision is impaired, it is important to contact a doctor without delay.

Causes of allergic conjunctivitis

A person’s immune system may be sensitive and react to certain substances such as pollen or molds. These are called allergens and, if they enter the eye, allergic conjunctivitis can result. 4 9

The most common causes of allergic conjunctivitis are the following types of allergens: 1 4 9

  • Pollens, including grass, tree and other plant pollens
  • Molds
  • Dust mites
  • Animal dander, e.g. pet fur

Less common causes of allergic reactions include contact lenses, makeup, eye drops and other substances used in or near the eyes.

Types of allergic conjunctivitis

Depending on the timing, frequency and cause of the allergic conjunctivitis, it may be classified as one of the following: 3 4 9 8 10

Seasonal allergic conjunctivitis

Seasonal allergic conjunctivitis tends to cause mild symptoms for a few weeks, or sometimes a few months, around the same time every year. This is generally caused by pollen and often coincides with hay fever seasons.

Perennial (year-round) allergic conjunctivitis

Perennial allergic conjunctivitis tends to cause mild symptoms throughout the year; this is caused by allergens that are always present in a particular environment, most often the person’s home, such as dust mites, molds or animal dander. Symptoms are typically worse upon waking in the morning.

Acute allergic conjunctivitis

Acute allergic conjunctivitis tends to develop suddenly upon exposure to an allergen, such as animal fur; this can cause fairly severe symptoms, but usually resolves quickly after preventing further exposure to the allergen.

Contact conjunctivitis

Contact conjunctivitis is an allergic reaction caused by a sensitivity to makeup, eye drops, creams or lotions, or other substances used in or near the eyes. It can also affect the outside of the eyelids and is called contact dermatoconjunctivitis in these cases.

Giant papillary conjunctivitis

Giant papillary conjunctivitis is an inflammation caused by a reaction to an object in the eye, most often a contact lens. It sometimes also occurs after eye surgery.

Vernal keratoconjunctivitis

Vernal keratoconjunctivitis is an uncommon inflammatory condition that mostly affects young people, particularly boys, in warm weather conditions. It may be seasonal or perennial (year-round), with symptoms tending to be worse during spring. Vernal keratoconjunctivitis can cause:

  • Severe itching
  • Severe sensitivity to light
  • Cobblestone-like bumps on the conjunctiva
  • Thick, ropy mucus discharge

If left untreated, vernal keratoconjunctivitis may lead to scarring of the eyes and long-term vision problems.

Atopic keratoconjunctivitis

Atopic keratoconjunctivitis is a rare inflammatory condition that mostly affects young adults who have atopic dermatitis (eczema).

It can last for a number of years, potentially causing serious damage to a person’s vision if left untreated. Symptoms include:

  • Itching
  • Redness
  • Sensitivity to light
  • Blurry vision
  • Eyelids may be thick, red and scaly

Conjunctivitis caused by irritants

Conjunctivitis can also be caused by irritation from a variety of substances as opposed to an allergic reaction. These include: 1 2 4 11 12

  • Foreign objects in the eyes
  • Cosmetics and soaps
  • Chemicals, e.g. household cleaning products, chlorine in swimming pools
  • Smoke and fumes
  • Dust and dirt

Mild cases of irritant-related conjunctivitis can generally be treated by removing or avoiding the substance, flushing the eyes with water and applying cold compresses and lubricating eye drops to the eyes. However, more serious cases may require specialist medical treatment.

If symptoms are severe or the irritant is a toxic substance, e.g. a household cleaning product, medical attention should be sought urgently.

Diagnosis of allergic conjunctivitis

When symptoms are mild, a diagnosis of allergic conjunctivitis can often be made without seeing a doctor, and the condition can be treated at home. However, if there is any uncertainty or concern over the eye condition or the symptoms are severe, seeing a doctor is very important.

A doctor will take the person’s medical history and ask whether they have any allergies. They will examine the eyes and assess the signs and symptoms present, taking care to rule out acute viral conjunctivitis, bacterial conjunctivitis, dry eye syndrome and other more serious eye conditions, such as uveitis and keratitis. 2 13

In most cases, it will not be necessary to perform any special tests. However, in some cases a doctor will order allergy tests, e.g. skin patch tests, to identify allergens and confirm the diagnosis. 3

Allergic conjunctivitis treatment

Mild cases of allergic conjunctivitis often clear up when exposure to the allergen is reduced, without special medical treatment. In more serious or long-lasting cases, medication may be necessary to treat the condition.

Home remedies for allergic conjunctivitis

The following home remedies and over-the-counter treatments may help to relieve the discomfort caused by conjunctivitis: 1 3

  • Taking steps to minimize contact with the allergen
  • Applying lubricating eye drops, called artificial tears to the eye; these are available without a prescription
  • Applying a cold compress to the eye, i.e. a clean cloth that has been soaked in water
  • Avoiding rubbing the eyes
  • Avoiding the use of contact lenses until the conjunctivitis has cleared
  • Avoiding the use of eye makeup until the conjunctivitis has cleared

A person with perennial allergic conjunctivitis may wish to consult an allergy specialist to identify the cause of their allergic condition and devise an approach to minimize exposure. 9

Allergic conjunctivitis medication

When allergic conjunctivitis is more serious or does not clear up, medication may be recommended to calm the allergic reaction, provide relief from symptoms and prevent eye complications. Medication may include: 4 9

Eye drops for allergic conjunctivitis

Eye drops for allergic conjunctivitis are generally available over the counter for short-term daily use of two weeks or less, or with a prescription for longer-term use. The types of eye drops recommended for allergic conjunctivitis typically contain antihistamines or mast cell stabilizers. Both histamines and mast cells are involved in an allergic reaction; antihistamines and mast cell stabilizers function to reduce their effects and thereby the severity of the reaction.

Oral medication

Antihistamine tablets are sometimes recommended for allergic conjunctivitis. They can also help to alleviate other symptoms of an allergic reaction, such as a runny nose caused by hay fever. Antihistamines can cause drowsiness, so they may not be suitable for everyone.

Steroid medication

In very severe cases, corticosteroids may be prescribed. This may take the form of:

  • Steroid eye drops
  • Steroid tablets
  • Steroid injections

While they are very effective, corticosteroids can cause serious side-effects and complications, so they are rarely used to treat allergic conjunctivitis.

If symptoms of allergic conjunctivitis are severe or do not improve with treatment, it is important to seek medical advice.

Good to know: If a person has vernal keratoconjunctivitis or atopic conjunctivitis, they will be referred to an ophthalmologist, a specialist eye doctor, for specialized treatment.

Complications of allergic conjunctivitis

While they may cause discomfort in daily life, most cases of seasonal and perennial (year-round) allergic conjunctivitis clear up completely, and complications are rare.

However, in severe cases of contact conjunctivitis and giant papillary conjunctivitis, a person may develop inflammation, ulcers and scarring on the cornea, the front of their eye. This is called keratitis and requires urgent medical treatment to prevent long-term damage to vision. 3 4 14

Severe cases of vernal keratoconjunctivitis and atopic keratoconjunctivitis can also cause long-term damage to the eyes if left untreated.

Allergic conjunctivitis in babies and children

The symptoms of allergic conjunctivitis listed above, as well as the treatment methods, are largely the same in children, toddlers and infants. It is advisable to see a doctor to confirm a diagnosis of allergic conjunctivitis and determine the best treatment approach for a child.

If a newborn baby shows signs of conjunctivitis, it is important to consult a doctor without delay to identify the cause and receive appropriate treatment. Babies sometimes develop strains of viral conjunctivitis or bacterial conjunctivitis that can be very serious if left untreated.

Prevention of allergic conjunctivitis

While it may not be possible to prevent an episode of allergic pink eye, taking steps to limit exposure to known allergens, such as pollen, dust, mold or certain soaps, can help to minimize the likelihood and severity of its occurrence. For example, this may include: 4 15

  • Keeping windows closed and wearing wraparound sunglasses when outside during hay fever season
  • Keeping the house as free of dust and mold as possible and using an air purifier
  • Using hypoallergenic soaps and cosmetics

Other names associated with allergic conjunctivitis

  • Pink eye, or pinkeye
  • Eye inflammation caused by allergies
  • Conjunctivitis allergica

Allergic conjunctivitis FAQs

Q: Allergic conjunctivitis vs. pink eye – what is the difference?
A: Pink eye is the common term for all types of conjunctivitis. Allergic conjunctivitis is one type of pink eye and refers to pink eye that is caused by allergens. Other types of pink eye include viral conjunctivitis and bacterial conjunctivitis.

Q: Bacterial conjunctivitis vs. allergic conjunctivitis – what is the difference?
A: Bacterial conjunctivitis is pink eye that is caused by an infection of the eye(s) with bacteria. Allergic conjunctivitis is pink eye that is caused by allergens which lead to reactions in the eye(s). Some of the symptoms and treatments are different; antibiotic medications may be prescribed to treat bacterial conjunctivitis in severe cases of infection.

Read more about Bacterial Conjunctivitis »

Q: Is allergic conjunctivitis contagious?
A: No, allergic conjunctivitis is not contagious. 2 Unlike viral conjunctivitis, which is caused by a virus, and bacterial conjunctivitis, which is caused by bacteria, allergic conjunctivitis cannot be spread to other people. It is the result of a specific person’s reaction to allergens which they are sensitive to, such as dust or seasonal pollen.

Q: Can you have allergic conjunctivitis in one eye?
A: Usually, allergic conjunctivitis is bilateral, meaning that it affects both eyes. It is possible that in a small number of cases, it may be unilateral, affecting only one eye. An example might be where an allergen comes into contact with just one of the eyes. However, most cases of unilateral conjunctivitis are caused by viruses or bacteria, or exposure to an irritant like a chemical substance, e.g. in a household cleaner spill that may affect the eye, and are therefore not allergic in nature. 16 17

Q: Can allergic conjunctivitis cause blurred vision?
A: Blurry vision can be a symptom of allergic conjunctivitis, as well as other types of conjunctivitis. However, any blurred vision associated with mild cases of conjunctivitis should clear when the person blinks or when discharge is wiped away from the eyes. If the blurriness is severe or persistent, it is important to see a doctor without delay, as a serious eye condition may be present. 4 18 19 20

Q: Can allergic conjunctivitis cause discharge?
A: Yes. A clear, watery discharge is a common symptom of allergic conjunctivitis.

Q: What does allergic conjunctivitis look like?
A: Signs of allergic conjunctivitis include:

  • Pinkness or redness of the eyes and the inside of the eyelids
  • Swelling of the eyelids
  • Watery discharge from the eyes
  • Other typical signs of allergy, such as sneezing and itchiness

Q: Do I have allergic conjunctivitis?
A: If you think that you may have allergic conjunctivitis, you can use the Ada app to find out more about your symptoms.

Q: How long does allergic pink eye take to go away?
A: This depends on the type and cause of the allergic conjunctivitis. Generally, symptoms will begin to improve once exposure to the allergen has been reduced and/or, where necessary, a course of medication has been started.