Pink eye vs. allergies: Compare types of pink eye

Both cause red, watery, and itchy eyes but there are different causes and treatments for pink eye vs. allergies

By Lindsay Modglin | Updated on Mar. 3, 2022 Medically reviewed by Anne Jacobson, MD, MPH

Conjunctivitis, often known as “pink eye,” is a common eye condition. Inflammation of the conjunctiva, the membrane that covers the inside of the eyelid and white part of the eye, causes one or both eyes to appear red or pink. Some types of pink eye are caused by viruses or bacteria and are easily spread to other people, especially among children in daycare centers and schools.

Allergic conjunctivitis (eye allergy) is also very common and produces symptoms similar to infectious pink eye. When the eyes come in contact with an allergen, the immune system produces histamines, which are chemicals that help protect against substances the body perceives to be harmful. Unlike infectious forms of pink eye, allergic conjunctivitis isn’t contagious and is often accompanied by symptoms of hay fever.

So do you have allergies or pink eye? Compare the causes and symptoms of allergic and infectious pink eye to determine the best treatment.

Causes

Infectious pink eye

“Pink eye can be caused by a virus, bacteria, allergies, or inflammation called blepharoconjunctivitis,” explained Yuna Rapoport, MD, an NYC-based board-certified ophthalmologist.

Viral pink eye: caused by viral infections, including viruses that cause the common cold.
Bacterial pink eye: most commonly caused by Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae, or Moraxella catarrhalis. Gonorrhea and chlamydia may cause more serious infections, especially in newborns.

Fungi or parasites can also cause pink eye, but this isn’t as common.

Allergic pink eye

“Usually allergic conjunctivitis is caused by environmental pollen,” Dr. Rapoport says. Seasonal allergies can contribute to the development of eye allergies. Common outdoor allergens include grass and tree pollen. Pet dander, dust mites, and mold are also common causes of allergies. Some people may be triggered by certain perfumes or smoke.

“Oftentimes, bumps called papillae are found on the underside of an eyelid. These can be triggered by chronic contact lens wear, specifically of rigid gas permeable lenses,” continues Dr. Rapoport. This type of allergic reaction is called giant papillary conjunctivitis (GPC).

Infectious vs. allergic pink eye causes
Infectious	Allergic
Viruses Bacteria Fungi Parasites	Environmental pollen from grass, trees, and other plants Indoor allergens from pets, dust, and mold Irritants like smoke and perfume Chronic contact lens wear

Prevalence

Pink eye

Pink eye is very common. In fact, it’s the most common eye condition in children and adults, according to the Centers for Disease Control and Prevention (CDC). An estimated 6 million people contract acute conjunctivitis in the United States every year.

Conjunctivitis accounts for around 1% of primary care office visits in the United States. Viral conjunctivitis is the most common infectious form of pink eye in adults, while bacteria cause 50% to 75% of infectious cases in children. Allergic conjunctivitis is the most common cause of pink eye overall.

Allergies

More than 50 million Americans experience allergies each year, a number that has continued to rise over the last 50 years. Although not all allergic conditions involve the eyes, the American Optometric Association states that seasonal and perennial ocular allergies account for 95% of all allergic conjunctivitis in the U.S.

Symptoms

Infectious pink eye

The most common symptoms of infectious pink eye are irritation and a pink or red color in one or both eyes. A crust-like film over the eyelid or eyelashes may make it hard to open the eyes, especially in the morning. There may be either watery or thick discharge, blurred vision, or the sensation that something is stuck in the eye.

Allergic pink eye

Allergies affecting the eye can cause symptoms that are similar to an infection. The white of the eye may be pink or red. In allergic conjunctivitis, the eyes often feel itchy or irritated with excessive clear drainage, or tearing. A person with allergies may also experience puffy, swollen eyelids and light sensitivity. It’s common for someone with allergic pink eye to also experience general allergy-like symptoms, including sneezing, runny nose, and scratchy throat.

Infectious vs. allergic pink eye symptoms
Infectious	Allergic
Watery eye(s) Itchy eye(s) Pink or red eye(s) Discharge—usually yellow or green Blurred vision Sticky sensation on the eyelid(s) or eyelashes	Watery discharge Itchy eye(s) Pink or red eye(s) Blurred vision Sensitivity to light Swollen, puffy eyelid(s) Sneezing Runny nose Scratchy throat

Diagnosis

A diagnosis of pink eye is often based on patient history, current symptoms, and a thorough examination of the eye. Many people see their primary healthcare provider for diagnosis, but optometrists and ophthalmologists (eye care specialists) can also diagnose pink eye. An instrument that lights up and magnifies the eye may be used to more closely examine blood vessels, swelling, and to look for anything that may be causing irritation beneath the eyelid.

Rarely, a sample of discharge or a few cells from the inside lining of the eye may be needed to diagnose the specific cause of pink eye. The sample may be sent to a laboratory for a culture to find an infectious cause, or examined under a microscope to suggest an allergic cause. This is usually only needed if the case of pink eye is severe or not improving after treatment is complete.

People who have severe eye pain or sensitivity to light, who have constant blurred vision or a loss of vision in one eye, or who have swelling and redness of the face around the eye, need to be evaluated and treated immediately.

Treatments

Pink eye

The treatment for pink eye depends on the cause.

Viral pink eye: This usually clears on its own but should be evaluated again if the symptoms are getting worse or not improving within 10 days. Cool compresses and artificial tears may help with symptom relief. Antibiotic eye drops may be prescribed if the cause is unclear, but antibiotics will not treat a virus. Some specific and serious forms of viral eye infections, such as herpes simplex, may need treatment with antiviral medications.
Bacterial pink eye: A healthcare professional may prescribe an antibiotic drop or ointment to prevent the pink eye from spreading or becoming worse, although mild infections may also clear on their own. Some kinds of bacterial conjunctivitis may be serious, especially in newborn babies, and these should always be evaluated by a healthcare provider.
Allergic pink eye: This can be treated with both over-the-counter and prescription medications. Antihistamines come in both oral forms and eye drops and can be used to help block the effects of histamine in the body. Steroid and immunotherapy treatments may be prescribed in cases of severe or recurrent allergic pink eye.

More on treatment of allergies

Allergy symptoms can be decreased or avoided when the allergy irritant is known. Allergies can be treated with both over-the-counter and prescription medications, including:

Antihistamines, including Benadryl (diphenhydramine), Zyrtec (cetirizine), Allegra (fexofenadine), Claritin (loratadine), Xyzal (levocetirizine), and Clarinex (desloratadine), work to block the body’s release of histamines to prevent an allergic response.
Steroid nasal sprays, including Nasacort Allergy 24hr (triamcinolone), Rhinocort Allergy (budesonide), Flonase Allergy Relief (fluticasone).
Combination drugs combine two or more medications into a single dosage to help manage multiple symptoms. Over-the-counter combination drugs include Allegra-D (fexofenadine and pseudoephedrine), Benadryl Allergy and Sinus (diphenhydramine and pseudoephedrine), Claritin-D (loratadine and pseudoephedrine), and Zyrtec-D (cetirizine and pseudoephedrine).

Artificial tears can also be used to prevent dry eyes and help prevent irritation from allergens.

Treatment of infectious vs. allergic pink eye
Infectious	Allergic
Supportive treatment (viral) Antibiotics (bacterial)	Avoidance of allergens Antihistamines Steroid nasal spray Combination drugs

Risk factors

Pink eye

The most common risk factors for different forms of pink eye include:

Exposure to someone with bacterial or viral pink eye
Exposure to an irritant (allergic conjunctivitis)
Overwearing contacts, especially gas permeable lenses

Allergies

Risk factors for allergies include:

Having a family history of allergies
Having asthma
Being a child

Prevention

Infectious pink eye

“The main way of preventing infectious pink eye is to have good hand hygiene, washing of hands, and avoid rubbing your eyes with dirty hands,” explained Amir Moarefi, MD, an eye physician based in Long Beach, California. “Make sure you use hand sanitizer before touching your face when you have touched any unsanitary surfaces.”

Other tips for preventing infectious pink eye include using fresh washcloths and towels every day and replacing eye makeup products such as eyeliner and mascara frequently. It’s also important to stay on top of your eye health by seeing an eye doctor regularly.

Allergic pink eye

Since pollen is a common cause of eye allergies, it is best to limit exposure as much as possible. Avoid opening the windows in the home and car and limit outside exposure on high pollen days. As with infectious pink eye, hand hygiene is also important. Wash hands frequently, especially after handling animals.

“Certain oral medications and drops can be used to prevent the allergies in the eye,” says Dr. Moarefi. Antihistamines come in both oral form and eye drops, and work to block histamine to prevent allergy symptoms, including irritated and watery eyes.

How to prevent infectious vs. allergic pink eye
Infectious	Allergic
Good hand hygiene Avoiding touching the face	Preventive oral antihistamines Preventive antihistamine eye drops Limit allergen exposure

When to see a healthcare provider for pink eye

If you have symptoms of pink eye, visit a healthcare provider to determine the cause. Infectious and allergic pink eye can both be managed with the proper diagnosis.

Frequently asked questions about pink eye

How do I know if I have an infection or allergies?

Infections and allergies can both cause inflammation to the conjunctiva, so symptoms are often similar. One difference may be the color of eye drainage. Some infections cause a yellow-green discharge, but allergy drainage is usually clear. The best way to determine the cause of eye discomfort is to see a healthcare provider as soon as symptoms appear.

What looks like pink eye but isn’t?

Other conditions may cause a red or pink eye, such as iritis and uveitis (inflammation of other parts of the eye), blepharitis (inflammation of the eyelids), stye (red lump on the eyelid), or chalazion (inflammation of the gland along the eyelid). A foreign body or substance in the eye, or an injury causing damage to the surface of the eye can also cause symptoms. Injuries, exposure to chemicals or other toxic substances, severe pain, or loss of vision should always be evaluated immediately.

What gets rid of pink eye fast?

The fastest way to get rid of pink eye is to see a healthcare professional for proper diagnosis, treatment, and additional medical advice.

Will pink eye go away by itself?

Viral pink eye usually goes away by itself. Home treatments may help ease discomfort. Over-the-counter eye drops and warm or cool compresses to the affected eye(s) can help soothe irritation. More serious cases of pink eye need to be treated with medications prescribed by a healthcare provider.

What happens if pink eye goes untreated?

Viral and allergic pink eye will usually heal on their own within seven to 14 days. Severe bacterial infections can cause permanent damage if left untreated. It’s important to see a healthcare provider for proper treatment. Make sure to finish any antibiotic treatment to prevent pink eye from returning.

What does eye allergy look like?

Eye allergy, or allergic pink eye, causes redness and irritation to the whites of the eye. There is usually excessive watering. Many people also report feeling a “gritty,” burning sensation. The eyelids or skin around the eyes may be swollen or puffy.