Pink Eye vs. Allergies: How to Tell the Difference - Verywell Health

Pink eye is a term commonly used for conjunctivitis, which is inflammation or infection of the conjunctiva, the transparent membrane that covers the white part of the eyeball and inner eyelid. Similar symptoms of redness, itching, and watering of the eyes can also be seen in allergies (allergic conjunctivitis).

Infectious forms of pink eye may be caused by bacteria or a virus. Allergies are an abnormal immune system reaction triggered by usually harmless substances (allergens) such as pet dander or pollen.

Conjunctivitis accounts for approximately 6 million cases annually in the United States. The most common type of infectious conjunctivitis in the U.S. is viral conjunctivitis. Allergic conjunctivitis is also very common, affecting up to 30% of people at some point in their life.

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Pink Eye vs. Allergies

The term pink eye is most commonly used for the types of conjunctivitis caused by infection rather than when it is caused by non-infectious irritation or inflammation, such as with allergies.

Some forms of conjunctivitis (bacterial, viral) are highly contagious. Others may be triggered by an allergy (such as to dust, pet dander, or pollen) or exposure to harsh chemicals (such as chlorine, fumes, or hydrogen peroxide), which are non-contagious.

Is Pink Eye Contagious?

Pink eye can be contagious depending on the type you have. Infectious conjunctivitis caused by viruses and bacteria can be easily transmitted to others.

It's not contagious if it's caused by allergies, an autoimmune reaction, or a toxic chemical. If you have a sudden onset of pink eye, consult your healthcare provider to determine whether it might be infectious and if you need treatment.

Pink Eye

Common symptoms of pink eye include the following:

• Pink or red color in the white of the eye(s)
• Swelling of the conjunctiva (the thin layer that lines the white part of the eye and the inside of the eyelid) and/or eyelids
• Increased tear production
• Feeling like a foreign body is in the eye(s) or an urge to rub the eye(s)
• Itching, irritation, and/or burning
• Discharge (pus or mucus)
• Crusting of eyelids or lashes, especially in the morning
• Contact lenses that feel uncomfortable and/or do not stay in place on the eye

Allergy Symptoms

If allergies are causing conjunctivitis, you may see other symptoms such as:

• Sneezing
• Itching of the nose or roof of the mouth
• Nasal congestion
• Runny nose
• Throat irritation
• Dark circles under the eyes

Causes

Pink eye is a common condition with many possible causes. They can be classified into several types: viral conjunctivitis, bacterial conjunctivitis, allergic conjunctivitis, chemical conjunctivitis, and autoimmune/inflammatory conjunctivitis. The list below discusses each type of pink eye and how they are caused:

• Viral conjunctivitis: This is the most common cause of pink eye. Viral conjunctivitis can spread through hand-to-eye contact or contaminated objects. It is linked to a number of viruses, including adenoviruses (often responsible for epidemic keratoconjunctivitis), the measles virus, and herpes simplex virus.
• Bacterial conjunctivitis: Bacteria that cause conjunctivitis can be transmitted by touching your eyes with unclean hands or sharing things like eye makeup, eyedrops, contact lens cases, or towels. It can be caused by bacteria including Staphylococcus aureus, Streptococcus pneumoniae, Moraxella catarrhalis, or Haemophilus influenza.
• Allergic conjunctivitis: Any allergy trigger can cause allergic conjunctivitis, including seasonal allergies, food allergies, or contact dermatitis of the eyelids (often caused by rubbing the eyes). One unique type, called giant papillary conjunctivitis (GPC), is triggered by the ongoing presence of a foreign body in the eye, such as contact lenses.
• Chemical conjunctivitis: This is also known as toxic conjunctivitis. Chemical conjunctivitis can be caused by anything in the environment that irritates or injures the eye, such as smoke, fumes, acid exposure, or chlorine from a pool.
• Autoimmune/inflammatory conjunctivitis: This may be caused by conditions such as ocular rosacea, dry eye syndrome, Sjogren's syndrome, and thyroid eye disease.

Treatment

The treatment for pink eye depends on the underlying cause. In some cases, the symptoms may resolve on their own. In other cases, they may require treatment with topical eye drops or oral medications to treat an underlying infection.

To help relieve some of the inflammation and dryness caused by pink eye, you can also use cold compresses and artificial tears, which you can purchase over the counter without a prescription.

You should also stop wearing contact lenses until your ophthalmologist (eye doctor) says it's OK to start wearing them again. If you do not need to see an ophthalmologist, do not wear your contacts until you no longer have symptoms of pink eye.

Common pink eye treatment approaches include:

• Bacterial conjunctivitis: Antibiotic eye drops or topical ointments can be prescribed by your healthcare provider. In some cases, an oral antibiotic may be prescribed. Symptoms tend to resolve within three to four days. Be sure to complete the course of antibiotics or the infection may return.
• Viral conjunctivitis: Comfort measures such as cold compresses and artificial tears are generally recommended and the infection will usually resolve in one to two weeks. If caused by herpes simplex virus or varicella-zoster virus, a healthcare provider may prescribe antiviral drugs.
• Allergic conjunctivitis: Removal of the allergy trigger is the best treatment. Antihistamines and/or topical steroid eye drops may also be prescribed.
• Chemical conjunctivitis: Treatment involves flushing the eyes with water or a saline wash. Serious cases may require topical steroids. Severe chemical injuries, particularly alkali burns, are considered medical emergencies and are treated in the same way as a burn injury.
• Inflammatory/autoimmune: The treatment will depend on the underlying condition. Topical antihistamines, mast cell stabilizers (medications to prevent allergic disorders) and non-steroidal anti-inflammatory agents (NSAIDs) may be used. In severe cases, surgery may be required.

Prevention

To prevent non-infectious and infectious conjunctivitis, consider following these tips:

• Wash hands regularly.
• Keep your hands away from your eyes.
• Avoid sharing personal items, like towels, face cloths, make-up brushes, and anything that comes into contact with the eye or eyelid.
• Wear protective eyewear or use a fume hood when working with chemicals.

The best way to prevent an allergic reaction is to avoid the substance that you're allergic to, although this is not always easy or practical. Consider the following tips to minimize exposure to an allergen:

• For pollen allergies, limit your time outdoors in high pollen times, keep your windows closed, and use central air conditioning with a certified filter attachment.
• Keep your home as dry as possible (low humidity) with a dehumidifier during the summer. High humidity indoors (above 50%) can encourage dust mites and mold growth.
• Keep pets outside as much as possible or limit them to one area of the house (preferably without carpet).
• If you are allergic to certain foods or ingredients, check the label for the list of ingredients to avoid an allergic reaction.
• Cover exposed skin with proper clothing to avoid insect bites.

When to Talk to Your Healthcare Provider

It's not always necessary to see your healthcare provider for conjunctivitis. However, seek medical attention as soon as possible if your symptoms are severe or don't improve within a week. That said, you should see a healthcare provider if you have conjunctivitis along with any of the following:

• Pain in the eye(s)
• Sensitivity to light or blurred vision that does not improve when discharge is wiped from the eye(s)
• Intense redness in the eye(s)
• Symptoms that get worse or don't improve, including pink eye thought to be caused by bacteria which does not improve after 24 hours of antibiotic use
• A weakened immune system, for example from HIV infection, cancer treatment, or other medical conditions or treatments

Summary

Conjunctivitis (inflammation of the white of the eye) is usually called pink eye when due to an infectious cause, but it may also be caused by allergies, chemical exposure, and inflammatory conditions. Symptoms include redness, itching, and watering of the eyes.

Infectious pink eye may be caused by viruses or bacteria. Allergic conjunctivitis may be triggered by allergens such as pollen, pet dander, mold, or dust mites. Allergies may also produce nasal congestion and sneezing.

To prevent pink eye, frequently wash your hands and refrain from sharing personal items. To prevent an allergic reaction, attempt to avoid the substance that you're allergic to. Treatments vary depending on the type of pink eye and allergy you have. If your symptoms do not improve or become worse, see your healthcare provider.

A Word From Verywell

Pink eye is usually a minor eye infection, but it can develop into a more serious condition if left untreated. While many forms of pink eye can be treated by a healthcare professional, severe cases (or those that fail to respond to therapy) should be seen by an ophthalmologist.

Frequently Asked Questions

• Pink eye (known as conjunctivitis) is an inflammation or infection of the conjunctiva, the transparent membrane that covers the white part of the eyeball and inner eyelid. Causes of pink eye include bacteria, viruses, allergens, and more.

  Dry eyes occur when tears evaporate too quickly or if the eyes produce too few tears. Medications or staring at a computer screen too long can cause dry eyes.

• Seasonal allergies, which occur when your immune system overreacts to a harmless substance (an allergen), are commonly misdiagnosed as infectious pink eye.

• Pink eye is characterized by redness and a gritty sensation in your eye, along with itching.

• Pink eye can be spread through direct contact with the eye by hands or objects that are contaminated with the virus or bacteria. It can also spread via respiratory tract droplets.