The Difference Between Allergies and Pink Eye

Even though they have different causes, pink eye and allergies exhibit some of the same symptoms. It's easy to confuse them.

"Symptoms can really look the same," said Sunil K. Saini, MD, a member of the American Academy of Allergy, Asthma, and Immunology and an allergist in Upland, California. "In both conditions, you typically are going to have redness in your eye and tearing."

Pink eye and allergies are both types of conjunctivitis, a term that means inflammation of the conjunctiva, according to an article from the September 2015 issue of Primary Care: Clinics in Office Practice. The conjunctiva is the outer membrane layer that covers your eyeball and the inside of your eyelids.

So what's the difference between pink eye and allergies? It comes down to the cause of that inflammation. The condition known commonly as "pink eye" is an infection caused by bacteria or a virus. Allergies are triggered by various irritants, like pollen or pets.

Pink eye (bacterial or viral) and allergies, especially seasonal allergies, aren't the only causes of eyes that look pink or red, but they're among the most common.

Types of Conjunctivitis

To understand the difference between pink eye and allergy symptoms–and get the proper treatment–it helps to know the different types of conjunctivitis.

Allergic conjunctivitis

On top of red eyes and tearing, allergies can cause your eyes to itch and feel sore or burning. Allergic conjunctivitis symptoms also include:

• A gritty feeling in your eye
• Eye swelling
• Sneezing
• Runny nose

Healthcare providers may notice other clues. "If we look under the eyelid, we may find bumps indicative of allergies called papillae," explained Jules Winokur, MD, an ophthalmologist with Lenox Hill Hospital in New York City. Put all these symptoms together, and there's a good chance you're feeling the effects of your allergies.

Allergic conjunctivitis isn't contagious, and the symptoms can be treated relatively easily. Although traditional over-the-counter allergy remedies may help, allergists recommend "focused treatment," Dr. Winokur said, aka eye drops. If you can, try to stay away from whatever allergens are bothering you too.

Healthcare providers may prescribe prescription medications, allergy shots, or steroids for more severe allergies.

If you wear contact lenses, take them out at the first sign of redness and irritation. You should do this whenever your eyes are irritated. "Wearing contact lenses puts you at a higher risk of infections," said Dr. Winokur.

Bacterial conjunctivitis

The common name for both bacterial and viral conjunctivitis is pink eye. The 2015 Primary Care: Clinics in Office Practice article notes that bacterial pink eye is less common than viral pink eye and has symptoms that differ from viral pink eye and allergies.

According to a 2020 review published in The Journal of Ophthalmic and Vision Research, bacterial conjunctivitis symptoms:

• Crusty yellow or green discharge from your eyes
• Eyelids that are stuck together
• Redness often in just one eye (though it can appear in both)

Itchy eyes aren't usually part of the equation.

For bacterial infections, healthcare providers turn to antibiotic ointments or eye drops. "We can use a much higher concentration than you could get [from an oral antibiotic]," explained Dr. Winokur.

This type of pink eye is contagious, so be diligent about washing your hands if you have it or are around someone who does.

Viral conjunctivitis

The review from The Journal of Ophthalmic and Vision Research states that this is the most common form of pink eye, and it can be hard to stop it from spreading.

"It's highly contagious. You can get it just the same way you get a cold," said Dr. Saini. That means not just from other people but also by touching surfaces infected people may have touched and then touching your eyes.

Viral conjunctivitis also often goes along with a cold. "It's usually related to a history of being sick or being with someone who is sick," said Dr. Winokur.

In addition to red eyes, you may have a discharge that is more watery than crusty.

Viral pink eye usually goes away on its own after a week or two, but it can sometimes turn into bacterial pink eye. "When a person has viral pink eye [and] they keep rubbing their eyes, they could introduce bacteria," said Dr. Saini.

There's no cure for viral pink eye, but there are ways to ease the discomfort. "It's mostly supportive care like cool compresses and artificial tears," said Dr. Winokur.

Remember: You're going to be contagious for as long as you have symptoms, Dr. Saini cautioned. Make sure you wash your hands if you have pink eye or have been near people who have it.

Mechanical irritation conjunctivitis

When you get something in your eye, it's considered mechanical irritation conjunctivitis. Irritants can include food, makeup, or chemicals.

"The symptoms are the same or similar to allergies: redness and teariness," Dr. Saini said.

The remedy for this type of conjunctivitis is very straightforward: Get the irritant out as quickly and safely as possible. Since chemicals can damage the eye, it's a good idea to call your healthcare provider or get medical attention.