Pink eye, or conjunctivitis, is a broad term that most people use to describe an infection or inflammation of the eye, specifically the “conjunctiva” tissue underneath the eyelids. When you have pink eye, one or both eyes may become red, itchy, and watery.

Most people who use the term pink eye are referring to a bacterial or viral infection in the eye, but pink eye can also be caused by allergies. This is called allergic conjunctivitis. Irritants, like smoke, can also cause pink eye.

It can be difficult to tell whether you have the bacterial or viral pink eye or the kind caused by allergies or other irritants. But it’s an important distinction to make because bacterial and viral pink eye is highly contagious, while allergic pink eye is not. Treatment for allergic pink eye is also different than treatment for infectious pink eye.

Figuring out if you have pink eye caused by an infection versus pink eye caused by allergies or other irritants comes down to the specifics of your symptoms and your medical history.

The symptoms of pink eye caused by allergies are similar to pink eye caused by an infection. These symptoms may include:

  • itchy eyes
  • pink or red-toned eyes
  • watery eyes
  • burning eyes
  • thick discharge that builds up at night

However, there are a few key differences in symptoms between viral, bacterial, and allergic pink eye:

SymptomViral Bacterial Allergic
mild itching
pink or red-toned eyes
watery discharge
thick yellow-green discharge that may form a crust
intense itching
burning eyes
tends to occur in both eyes
mild pain
gritty feeling in the eye
usually accompanies a cold or other type of respiratory infection
swelling or tenderness in the area in front of the ears

Allergic conjunctivitis tends to happen seasonally when pollen counts are high, but it can happen at any time of the year depending on your allergies. If you’re allergic to dust or pet dander, for example, you may notice that your symptoms worsen when you dust the house or groom your pet.

Pink eye is a general term for inflammation of the conjunctiva. This is the mucous membrane that conceals the front of the eye and lines the inside of the eyelids. In the medical world, pink eye is referred to as conjunctivitis.

The conjunctiva can become inflamed for many reasons. Most commonly, pink eye is caused by:


Conjunctivitis is often caused by one of the same viruses that cause the common cold or other respiratory infections, such as adenovirus. You might get viral conjunctivitis if you come in contact with someone who is sick with a cold.


Bacterial conjunctivitis is most often caused by the same type of bacteria that cause strep throat and staph infections, such as Streptococcus and Staphylococcus.


Common allergens, like pollen or dust, can cause pink eye in one or both of your eyes. Allergens make your body produce histamines. The histamines cause inflammation. In turn, this results in the symptoms of allergic conjunctivitis. Allergic pink eye is usually very itchy. People with seasonal allergies (hay fever) are more likely to get allergic conjunctivitis.


If a chemical or foreign substance accidentally gets into your eyes, they may become irritated or inflamed. Examples of irritants include chlorine, a chemical commonly found in swimming pools, smoke, or smog.

Pink eye is usually very easy to treat, but your treatment will largely depend on the underlying cause.

Caused by bacteria

Antibiotics are the standard treatment for pink eye caused by bacteria. The antibiotics will usually come as eye drops or ointment. Make sure to follow your doctor’s instructions for using the medication. If you wear contacts, it’s a good idea to stop wearing them until your pink eye completely clears up.

Caused by a virus

There’s no specific treatment for viral conjunctivitis. Symptoms will probably go away on their own in four to seven days, after the virus has run its course. In the meantime, you can try applying a warm compress to the eyes to help soothe your symptoms.

Caused by allergies

Over-the-counter (OTC) antihistamines can help with the inflammation caused by allergies. Loratadine (Claritin) and diphenhydramine (Benadryl) are some examples. You can also try OTC antihistamine eyedrops or anti-inflammatory eyedrops.

Caused by chemicals or irritants

Pink eye caused by chemicals or irritants will likely go away without treatment in a few days. You should make sure to rinse the eyes with sterile saline or artificial tear eyedrops to ensure the irritant has been removed. A warm compress with your eye closed may help soothe the irritation.

Viral and bacterial pink eye are highly contagious. Practicing good hygiene is one of the best ways to avoid these types of pink eye.

Here are some tips to avoid the spread of contagious pink eye:

  • wash your hands often
  • avoid rubbing your eyes
  • don’t share makeup, especially eyeline or mascara
  • use clean tissues and towels to wipe your face and eyes
  • wash and change your pillowcases frequently

If you wear contact lenses:

  • clean and replace your contact lenses often
  • avoid poorly fitted contact lenses
  • don’t share contact lenses
  • wash your hands before inserting or removing contact lenses

You can prevent allergic pink eye by avoiding whatever you’re allergic to, if possible. For example, if you’re allergic to cat dander, you can avoid petting a cat or touching anything that has made contact with a cat.

For outdoor allergies, you can close windows when the pollen count is high or use an indoor air purifier. Taking an allergy medicine daily, like Claritin or Zyrtec, at the start of allergy season can also prevent or reduce your allergy symptoms.

If you have a yellow-green discharge coming from one or both eyes or a crust in your eyes when you wake up in the morning, see a doctor. This is most likely bacterial pink eye. You’ll need a prescription for antibiotic eye drops to help clear up the infection.

You should also consider seeing a doctor if your symptoms don’t clear up in about 7 to 10 days.

There are some eye symptoms that could indicate something more serious than conjunctivitis. See a doctor if you’re experiencing:

  • blurred vision
  • reduced vision
  • intense pain in the eyes
  • sensitivity to light (photosensitivity)
  • inability to open the eye
  • the cornea becomes opaque rather than clear

See a doctor right away if you have a newborn baby with symptoms of pink eye. Conjunctivitis in babies can be very serious. You should also see a doctor you have a compromised immune system or another eye condition.

If you suspect that your child or toddler has pink eye, don’t send them to school or daycare and see a doctor as soon as possible. If the pink eye is caused by a virus or bacterial infection, it’s a good idea to keep them away from other children to avoid spreading this highly contagious infection.

Pink eye can be caused by a bacterial or viral infection, as well as allergies and other irritants. It can be hard to tell the difference sometimes, but taking a look at your symptoms and medical history can help you determine which one you have.