Why are your eyes red?

For the past several days, you’ve had a sore throat and nasal congestion. When you woke up this morning, you noticed that your right eye had crusted over, so you couldn’t open it. After gently removing the crust, you realize that your eye is very red compared to the other one. Oh no, do you have pink eye? If so, what can you do to get rid of it? How do you prevent it from spreading to your other eye?


Pink eye, or conjunctivitis, is when the transparent membrane (conjunctiva) that lines your eyelid and covers the white part of your eyeball becomes inflamed. The inflammation causes the small blood vessels to become inflamed, making them more visible, resulting in your eye appearing reddish or pink. Common pink eye causes include viruses, bacteria, allergies, chemical splash, a foreign object in the eye, and a blocked tear duct (newborns).

Regardless of the cause, symptoms are pretty much the same. Symptoms can include redness, itchiness, a gritty feeling, tearing, and discharge that forms a crust during the night that may prevent your eye or eyes from opening in the morning. One or both eyes may be affected. Typically, symptoms will gradually clear up on their own.

Most often, pink eye is caused by adenovirus but can also result from other viruses, such as the herpes simplex virus, varicella-zoster virus, or even Covid-19. Either viral or bacterial conjunctivitis can occur along with colds or symptoms of a respiratory infection. If you wear contact lenses that aren’t cleaned properly or aren’t your own, you can end up with bacterial conjunctivitis. Both types are very contagious and are spread through direct or indirect contact with the liquid that drains from the eye of someone who’s infected.

Allergic conjunctivitis usually affects both eyes at the same time. It’s a response to an allergy-causing substance, like pollen. When your body encounters allergens, it produces an antibody, immunoglobulin E (IgE), that triggers special cells called mast cells in the mucous lining of your eyes and airways to release inflammatory substances (histamines). This results in several allergy symptoms, including red or pink eyes. If you have allergic conjunctivitis, you may experience intense itching, tearing, and inflammation of the eyes — as well as sneezing and watery nasal discharge.

Pink eye can also come from irritation from a chemical splash or foreign object in your eye. Sometimes, when trying to get rid of the chemical or object, the flushing and cleaning of your eye causes redness and irritation. Other symptoms may include watery eyes and a mucous discharge. They usually clear up on their own within about a day. If the initial flushing doesn’t get rid of the symptoms, or if the chemical is a caustic one (ex. lye), you need to be seen by your doctor or eye specialist as soon as possible. Otherwise, you could have permanent eye damage. Another reason your symptoms persistent is that you still have a foreign body in your eye or a scratch over the cornea or the covering of the eyeball (sclera).


The main goal of treating pink eye is to provide relief of symptoms. Since viruses cause most cases of conjunctivitis, antibiotics don’t help because they only work on bacteria. Instead, you can try over-the-counter eye drops, such as artificial tears. It’s also helpful to clean your eyelids with a damp cloth and apply warm or cold compresses several times a day. If you wear contact lenses, you should stop wearing them until the infection is gone. If you have disposable lens, you should throw out the contacts you’ve worn. For hard lens, you should disinfect them overnight before you reuse them. If the herpes simplex virus causes your pink eye, your doctor may recommend prescription antiviral medication.

If you have allergic conjunctivitis, you can try over-the-counter eye drops containing antihistamines and anti-inflammatory medications. Ask your doctor or pharmacist if you’re unsure which product to use. Your doctor can also prescribe one of many different types of eye drops for people with allergies. These can include medications that help control allergic reactions (ex. antihistamines and mast cell stabilizers) or help control inflammation (ex. decongestants, steroids, and anti-inflammatory eye drops). Whenever possible, try to avoid whatever is causing your allergies.


There are several things you can do to prevent the spread of pink eye. Remember, even though pink eye is contagious, it’s not anymore so than the common cold, so good hygiene practices are essential. This means you don’t touch your eyes with your hands, and be sure to wash your hands often. Always use a clean towel and washcloth daily. Also, don’t share towels or washcloths with others, especially when you have pink eye. It’s a good idea to change your pillowcases frequently. Another thing you shouldn’t share are eye cosmetics and personal eye care items (ex. contact lenses). If you develop a pink eye infection, throw away your eye cosmetics, like mascara, to prevent being reinfected in the future.

For newborns, their eyes are susceptible to bacteria normally present in the mother’s birth canal. It can cause infants to develop a serious form of conjunctivitis (ophthalmia neonatorum) in rare cases. This needs prompt treatment so they don’t end up blind. Shortly after birth, an antibiotic ointment is applied to every newborn’s eyes to prevent this.

Pink eye isn’t fun to have, but it’ll go away with the correct treatment and some time. If you have any questions or concerns about pink eye, please speak with your doctor. If you would like more information, please visit the American Academy of Ophthalmology’s Conjunctivitis page at https://www.aao.org/eye-health/diseases/pink-eye-conjunctivitis