Pink eye is an inflammation of the conjunctiva, the thin transparent membrane that lines the inside of your eyelids and covers the white part of your eye. When this tissue gets irritated or infected, the tiny blood vessels inside it swell and become more visible, giving the eye its characteristic pink or red appearance. The most common cause is a viral infection, followed by bacterial infections and allergies.
The Four Types of Pink Eye
Not all pink eye is the same. The cause determines how it feels, how it spreads, and how it’s treated.
Viral pink eye is the most common form. It typically shows up alongside or shortly after a cold or upper respiratory infection. Your eyes will feel itchy and watery, producing a thin, clear discharge rather than thick gunk. It often starts in one eye and spreads to the other within a day or two. The lymph node in front of your ear may feel swollen and tender.
Bacterial pink eye produces a thicker, white-yellow discharge that can crust your eyelids shut overnight. You may wake up with your lashes matted together. It often feels like something is stuck in your eye. In children, the bacteria responsible are commonly the same ones that cause ear infections and sinus infections. In adults, staph bacteria are a frequent culprit.
Allergic pink eye hits both eyes at once and causes intense itching and burning along with puffy eyelids. The discharge is watery, not thick. If your symptoms flare every spring and summer, pollen and grass are likely triggers. If they persist year-round, indoor allergens like dust mites, pet dander, or mold are more probable. This type is not contagious.
Irritant pink eye results from a chemical splash, chlorine in a pool, a foreign object, or even prolonged contact lens wear. It causes redness and discomfort but clears up once the irritant is removed. This type is also not contagious.
How Pink Eye Spreads
Viral and bacterial pink eye spread easily. The CDC identifies three main transmission routes: direct personal contact like touching or shaking hands with an infected person, airborne droplets from a cough or sneeze, and touching contaminated surfaces then rubbing your eyes. That last one is the big one. Doorknobs, shared towels, pillowcases, and phones can all carry the virus or bacteria. If you touch a contaminated surface and then touch your face before washing your hands, you’ve given the infection a direct path to your eye.
Children spread pink eye so efficiently in schools and daycares because they touch their eyes constantly, share toys, and aren’t great about handwashing. Adults most often pick it up from a sick household member or by touching their own eyes after contact with respiratory secretions, since viral pink eye is frequently caused by the same viruses behind the common cold.
Newborns and Pink Eye
Babies can develop pink eye within their first four weeks of life, a condition called ophthalmia neonatorum. It’s typically acquired during delivery. Chlamydia is the most common infectious cause in the United States, responsible for 2% to 40% of newborn cases. Gonorrheal pink eye in newborns is rarer (less than 1% of cases) but is considered a medical emergency because it can damage the cornea rapidly. Risk factors include maternal sexually transmitted infections, premature rupture of membranes, and poor prenatal care. Hospitals routinely apply antibiotic ointment to newborns’ eyes as a preventive measure, though this does not reliably prevent chlamydial infections.
How to Tell Which Type You Have
The discharge from your eye is the most useful clue. Thick, yellow or greenish goo that mats your lashes together overnight points toward a bacterial infection. Thin, watery, clear discharge, especially if you recently had a cold, suggests a virus. Watery discharge with intense itching in both eyes and a known history of allergies points toward allergic conjunctivitis.
Viral pink eye also tends to make the small lymph node just in front of your ear swell and feel tender to the touch. Bacterial pink eye rarely does this, and allergic pink eye never does. These aren’t perfect rules, and overlap exists, but they can help you have a more informed conversation with a healthcare provider if symptoms don’t resolve on their own.
How Long You Stay Contagious
Viral and bacterial pink eye remain contagious as long as the eye is producing discharge and tearing. For bacterial pink eye, antibiotic drops typically shorten that window. Most schools and daycares allow children to return once symptoms have clearly improved, there’s no fever, and the child can avoid touching their eyes and practice good hand hygiene. Children who can’t reliably keep their hands away from their eyes should stay home until the discharge stops entirely.
Viral pink eye can linger longer since antibiotics don’t help it. You may be contagious for up to two weeks in some cases, though the highest-risk period is while your eyes are visibly red and watery.
Contact Lenses, Makeup, and Prevention
If you develop pink eye while wearing contacts, stop wearing them immediately and don’t resume until your symptoms are completely gone. Throw away any disposable lenses and lens cases you used while infected. Extended-wear or reusable lenses need thorough cleaning and disinfection before you use them again.
The same goes for eye makeup. Mascara, eyeliner, and brushes that touched your eyes during the infection can harbor bacteria or viruses. Replace them. Don’t share eye makeup, contact lenses, or eyeglasses with anyone, even when you’re healthy.
The single most effective prevention strategy is washing your hands frequently and keeping them away from your eyes. If someone in your household has pink eye, give them their own towels and washcloths, wash pillowcases often, and disinfect commonly touched surfaces.
Symptoms That Need Prompt Attention
Most pink eye is uncomfortable but harmless and resolves within one to two weeks. Certain symptoms, however, can signal something more serious. Significant eye pain (not just irritation), blurred vision or decreased vision, severe sensitivity to light, a feeling that something is stuck in your eye that doesn’t go away, or worsening symptoms after several days all warrant a prompt visit to a healthcare provider. These can indicate a corneal infection, a deeper inflammatory condition, or another eye problem that mimics pink eye but requires different treatment.