Pink eye, known medically as conjunctivitis, is an inflammation of the thin, clear membrane that lines the inside of your eyelids and covers the white part of your eye. This membrane contains many tiny blood vessels, and when they become inflamed, they enlarge and become more visible, giving the eye its characteristic pink or red appearance. Pink eye is one of the most common eye conditions, and while it can look alarming, most cases resolve on their own within a few days to two weeks.
What Causes the Redness
The conjunctiva is normally transparent, so you don’t notice it. But when it’s irritated by a virus, bacteria, or allergen, blood flow to the area increases. Those tiny blood vessels swell, turning the white of your eye pink or red. This is the same basic inflammatory process that makes a scratch on your skin turn red, just happening on a much more visible surface.
Three Main Types of Pink Eye
Viral
Viral conjunctivitis is the most common form and typically starts in one eye before spreading to the other. It produces a clear, watery discharge and often comes with a gritty sensation, as if something is stuck in your eye. Your eyelids may swell, and light might feel uncomfortable. Because it’s caused by the same family of viruses responsible for the common cold, it frequently shows up alongside cold or flu symptoms like a sore throat or runny nose. There’s no medication that speeds it up. It simply runs its course over one to two weeks.
Bacterial
Bacterial pink eye stands out because of its discharge: thick, yellow or greenish, and sticky enough to glue your eyelids shut overnight. It can affect one or both eyes and causes redness, irritation, and swelling. With treatment, symptoms typically improve within a few days, though mild cases often clear up on their own. The American Academy of Ophthalmology notes that mild bacterial conjunctivitis is likely to be self-limited, and no single antibiotic eye drop has been shown to work better than another.
Allergic
Allergic conjunctivitis hits both eyes at once and is driven by allergens like pollen, dust mites, or pet dander. The hallmark symptom is intense itching, along with redness, swelling, and excessive tearing. You’ll usually have other allergy symptoms too, like sneezing or a stuffy nose. This type isn’t contagious and tends to flare up seasonally or whenever you’re exposed to your specific triggers.
How Pink Eye Spreads
Viral and bacterial pink eye are both contagious. They spread through direct contact with infected eye secretions, contaminated hands, or shared items like towels and pillowcases. You can also pick it up from touching a surface someone with pink eye has touched after rubbing their eyes. Pink eye generally remains contagious as long as there is tearing and matted discharge, which can last anywhere from a few days to two weeks depending on the type.
Allergic conjunctivitis, on the other hand, is not contagious at all since it’s an immune response to an allergen, not an infection.
How to Manage It at Home
Cold compresses and artificial tears (available over the counter) can relieve inflammation and dryness. Place a clean, cool, damp cloth over your closed eyes for a few minutes at a time. If you wear contact lenses, stop wearing them until your symptoms are completely gone. Throw away any disposable lenses and cases you used while your eyes were infected, and clean reusable lenses and eyeglasses thoroughly before using them again.
Cleaning discharge from around your eyes several times a day helps with comfort. Use a clean, wet washcloth or a fresh cotton ball each time, and throw away cotton balls after a single use. Wash used washcloths in hot water and detergent.
Preventing the Spread
If you or someone in your household has pink eye, a few habits make a big difference:
- Wash your hands frequently with soap and water for at least 20 seconds, especially before and after touching your eyes or applying eye drops. If soap isn’t available, use hand sanitizer with at least 60% alcohol.
- Don’t touch or rub your eyes with your fingers.
- Don’t share personal items like pillows, towels, washcloths, eye drops, makeup, makeup brushes, or eyeglasses.
- Wash bedding and towels often in hot water and detergent.
- Keep eye drop bottles separate for your infected and non-infected eyes.
- Avoid swimming pools until the infection has cleared.
When Children Get Pink Eye
Pink eye is extremely common in kids, partly because they touch their faces frequently and share supplies in classrooms and daycares. In children, bacterial conjunctivitis is commonly caused by different bacteria than in adults, and the thick discharge can be especially heavy.
The CDC recommends that children with viral or bacterial conjunctivitis stay home from school if they have systemic signs of illness or can’t avoid close contact with classmates. They can return once a clinician approves and any prescribed treatment has been started. Many schools have their own policies, so it’s worth checking with yours.
Symptoms That Need Prompt Attention
Most pink eye is uncomfortable but harmless. However, some symptoms signal something more serious. See a healthcare provider if you experience eye pain (not just irritation), sensitivity to light, blurred vision, or intense redness that isn’t improving. These can indicate a deeper infection, a corneal problem, or another condition that looks like pink eye but requires different treatment.
One rare but serious form of bacterial conjunctivitis, caused by the bacteria responsible for gonorrhea, progresses rapidly and can threaten vision. It produces a sudden, severe discharge and requires immediate treatment, not just eye drops but systemic antibiotics.