Depends on the type: viral and bacterial conjunctivitis are very contagious - they spread through eye secretions on hands, towels and surfaces. Allergic conjunctivitis is not contagious at all. You stay contagious while there is discharge and tearing, and for bacterial, until 24 hours after starting antibiotic drops.
How it spreads: viral and bacterial pink eye travel via eye secretions - you rub your eye, touch a doorknob, someone else touches it and rubs theirs. It is that efficient, which is why it rips through households and classrooms. The contagious window: from when symptoms start until the discharge and tearing stop - typically about a week for viral (sometimes two), and for bacterial, until 24 hours of antibiotic drops have passed. Allergic pink eye (both eyes, intensely itchy, seasonal) involves no infection and spreads to nobody. Household rules while someone has it: hand-washing constantly, no shared towels, pillowcases or eye makeup, wash pillowcases daily, and clean the uninfected eye first if you must touch them. School and work: bacterial can return after 24 hours on drops; viral when discharge settles with good hygiene; allergic immediately. Emergencies skip this list: chest pain, trouble breathing, stroke signs, severe bleeding, or thoughts of self-harm mean call 911, or 988 for a mental health crisis in the US.
What to do
Common questions
How long is pink eye contagious?
Viral: from symptom onset until the tearing and discharge resolve - usually about a week, occasionally two. Bacterial: until 24 hours after starting antibiotic eye drops (without drops, until discharge stops). Allergic: never contagious. The practical marker for all infectious cases is discharge - as long as the eye is producing it, treat the person as contagious.
Can pink eye spread to my other eye or my family?
To your other eye, easily - that is the usual course (one eye, then both within days) because people rub one then the other. To family, also easily through shared towels, pillowcases and hands. The defenses are boring and effective: wash hands every time you touch your face, dedicate towels and pillowcases to the infected person and change them daily, and throw out eye makeup that touched the infected eye.
When can my child go back to school with pink eye?
School policies vary but the common standard: bacterial conjunctivitis - after 24 hours of antibiotic drops; viral - when tearing and discharge are settling and the child can manage hygiene (many schools read the AAP position that exclusion is unnecessary once symptoms are mild, but most districts still require the discharge to stop). Allergic - no restriction. Check your district's letter; the pediatrician's note stating the type usually settles it.
How do I know which type I have?
Viral: watery discharge, often starting in one eye, usually alongside a cold. Bacterial: thick yellow-green discharge, lashes crusted together on waking. Allergic: both eyes, intense itching, watery, tracks with pollen season or pet exposure, often with sneezing. When the pattern is unclear - or you have pain, light sensitivity or vision changes - a clinician should sort it; telehealth handles most of these from symptoms and a photo. Emergencies skip this list: chest pain, trouble breathing, stroke signs, severe bleeding, or thoughts of self-harm mean call 911, or 988 for a mental health crisis in the US.