Pink eye (conjunctivitis): types, treatment, and when it is contagious

You usually cannot tell for sure at home, but the pattern gives strong hints. Viral conjunctivitis, the most common kind, typically starts in one eye and spreads to the other within days, produces watery discharge, and often comes with a cold or sore throat. Bacterial conjunctivitis more often stays in one eye and produces thick yellow-green pus that crusts the lashes shut overnight. Allergic conjunctivitis hits both eyes at once with intense itching, watery discharge, and a seasonal or exposure pattern. The discharge texture is the classic divider: watery points viral, thick pus points bacterial, itchy and watery in both eyes points allergic. When the picture is unclear, a clinician looks at the eye directly, and that is the right call for infants, contact lens wearers, or anything severe.

Viral and bacterial pink eye are contagious as long as symptoms are present, which is typically 3 to 7 days for viral and up to two weeks in some cases. Viral conjunctivitis spreads easily while the eye is red and watering, and the viruses causing it can live on surfaces for hours. Bacterial conjunctivitis stays contagious until about 24 hours after starting antibiotic drops, or until the discharge stops if untreated. Allergic pink eye is not contagious at all. The practical rules while contagious: wash hands constantly, do not touch your eyes, do not share towels, pillowcases, or eye makeup, and stay home from school or work while symptoms are active if you can, since pink eye spreads fast in classrooms and offices.

Usually not. Most pink eye is viral, and antibiotics do nothing for viruses; viral conjunctivitis clears on its own in one to two weeks. Even bacterial conjunctivitis often resolves without treatment in healthy adults, though antibiotic eye drops can shorten it by a few days and reduce contagiousness. Guidelines recommend antibiotics mainly for bacterial cases with thick discharge, for contact lens wearers (where the bacteria can be more aggressive), for infants, and for people with weakened immune systems. Antibiotic drops do not help allergic pink eye either; that responds to antihistamine drops and avoiding the trigger. The useful question is not whether to get drops but which type you have, and a short consult can usually sort that out.

No. Stop wearing contacts the moment symptoms start and do not put them back until the eye has been completely clear for at least 24 hours, or longer if a clinician says so. Throw away the lenses and case you were using when symptoms began, since they carry the virus or bacteria and can reinfect you; switch to a fresh pair after recovery. Contact lens wearers get a special warning for a reason: certain bacterial infections, especially pseudomonas, can scar the cornea within days, and lens wear is the biggest risk factor. If you wear contacts and have a red, painful, light-sensitive eye, that combination is same-day care, not watchful waiting. Glasses are your friend until the eye is fully healed.

Most pink eye is mild, but certain features mean same-day or emergency care: significant eye pain rather than mild irritation, sensitivity to light, blurred or reduced vision that does not clear with blinking, intense redness, or a feeling that something is stuck in the eye. Also get seen quickly for pink eye in a newborn, in anyone with a weakened immune system, after an eye injury or chemical exposure, or in contact lens wearers with pain. Those patterns raise the possibility of corneal infection, glaucoma, or inflammation inside the eye, none of which are conjunctivitis and all of which can threaten vision. Ordinary pink eye, by contrast, is itchy, gritty, red, and goopy but not truly painful, and vision stays normal.

For viral and mild cases, home care is the treatment. Clean the discharge away with a clean, wet cloth, using a fresh part of the cloth for each wipe and a separate cloth for each eye. Cool compresses soothe viral and allergic pink eye; warm compresses loosen the crusting of bacterial pink eye. Lubricating artificial tears ease the gritty feeling; skip redness-reducing drops, which can worsen things. For allergic pink eye, over-the-counter antihistamine eye drops work well, and cold compresses plus avoiding the allergen do the rest. Wash hands before and after touching the eye area, do not share towels or pillows, and wash pillowcases in hot water. If symptoms are not clearly improving after several days, or they worsen, that is the point to get checked.