Question: My sister has had pinkeye for the past week, and now it’s in her other eye. Is this normal?

Answer: Yes. Conjunctivitis, or pinkeye, often spreads from one eye to the other. This infection of the thin, transparent layer of tissue on the inner surface of the eyelid and white part of the eye is most often caused by a viral or bacterial infection, or an allergic reaction to irritants in the air. Conjunctivitis can last for weeks and can be highly contagious.

An optometrist can diagnose the type of conjunctivitis, but here are some clues: Bacterial conjunctivitis most often has a mucous discharge and can cause the eyelids to “seal” shut overnight. Staphylococcal or streptococcal bacteria from your own skin or respiratory system is the usual cause. Viral conjunctivitis may include a watery discharge from the eyes that can be painful. Common cold viruses that are spread by coughing and/or sneezing typically cause it. Allergic conjunctivitis causes itching and may include a runny nose and sneezing when coming into contact with the irritant.

Warm compresses on the infected eye will help soothe pain for those with bacterial or viral conjunctivitis. Cool compresses work best for the allergic condition. What to do: Soak a clean cloth in water, wring it out and apply it to the eye for about 10 minutes, two or three times a day. Antibiotic eyedrops or ointments may be prescribed for bacterial conjunctivitis but not for a viral infection. Antihistamine or topical steroid eyedrops may help allergy sufferers.

Because pinkeye can easily spread from one eye to the other, hands should be washed often and kept away from the eyes. Anyone with conjunctivitis should not share towels with others and should change his/her pillowcase and towels every day.