Winter in Shanghai means you’re inside a lot, spending much of your time in smoky bars and restaurants. Bacteria and allergy-provoking agents can lead to conjunctivitis, which is highly infectious and hellishly irritating. Weepy, crusty eyes are annoying and unsightly, and the constant itch is intolerable. Desperate to know how to get rid of (and avoid) this curse, we sought the advice of Dr. Andrea Sonntag, an ophthalmologist from ParkwayHealth.

“Pink eye, or conjunctivitis, is an inflammation or infection of the transparent membrane that lines your eyelid and part of your eyeball,” she explains. “Inflammation causes small blood vessels in the conjunctiva to become more prominent, which is what causes the pink or red cast to the whites of your eyes.”

There are three types of conjunctivitis. Allergic conjunctivitis is caused by allergens in the air which trigger the production of histamines in the eye, leading to inflammation and redness. This is accompanied by insatiable itchiness and watery discharge. Bacterial conjunctivitis is characterized by thick, yellowish discharge, while the viral strain causes a more watery fluid to be released.

When faced with the itch, many people try to wait it out, but failing to seek medical help can be dangerous, according to Dr. Sonntag: “In both children and adults, pink eye can cause inflammation in the cornea that can affect vision.”

To assess the situation, your doctor will take a sample of discharge from your eyes. Allergic conjunctivitis is the easiest out of the three to treat, and is cured by antihistamines, decongestants and anti-inflammatory drops.

For bacterial pink eye, you’ll be given antibiotic eye drops. Children are usually prescribed ointment instead, which is easier to administer. It’s essential to complete the course of antibiotics. Sufferers of viral conjunctivitis just have to wait for the infection to clear up on its own.

To relieve some pain, try a lint-free cloth soaked in cold water (allergic) or warm water (bacterial and viral) and pressed to the eyes. Contact lenses should not be worn, and eye drops can help with itching.

To lower your chances of contracting pink eye, Dr. Sonntag says, “Don’t touch your eyes, and do wash your hands often. Use a fresh washcloth every day, and never share used towels. Change your pillowcases frequently and keep eye makeup to yourself.”