Pink eye (conjunctivitis) can be infectious or noninfectious. If you have bacterial or viral pink eye, your infection can spread to someone else. If you have allergic pink eye, you can't infect someone else.

To help prevent a viral or bacterial pink eye infection from spreading, wash your hands often and don't share tissues, towels, pillowcases, or any other personal items.

Your symptoms can help determine what kind of conjunctivitis you have:

• Allergic conjunctivitis: Redness, itchiness, and watery discharge in both eyes

• Bacterial conjunctivitis: Redness and thick discharge, usually in one eye

• Viral conjunctivitis: Redness, a gritty or sandy sensation, and watery discharge in one eye, usually followed by the other eye within 2 days. Viral pink eye is often preceded by mild cold or flu symptoms from a common adenovirus. Most adult cases of conjunctivitis are viral.

It's important for a clinician to know what's causing your pink eye so they can prescribe the right conjunctivitis treatment and provide symptom relief.

Depending on what kind of conjunctivitis you have, your clinician may prescribe antibiotic eye drops or ointments like erythromycin, ciprofloxacin, or trimethoprim-polymyxin B; allergy drops like olopatadine (Pataday) or azelastine (Optivar); or drops for dry eyes.

Please note: This information is for general reference only. Your clinician will review your symptoms and health history to determine which (if any) pink eye treatments are medically appropriate.

Though conjunctivitis (inflammation of the conjunctiva) is the most common cause of eye redness and discharge, multiple conditions can cause red or pink eyes, including the following:

• Blepharitis, when your eyelids are irritated and inflamed

• Stye (hordeolum), when you have a painful lump on the eyelid

• Subconjunctival hemorrhage, when a strain like a violent sneeze causes broken blood vessels in the eye

• Corneal abrasion, when the surface of the cornea experiences a trauma like a scratch

• Contact lens overwear, which can cause dryness or abrasions

If you sense a foreign body in your eye, can't keep your eye open, have had recent eye trauma, experience vision changes, develop light sensitivity, or feel serious eye pain, you'll need to see a trusted healthcare provider like an opthalmologist (eye doctor) or an urgent care clinician for an in-person evaluation as soon as possible.