Bacterial Conjunctivitis

What bacterial conjunctivitis is

The conjunctiva normally keeps the eye moist and protected. When bacteria infect it, the tiny blood vessels widen, making the eye red, and white blood cells fight the infection, producing pus. It often starts in one eye and spreads to the other within a day or two.

Bacterial conjunctivitis is less common than viral conjunctivitis in adults, but more common in children. It frequently comes with an ear infection in young children (conjunctivitis-otitis syndrome), usually caused by Haemophilus influenzae.

Symptoms

• a red or pink eye
• thick yellow, white or green discharge that continues through the day
• eyelids crusted and stuck together on waking
• a gritty or sandy feeling
• mild swelling of the eyelids
• mild blurring from discharge that clears with blinking

Severe pain, marked light sensitivity and vision that does not clear with blinking are not typical and suggest a more serious eye problem.

Bacterial vs viral vs allergic conjunctivitis

Causes and how it spreads

Common bacteria include Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis. Spread occurs through:

• touching the eyes with unwashed hands
• sharing towels, pillowcases, eye makeup or eye drops
• close contact in daycare and schools
• contaminated contact lenses or cases

Special forms:

• Gonococcal conjunctivitis: from Neisseria gonorrhoeae, with very heavy, rapidly returning discharge. It can damage the cornea within days and needs urgent antibiotic injections
• Chlamydial conjunctivitis: a persistent, low-grade red eye in sexually active adults, often with no genital symptoms. Needs oral antibiotics
• Neonatal conjunctivitis: in newborns, from bacteria acquired during birth. Needs same-day assessment

Diagnosis

Most cases are diagnosed by examining the eyes and hearing the symptoms. A doctor will check vision, look at the discharge, eyelids and cornea, often using fluorescein dye to look for scratches or ulcers. A swab for culture is taken in newborns, severe or recurrent cases, contact lens wearers with ulcers, and suspected gonococcal or chlamydial infection.

Treatment

Antibiotic eye drops or ointment

Antibiotics shorten bacterial conjunctivitis, reduce spread and help children return to school sooner. Common choices include polymyxin B with trimethoprim drops, erythromycin ointment, and fluoroquinolone drops for contact lens wearers. Use them for the full course, usually 5 to 7 days, even if the eye looks better.

Ointments blur vision briefly and are often easier to use in young children. To apply drops, tilt the head back, pull the lower lid down, and place the drop in the pocket without touching the eye with the bottle.

Self-care

• clean discharge with cotton pads or a clean cloth moistened with warm water, wiping from the inner corner outward, using a fresh pad for each eye
• use cool or warm compresses for comfort
• use lubricating eye drops (artificial tears)
• stop wearing contact lenses until the eye is completely better, and throw away disposable lenses and the case used during the infection
• do not wear eye makeup, and replace eye makeup used before the infection

Is bacterial conjunctivitis contagious?

Yes. To limit spread:

• wash hands often, especially after touching the eyes
• do not share towels, pillows, washcloths or eye drops
• change pillowcases daily
• children can usually return to school or daycare 24 hours after starting antibiotics, or once discharge has stopped, depending on local policy

Complications

Complications are uncommon in otherwise healthy people but include:

• corneal ulcer (bacterial keratitis), especially in contact lens wearers
• spread of infection to the eyelid and skin around the eye (periorbital cellulitis)
• vision damage from gonococcal or neonatal infection if not treated quickly

Frequently asked questions

How do I know if my pink eye is bacterial?

Bacterial pink eye usually produces thick yellow, white or green discharge throughout the day, and the eyelids are often glued shut in the morning. Viral pink eye has watery discharge and often comes with a cold. Allergic pink eye causes intense itching in both eyes.

How long is bacterial conjunctivitis contagious?

It is contagious while there is discharge, and until about 24 hours after starting antibiotic drops or ointment. Wash hands often and avoid sharing towels and pillows during this time.

Does bacterial conjunctivitis go away without antibiotics?

Mild cases often clear on their own within 7 to 10 days. Antibiotic drops shorten the illness by a few days, reduce spread, and are usually needed for children to return to daycare. Severe cases and contact lens wearers should always be treated.

Can adults get bacterial conjunctivitis?

Yes, although it is more common in children. In adults, consider chlamydia or gonorrhea if symptoms persist despite standard drops or come with genital symptoms, and corneal infection in contact lens wearers.

Can I wear contact lenses with pink eye?

No. Stop wearing contact lenses until the eye has fully healed and you have finished treatment. Throw away disposable lenses and the case used during the infection, and see an eye doctor if you have pain or blurred vision.