Bacterial Conjunctivitis: Symptoms, Diagnosis, and Treatment

Medically Reviewed By Ryan Corte, OD
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Conjunctivitis is an eye condition commonly known as “pink eye.” One cause of conjunctivitis is a bacterial infection. It is very contagious. Conjunctivitis is inflammation of the conjunctiva. This is a clear membrane, composed of different cells, that covers the inside of the eyelids and the white part of the eye. Conjunctivitis is often called “pink eye” due to the eye redness it causes.

Depending on the cause, conjunctivitis can be uncomfortable and highly contagious. The three main causes of conjunctivitis are bacterial and viral infections and allergies. Treatment is not always necessary but can reduce symptoms and how long the infection lasts.

Read on to learn more about bacterial conjunctivitis.

What is bacterial conjunctivitis?

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Bacterial conjunctivitis is a bacterial infection of the conjunctiva. It occurs when bacteria multiply in the conjunctiva and cause inflammation.

Bacterial conjunctivitis is less common than viral or allergic conjunctivitis but is more likely to cause complications and be more difficult to treat.

Acute bacterial conjunctivitis is the most common form of bacterial conjunctivitis, according to the Centers for Disease Control and Prevention (CDC). It develops quickly and usually goes away in 1–2 weeks.

What bacteria cause conjunctivitis?

Bacteria that cause most cases of bacterial conjunctivitis include:

  • Streptococcus species (strep)
  • Haemophilus influenzae
  • Moraxella catarrhalis
  • Staphylococcus aureus

Bacterial conjunctivitis can develop in infants after vaginal birth to mothers with chlamydia or gonorrhea.

How does bacterial conjunctivitis spread?

Transmission of bacterial conjunctivitis happens in the following ways:

  • Hand to eye: Bacteria on your hands spread to the eye by rubbing or touching the eye.
  • Droplet: Someone carrying bacteria coughs or sneezes, and bacteria enter the eyes.
  • Fomite: Bacteria present on a washcloth or other object may enter the eyes.
  • Mother to infant: If the mother has chlamydia or gonorrhea, bacteria from the vaginal canal may enter the infant’s eyes during vaginal delivery.

The chances of bacterial conjunctivitis increase if you have reduced immune system function or wear contact lenses.

What are the symptoms of bacterial conjunctivitis?

Symptoms of bacterial conjunctivitis include:

  • eye redness
  • eye discharge that may be thick and yellow or green
  • eyelid or eyelash crustiness from dried discharge
  • gritty or irritated sensation
  • itchiness, although this is more common with allergic conjunctivitis

When to see a doctor

Conjunctivitis is the most common cause of eye-related visits to primary care physicians. Contact an eye care professional if you have any of the following symptoms or situations along with pink eye:

Contact your doctor if pink eye symptoms do not improve after 2–3 days with or without treatment.

A physician should see an infant with symptoms of conjunctivitis as soon as possible to determine the cause. With newborn conjunctivitis, there is a chance of corneal ulcers, blindness, and the spread of infection within the body.

Bacterial vs. viral conjunctivitis

Bacterial conjunctivitis symptoms are similar to viral or allergic conjunctivitis. However, these clinical clues indicate a bacterial infection is more likely:

  • “gluey” eyes, where the eyelids are sticky due to pus, especially in the morning
  • no history of conjunctivitis
  • lack of itching or pain
  • thick rather than watery discharge

The physician may collect a sample of eye discharge for a bacterial culture to confirm the diagnosis.

How do you treat bacterial conjunctivitis?

Doctors often prescribe antibiotics for bacterial infections. However, they may not prescribe antibiotics for uncomplicated bacterial conjunctivitis, such as due to strep or H. influenzae. Contact a doctor for an accurate diagnosis. An eye examination and medical history review should guide your care.

The CDC advises antibiotic treatment for bacterial conjunctivitis due to:

  • gonorrhea
  • chlamydia
  • Neisseria meningitidis
  • Staphylococcus aureus

Bacterial conjunctivitis treatment guidelines suggest careful selection of antibiotics. Prescription bacterial conjunctivitis eye drops and ointments include but are not limited to:

  • polymyxin B/trimethoprim (Polytrim)
  • ciprofloxacin ophthalmic (Ciloxan) and other fluoroquinolone antibiotics

Doctors prescribe antibiotic pills for gonorrhea or chlamydia.

Using bacterial conjunctivitis eye drops

Some people are anxious or afraid of using eye drops. Getting children to tolerate them can also be challenging. From the American Academy of Ophthalmology (AAO), ways to help with this include:

  • Keep the drops in the refrigerator so they are cold. This will help you feel whether the drops have gone into your eyes.
  • Be honest with children — eye drops may sting a bit.
  • Ask your doctor for a dispensing device that will help if you have bad aim and miss your eyes.
  • Close your eye (or have your child close their eye) and place the drops in the inner corner of the eye. Then gently open the eye to allow drops to flow in.
  • Apply drops during naptime or at night if your child sleeps soundly.
  • Swaddle or restrain small children.

As the AAO explains, each drop contains approximately 10 times the amount of medication that will fit in the eye. So, do not worry if you feel that most of the medication is escaping down your cheek.

Self-care for bacterial conjunctivitis

Things you can do at home include:

  • Gently wipe your affected eye(s) several times daily with a new cotton ball or clean washcloth soaked in warm water. Throw away the cotton ball after a single use, and do not use the same cotton ball for both eyes.
  • Avoid swimming in pools.
  • Wash bedding, washcloths, and towels frequently in hot water.
  • When cleaning and drying eyeglasses, avoid using hand towels that others may use.
  • Do not wear contact lenses until the infection clears.

Caution with over-the-counter (OTC) eye drops

Eye drops available over the counter (OTC) that relieve redness, such as Visine and Murine, do not kill bacteria and do not treat bacterial conjunctivitis.

It is important to keep these eye drops away from children. The active ingredient tetrahydrozoline is extremely toxic if taken internally. Even a small amount can cause a dangerously low heart rate and blood pressure or difficulty breathing.

What are the potential complications?

In general, bacterial conjunctivitis has few complications. However, infection with gonorrhea or chlamydia can result in permanent vision loss. Other complications include keratitis and corneal ulcers.

How can you prevent bacterial conjunctivitis?

The CDC suggests the following precautions to avoid catching or transmitting bacterial conjunctivitis:

  • Wash your hands frequently and thoroughly.
  • Avoid touching your eyes.
  • Avoid sharing items like makeup, contact lens solutions, eye drops, and linens.
  • If only one eye is infected, do not use the same products for both eyes.

Other frequently asked questions

Ryan Corte, O.D. reviewed the following frequently asked questions.

Is bacterial conjunctivitis contagious?

Yes, bacterial conjunctivitis can spread from:

  • hand to eye
  • droplets containing bacteria landing in your eye
  • mother to infant during vaginal delivery

What is the most common cause of bacterial conjunctivitis?

In children, the most common cause of bacterial conjunctivitis is Haemophilus influenzae. A vaccine protects against H. influenzae type b (Hib) infections. In adults, Staphylococcus aureus is the most common cause. Strep bacteria also cause it.

Can bacterial conjunctivitis go away on its own?

Yes, bacterial conjunctivitis usually improves in 2–5 days without treatment but may last 2 weeks.

Summary

Bacterial conjunctivitis is a very common condition that rarely causes serious complications. Contact your primary care doctor or an eye care professional if you have eye pain, thick drainage from your eyes, and crustiness. Doctors may prescribe antibiotics for bacterial conjunctivitis.

To prevent the spread of bacterial conjunctivitis, practice good hand hygiene, do not share personal care items, and frequently wash towels and bedding.

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Medical Reviewer: Ryan Corte, OD
Last Review Date: 2022 Aug 19
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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