Bacterial Conjunctivitis: Symptoms, Causes & Treatment

Bacterial conjunctivitis is an inflammation of the conjunctiva, the thin membrane that lines the white part of the eyes and the inside of the eyelids, caused by bacteria.

This inflammation may cause symptoms like redness, itching, and thick yellow discharge from the eye. The bacteria that cause bacterial conjunctivitis can spread through close contact with someone who has the infection or by using contaminated makeup brushes or accessories.

Treatment for bacterial conjunctivitis is prescribed by a primary care provider or an ophthalmologist and involves using antibiotic eye drops or ointments, along with proper eye hygiene using sterile saline solution.

In some mild cases, especially in adults, the infection can resolve on its own without antibiotics, although treatment is often prescribed to help symptoms clear more quickly and prevent transmission.

Bacterial conjunctivitis symptoms

The main symptoms of bacterial conjunctivitis include:

• Redness in the affected eye;

• Thick, yellowish or pus-like discharge;

• Excessive tearing;

• Irritation or a burning sensation in the eye;

• Itching or eye pain;

• Increased sensitivity to light;

• A gritty feeling, as if there is sand in the eye.

Symptoms can occur in one or both eyes. In some cases, there may also be mild swelling around the eyes, especially at night, or even blurred vision due to discharge.

If symptoms of bacterial conjunctivitis last for more than 2 or 3 days, it’s important to see a primary care provider or an ophthalmologist to confirm the diagnosis and start the appropriate treatment.

Possible causes

The main bacteria that cause bacterial conjunctivitis are:

• Haemophilus influenzae;

• Streptococcus pneumoniae;

• Moraxella catarrhalis;

• Staphylococcus aureus;

• Pseudomonas aeruginosa.

These bacteria cause inflammation in the conjunctiva by dilating its blood vessels, leading to symptoms.

Other bacteria, such as Neisseria gonorrhoeae and Chlamydia trachomatis, can also cause bacterial conjunctivitis, particularly in newborns. However, they can also affect sexually active adolescents or adults and are often accompanied by symptoms in the genital area.

How it spreads

In most cases, bacterial conjunctivitis develops after direct contact with an infected person, especially when hygiene is inadequate.

Other factors that can contribute to the infection include using contaminated cosmetics or makeup brushes, poor contact lense hygiene, frequent use of eye medications, or having recently undergone eye surgery.

Eye conditions such as blepharitis, dry eyes, or structural abnormalities can also increase the risk of developing bacterial conjunctivitis.

Contact lens wearers are at higher risk for infections caused by Pseudomonas aeruginosa and should remove lenses at the first sign of redness or discharge. These cases may require antibiotic drops with anti-pseudomonal coverage, such as a fluoroquinolone, and prompt medical evaluation.

Confirming a diagnosis

A primary care provider or an ophthalmologist diagnoses bacterial conjunctivitis based on an evaluation of the person’s symptoms, medical history, and an eye exam to check the conjunctiva and cornea.

In some cases, a healthcare provider may collect a sample of discharge from the eye to send to the lab for analysis in order to identify the bacteria responsible for the infection. Cultures are generally recommended for severe, recurrent, or non-responding cases, as well as for hyperacute infections and in newborns.

Bacterial conjunctivitis treatment

Treatment for bacterial conjunctivitis should always be guided by a primary care provider or an ophthalmologist and usually involves antibiotic eye drops or ointments.

Examples include ophthalmic azithromycin (AzaSite), polymyxin B with trimethoprim (Polytrim), and erythromycin ophthalmic ointment. These medications are effective against many of the bacteria that cause conjunctivitis (pink eye) and are commonly used as first-line treatments.

When bacterial conjunctivitis is caused by Neisseria gonorrhoeae or Chlamydia trachomatis, oral antibiotics are typically prescribed along with eye drops. In newborns, hospitalization may be required to receive intravenous antibiotics.

Keeping the eyes clean and free from discharge is also important. This can be done by gently wiping the eyes with a clean compress and sterile saline solution.

If the infection is not treated properly, it can spread to the cornea, leading to increased pain and vision problems. In such cases, a follow-up visit to the ophthalmologist is recommended to adjust treatment.

Care during treatment

During treatment for bacterial conjunctivitis, it’s important to follow good hygiene practices to prevent spreading the infection to others:

• Wash towels, sheets, and pillowcases daily and separately from other items;

• Wash your hands with soap and water or use an alcohol-based sanitizer before and after touching your eyes;

• Avoid hugs, kisses, and handshakes until the infection has cleared.

Children and adults can usually return to school or work once symptoms improve and they can maintain proper hygiene, as long as local policies allow.

Duration and recovery

Bacterial conjunctivitis usually lasts 10 to 14 days, even without treatment. However, once antibiotic treatment begins, symptoms typically improve within 2 to 3 days.

After this time, most people can safely return to daily activities without risking spreading the infection to others.