Conjunctivitis: Symptoms, Causes & Treatment

Conjunctivitis (pink eye) is inflammation of the conjunctiva, the thin membrane that covers the white part of the eye and lines the inside of the eyelids. It can cause redness, itching, pain, swelling, excessive tearing, or pus-like discharge.

This eye inflammation can affect people of any age. It is usually caused by a bacterial, viral, or fungal infection or by an allergy to substances such as dust, dust mites, or chemicals like shampoo.

Treatment for conjunctivitis depends on the cause and should be recommended by an ophthalmologist. It may include cold compresses, artificial tears, or antibiotic or corticosteroid eye drops and ointments.

Conjunctivitis symptoms

The main symptoms of conjunctivitis include:

• Redness in the affected eye

• Eyelid swelling

• Excessive tearing

• Itching

• Increased sensitivity to light

• Eye pain

• Difficulty opening the affected eye

• A gritty feeling in the eye

When conjunctivitis is caused by an infection, it may also produce pus or a thick, yellowish discharge.

Conjunctivitis can affect one or both eyes. It is important to see a primary care provider or an ophthalmologist so the cause can be identified and the most appropriate treatment can be recommended.

Online symptom checker

To assess your likelihood of having conjunctivitis, select the symptoms you are experiencing below:

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This symptom checker is only a guidance tool. It does not provide a diagnosis or replace an evaluation by an ophthalmologist.

Confirming a diagnosis

Conjunctivitis is usually diagnosed by a healthcare provider based on the symptoms, when they began, the person’s medical and allergy history, and any recent exposure to chemicals.

The provider may also perform an eye exam, which usually includes checking visual acuity and examining the eyelids, conjunctiva, cornea, eye movements, and pupil reactions. A slit-lamp examination may also be performed.

If conjunctivitis keeps returning, causes severe or pus-like discharge, does not improve with treatment, or is suspected to be caused by chlamydia or gonorrhea, the provider may collect a sample of the eye discharge. The sample can be sent to a laboratory to help identify the cause.

Possible causes

The main causes of conjunctivitis include:

• Viral, bacterial, fungal, or protozoal infections

• Allergies to dust, pollen, dust mites, mold, pollution, smoke, or cosmetic products

• Use of contaminated makeup products or applicators

• Improper cleaning of contact lenses

• Rubbing the eyes or touching them with dirty hands

• Contact with contaminated water

• Foreign objects in the eye

• An allergic reaction to eye drops or ophthalmic ointments

Eye contact with chemicals such as shampoo, conditioner, or cleaning products can also cause conjunctivitis.

Main types

Conjunctivitis can be infectious or noninfectious. The main types include:

1. Bacterial conjunctivitis

Bacterial conjunctivitis is an infectious type of conjunctivitis caused by bacteria such as Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae, Chlamydia trachomatis, or Corynebacterium diphtheriae.

These bacteria can spread through close contact with someone who has bacterial conjunctivitis, touching the eyes with dirty hands, or using contaminated makeup products or applicators.

2. Viral conjunctivitis

Viral conjunctivitis is another infectious type of conjunctivitis. It is mainly caused by adenoviruses and can spread through direct contact with the virus, respiratory droplets, or contaminated places such as swimming pools.

Other viruses that can cause this type of conjunctivitis include enteroviruses, herpes simplex virus, varicella-zoster virus, and COVID-19.

3. Fungal conjunctivitis

Fungal conjunctivitis is a rare type of infectious conjunctivitis. It may be caused by poorly cleaned contact lenses or accidental eye contact with contaminated wood or plant material.

The main fungi that can cause this type of conjunctivitis include Aspergillus species and Fusarium species.

4. Gonococcal conjunctivitis

Gonococcal conjunctivitis is an infectious type of conjunctivitis caused by Neisseria gonorrhoeae, the bacterium that causes gonorrhea, a sexually transmitted infection (STI).

This type of conjunctivitis can occur in newborns. It may be transmitted when the baby comes into contact with vaginal fluids containing the bacteria during vaginal delivery.

Gonococcal conjunctivitis may also be transmitted through direct sexual contact with infected fluids or by touching the eye with a hand contaminated with the bacteria.

5. Allergic conjunctivitis

Allergic conjunctivitis is a noninfectious type of conjunctivitis caused by allergies to substances such as dust and dust mites. It is more common during spring or when the weather is dry.

6. Irritant conjunctivitis

Irritant conjunctivitis is a noninfectious type of conjunctivitis caused by contact with substances that irritate the eyes, such as swimming pool chemicals, shampoo, cleaning products, or cosmetics.

7. Neonatal conjunctivitis

Neonatal conjunctivitis can occur during a newborn’s first month of life. It may be caused by a blocked tear duct or by an infection transmitted during vaginal delivery through contact with fluids containing viruses or bacteria.

Treatment options

Pink eye treatment depends on the underlying cause and should be recommended by a healthcare provider. Applying cold compresses to the affected eye may help reduce inflammation and swelling.

For allergic conjunctivitis, lubricating, antihistamine, or corticosteroid eye drops for pink eye may be recommended.

For bacterial conjunctivitis, a healthcare provider may prescribe antibiotic eye drops or ophthalmic ointments containing medications such as polymyxin B or moxifloxacin.

According to the CDC, gonococcal conjunctivitis in adolescents and adults is treated with a single intramuscular injection of ceftriaxone. Because this infection is uncommon and treatment data are limited, consultation with an infectious disease specialist may also be considered.

How to prevent

To help prevent conjunctivitis, it is important to:

• Avoid rubbing the eyes or touching them with dirty hands
• Wash your hands frequently and before touching your eyes
• Clean makeup products and applicators properly and do not share them
• Change bed linens at least once a week
• Clean contact lenses properly
• Use disposable tissues or compresses to clean the eyes
• Avoid contact with substances that may cause allergies

According to the CDC, avoiding close contact with others and not sharing personal items, such as towels, makeup, eye drops, or contact lens supplies, can help prevent infectious conjunctivitis from spreading.