Overview
Conjunctivitis, commonly called pink eye, is inflammation of the conjunctiva, the thin, clear tissue lining the eyelid and covering the white part of the eye, most often caused by viruses, bacteria, allergens, or irritants.
Disease Summary
- Category
- Infectious Disease
- Cause
- Viruses, bacteria, allergens, or irritants affecting the conjunctiva
- Transmission
- Viral and bacterial conjunctivitis spread easily through direct or indirect contact with eye discharge; allergic and irritant conjunctivitis are not contagious
- Body System
- Eyes
- Preventable
- Yes
- Curable
- Yes
Symptoms
Common Symptoms
Symptoms of conjunctivitis can vary depending on the underlying cause.
Redness
The white of the eye appears pink or red due to visible blood vessels.
Watery or Thick Discharge
Eyes may produce watery tears or thicker discharge, depending on the cause.
Itching or Irritation
A gritty or itchy feeling in the eye is common, especially with allergic conjunctivitis.
Swollen Eyelids
Mild swelling of the eyelids can accompany the irritation.
Danger Signs
Seek prompt medical attention if any of the following develop.
Moderate to Severe Eye Pain
Pain beyond mild discomfort is not typical of ordinary pink eye and needs evaluation.
Sensitivity to Light
Light sensitivity combined with eye symptoms may indicate a more serious eye condition.
Blurred Vision
Any change in vision should be assessed promptly by a healthcare provider.
Symptoms Not Improving
Worsening symptoms, or bacterial pink eye that doesn’t improve after 24 hours of antibiotics, needs medical reassessment.
Diagnosis
Clinical Assessment
Diagnosis is usually made by examining the eye and reviewing recent exposures, allergies, or contact lens use.
Symptom Pattern Review
The type and pattern of discharge, along with whether one or both eyes are affected, can help suggest the likely cause.
Laboratory Testing
In select cases, a sample of eye discharge may be tested to identify the specific virus or bacteria involved.
Laboratory Tests
Conjunctival Swab (Culture)
Identifies the specific bacteria causing infection when the diagnosis is unclear or symptoms are severe.
Viral PCR Testing
Can confirm a viral cause in select or research settings, though it is not routinely needed.
Microscopic Examination
Can help distinguish between infectious and allergic causes of conjunctivitis.
Treatment
Supportive Care
Most cases of viral and mild conjunctivitis improve on their own with cool compresses and artificial tears.
Topical Antibiotics
Used for confirmed or suspected bacterial conjunctivitis to shorten the infection and reduce spread.
Prevention
Wash hands frequently
Regular handwashing, especially after touching the eyes, reduces the spread of infectious conjunctivitis.
Avoid touching or rubbing the eyes
Reduces the chance of introducing or spreading germs.
Do not share personal items
Avoid sharing towels, makeup, or contact lenses, since these can spread infection.
Clean contact lenses properly
Following proper contact lens hygiene lowers the risk of bacterial conjunctivitis.
Risk Factors
High Risk
These factors substantially increase the likelihood of developing conjunctivitis.
- Close contact with someone who has viral or bacterial conjunctivitis
- Contact lens wear, especially with poor hygiene
- Exposure to allergens such as pollen or pet dander
Increased Risk
These factors are associated with a moderately higher risk of conjunctivitis.
- Attending schools or childcare settings
- Weakened immune system
- Recent upper respiratory infection
Additional Contributing Factors
Other factors linked with an increased likelihood of conjunctivitis.
- Exposure to irritants such as smoke or chlorine
- Seasonal allergy triggers
- Pre-existing eye conditions
Complications
Corneal Involvement (Keratitis)
In some cases, infection can spread to the cornea, which can affect vision if untreated.
Recurrent Infection
Contact lens wearers with bacterial conjunctivitis have a higher risk of related complications.
Spread to Others
Viral and bacterial conjunctivitis spread easily and can affect family members, classmates, or coworkers.
When to Seek Medical Care
Moderate to Severe Eye Pain
Should be evaluated promptly, since it is not typical of ordinary pink eye.
Vision Changes
Blurred vision or other vision changes need urgent assessment.
Symptoms Not Improving with Treatment
Bacterial pink eye that does not improve after 24 hours of antibiotics needs reassessment.
Weakened Immune System
People with conditions like HIV or those undergoing cancer treatment should seek care promptly for pink eye symptoms.
Prognosis
Usually Resolves Without Complications
Most cases of conjunctivitis, especially viral and allergic types, clear up on their own or with simple treatment.
Faster Recovery with Appropriate Treatment
Bacterial conjunctivitis often improves more quickly once antibiotic treatment begins.
Possible Recurrence with Ongoing Exposure
Allergic conjunctivitis can recur whenever a person is exposed to the triggering allergen.
Differential Diagnosis
Keratitis
Inflammation of the cornea itself, which can cause more severe pain and vision changes than typical conjunctivitis.
Uveitis
Inflammation inside the eye that can cause redness and light sensitivity, requiring urgent specialist evaluation.
Blepharitis
Inflammation of the eyelids that can cause irritation and redness similar to conjunctivitis.
Dry Eye Syndrome
Can cause redness, irritation, and discomfort resembling mild conjunctivitis.
References
Centers for Disease Control and Prevention (CDC)
CDC guidance on the causes, symptoms, spread, and prevention of pink eye.
Centers for Disease Control and Prevention (CDC), Clinical Overview
CDC clinical guidance on diagnosing and treating conjunctivitis.
Centers for Disease Control and Prevention (CDC), Treatment
CDC guidance on treatment options for viral, bacterial, and allergic conjunctivitis.
Frequently Asked Questions
Is pink eye contagious?
Viral and bacterial pink eye are very contagious, while allergic and irritant pink eye are not.
Do I need antibiotics for pink eye?
Not always. Many cases, especially viral ones, resolve on their own without antibiotics.
Can I still go to work or school with pink eye?
It is generally best to stay home if you have viral or bacterial pink eye with symptoms of illness, especially if you cannot avoid close contact with others, to avoid spreading it.
How long does pink eye usually last?
Most cases improve within one to two weeks, though bacterial conjunctivitis often clears faster with antibiotic treatment.