Pink eye, medically known as conjunctivitis, is a common eye condition characterized by inflammation or infection of the conjunctiva, the transparent membrane lining the eyelid and covering the white part of the eye1 . It affects people of all ages and can be caused by viruses, bacteria, allergens, or irritants2 . While most cases are mild and resolve on their own, pink eye can be highly contagious when caused by infectious agents, making prevention and proper treatment important3 .
Types of Conjunctivitis
Conjunctivitis is classified into three main types based on its cause: infectious, allergic, and chemical. Each type has distinct mechanisms, symptoms, and treatment approaches4 5.
Infectious Conjunctivitis
Infectious conjunctivitis results from viral or bacterial infections of the conjunctiva6 . Viral conjunctivitis accounts for the majority of infectious cases and is highly contagious7 . Adenoviruses, which also cause respiratory infections like the common cold, are the most frequent viral culprits7 . Bacterial conjunctivitis is caused by bacteria such as Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenzae8 . It can present in acute, hyperacute, or chronic forms depending on severity and duration6 .
Transmission of infectious conjunctivitis occurs through direct contact with infected secretions, contaminated objects, or close personal contact9 . Viral conjunctivitis often accompanies systemic symptoms like fever and swollen lymph nodes9 . Bacterial conjunctivitis typically produces purulent (pus-like) discharge and causes eyelid crusting, especially in children10 6.
Allergic Conjunctivitis
Allergic conjunctivitis arises from the body's immune response to environmental allergens such as pollen, dust mites, molds, or pet dander11 10. It is not contagious and often occurs seasonally, frequently coexisting with other allergic conditions like rhinitis and asthma10 . Symptoms include intense itching, watery eyes, and eyelid swelling10 . Allergic conjunctivitis can also be triggered by contact lenses or cosmetics5 .
Chemical Conjunctivitis
Chemical conjunctivitis results from irritation caused by exposure to chemicals, smoke, dust, or foreign objects1 5. Contact with noxious substances like chlorine in swimming pools or air pollution can inflame the conjunctiva1 . This type is not contagious and requires prompt removal or flushing of the irritant to prevent damage5 .
Pink Eye Symptoms
Pink eye symptoms vary depending on the cause but generally include redness and inflammation of the eye10 . The hallmark sign is dilation of blood vessels in the conjunctiva, giving the eye a pink or red appearance1 12. Common symptoms include:
- Redness in one or both eyes2
- Gritty or foreign body sensation10
- Itching or burning2
- Discharge that may be watery, stringy, or thick and purulent10 6
- Eyelid swelling and crusting, especially in bacterial infections10
- Sensitivity to light (photophobia) 10
- Tearing or watery eyes10
Viral conjunctivitis often causes watery discharge and may be accompanied by systemic symptoms such as fever and swollen lymph nodes9 . Bacterial conjunctivitis usually produces thick, yellow-green discharge that can mat the eyelids shut overnight6 . Allergic conjunctivitis is characterized by intense itching and clear, watery discharge10 .
Causes and Contagiousness of Pink Eye
Pink eye can be caused by viruses, bacteria, allergens, or irritants1 . Infectious conjunctivitis, caused by viruses or bacteria, is highly contagious and spreads easily through contact with infected secretions6 3. Allergic and chemical conjunctivitis are not contagious3 .
How Pink Eye Spreads
Infectious pink eye spreads primarily through:
- Direct hand-to-eye contact after touching contaminated surfaces or secretions9 3
- Contact with respiratory droplets from coughing or sneezing3
- Sharing personal items like towels, bedding, or eye cosmetics9 3
- Close personal contact, such as shaking hands or touching the face3
The infection often starts in one eye and can spread to the other through rubbing or touching10 . Children in group settings such as schools or daycare are at higher risk of transmission due to close contact and frequent hand-to-eye contact9 . Neonates can acquire bacterial conjunctivitis during birth from infected maternal genital secretions13 .
Viral conjunctivitis is highly contagious and can survive on surfaces for up to two weeks, making hand hygiene and avoiding eye touching critical to prevent spread14 3.
Pink Eye Pictures in Adults and Children
Pink eye presents similarly in adults and children, with visible redness and swelling of the conjunctiva and eyelids1 . The eyes may appear bloodshot with varying degrees of discharge depending on the cause6 . In bacterial cases, thick discharge and eyelid matting are common, while viral and allergic conjunctivitis usually cause watery discharge10 6. Allergic conjunctivitis often affects both eyes and is associated with seasonal patterns10 .
Children may show more pronounced eyelid swelling and purulent discharge, especially in bacterial infections6 . Neonatal conjunctivitis presents shortly after birth with eyelid redness and swelling10 .
Pink Eye in Children
Children are particularly vulnerable to pink eye due to frequent hand-to-eye contact and close interactions in group settings9 . Infectious conjunctivitis spreads rapidly among children in schools and daycare centers9 . Symptoms in children often include redness, eyelid swelling, and discharge, which may be purulent in bacterial cases10 6.
Pink Eye in Newborns
Newborns can develop a severe form of conjunctivitis called ophthalmia neonatorum, usually caused by bacteria transmitted from the mother during delivery, such as Chlamydia trachomatis or Neisseria gonorrhoeae10 1314. This condition requires immediate treatment to prevent permanent eye damage13 14. Symptoms include eyelid swelling, redness, and discharge appearing shortly after birth10 .
Diagnosing Pink Eye
Diagnosis of pink eye is primarily clinical, based on patient history and ocular examination6 15. Key diagnostic features include the type of discharge, presence of systemic symptoms, and whether one or both eyes are affected16 .
- Purulent, thick discharge suggests bacterial conjunctivitis10 6.
- Watery discharge with itching points to viral or allergic conjunctivitis10 .
- Associated symptoms like preauricular lymphadenopathy indicate viral infection15 .
- Itching and history of allergies support allergic conjunctivitis diagnosis15 .
Laboratory testing of conjunctival swabs is rarely needed but may be used in complicated or severe cases to identify the infectious agent8 15. In newborns, prompt diagnosis is critical to initiate appropriate treatment10 .
Pink eye is when there’s a certain amount of inflammation on the surface of the eye and as a result of that inflammation, you have blood vessels that become more engorged12 .
— Herbert John Ingraham, Geisinger
Pink Eye Treatment Options
Treatment depends on the underlying cause of conjunctivitis and patient characteristics17 5. Most viral and mild bacterial cases resolve without antibiotics, focusing on symptom relief and preventing spread17 6. Allergic conjunctivitis requires managing the allergic response11 .
Treatments for Viral Pink Eye
Viral conjunctivitis is usually self-limiting, resolving within 7 to 14 days, though some cases may last up to three weeks17 7. There is no specific antiviral treatment for common adenoviral conjunctivitis7 . Supportive care includes:
- Warm or cool compresses to soothe irritation10
- Artificial tears to relieve dryness and discomfort5
- Good hygiene to prevent transmission9
Topical antivirals are reserved for herpetic conjunctivitis caused by herpes simplex virus but are not effective for adenoviral infections7 .
Treatments for Bacterial Pink Eye
Mild bacterial conjunctivitis may clear spontaneously within 1 to 2 weeks17 . Antibiotics can shorten the duration, reduce complications, and prevent spread, especially in cases with significant discharge or in immunocompromised patients17 6. Common treatments include antibiotic eye drops or ointments targeting typical bacteria like Staphylococcus aureus and Streptococcus pneumoniae8 6.
Contact lens wearers should stop using lenses during infection and seek prompt evaluation to avoid complications like keratitis18 .
Treatments for Allergic Pink Eye
Managing allergic conjunctivitis focuses on avoiding allergens and relieving symptoms11 . Treatment options include:
- Antihistamine eye drops to reduce itching and inflammation11 5
- Artificial tears to flush allergens and soothe eyes5
- Cool compresses to reduce swelling and discomfort10
Severe cases may require prescription allergy medications11 .
Treatments for Pink Eye in Newborns and Babies
Neonatal conjunctivitis requires immediate medical attention due to the risk of serious complications13 14. Treatment depends on the causative agent but often involves topical and systemic antibiotics10 . Preventive antibiotic ointment is routinely applied to newborns' eyes shortly after birth to reduce infection risk14 .
Treatments for Pink Eye in Children
Treatment in children follows the same principles as adults but with special attention to preventing spread in group settings10 9. Supportive care and hygiene are emphasized, with antibiotics used for bacterial cases10 . Parents should ensure children avoid touching their eyes and practice handwashing9 .
It’s understandable to want to get rid of pink eye as quickly as possible, but people should avoid trying unproven remedies they’ve heard of on social media19 .
— Ami Vadada, American Academy of Ophthalmology
Pink Eye Prevention
Preventing pink eye, especially infectious types, relies heavily on good hygiene practices9 3. Key preventive measures include:
- Frequent handwashing with soap and water for at least 20 seconds9 3
- Avoiding touching or rubbing the eyes9
- Not sharing towels, bedding, eye cosmetics, or personal eye care items9 3
- Cleaning and disinfecting surfaces and objects that may be contaminated9
- Using disposable or freshly laundered materials to clean eye discharge9
- Contact lens hygiene and avoiding lens use during infection18
Complete prevention is challenging due to multiple transmission routes, but these measures significantly reduce risk9 .
Every so often, social media trends encourage people to put certain foods and herbal extracts in the eye as a cure, but these are not sterile and can make eye conditions much worse. Never put anything in your eye that isn't approved by a doctor19 .
— Ami Vadada, American Academy of Ophthalmology
Possible Complications
Most cases of conjunctivitis resolve without serious problems6 . However, untreated or severe bacterial conjunctivitis can lead to complications such as:
- Corneal ulcers and perforation6
- Keratitis (corneal inflammation) 6
- Permanent vision impairment in rare cases14
Persistent or worsening symptoms warrant prompt medical evaluation to prevent these outcomes17 6.
In general, that’s just a regular old virus. Most of the time it’s just the same thing that you have going on somewhere else12 .
Summary of Pink Eye
Pink eye, or conjunctivitis, is a common inflammation or infection of the eye's conjunctiva caused by viruses, bacteria, allergens, or irritants1 4. Viral conjunctivitis is the most frequent and highly contagious type, often resolving without specific treatment7 . Bacterial conjunctivitis may require antibiotics to shorten illness and prevent spread17 . Allergic conjunctivitis is not contagious and is managed by avoiding allergens and using antihistamines11 . Good hygiene is essential to prevent transmission, especially in children and newborns9 . While complications are rare, severe or persistent cases need medical attention to protect vision6 14.
