Conjunctivitis: Symptoms, Causes & Treatment Guide

What Is Conjunctivitis?

Conjunctivitis is inflammation of the conjunctiva, the clear membrane that covers the white part of the eye and lines the inner eyelids. This condition causes the small blood vessels in the conjunctiva to become inflamed and more visible, giving the eye a pink or red appearance—hence the common name "pink eye."

The conjunctiva plays an essential protective role for your eyes. It produces mucus and tears that help lubricate the eye surface, and it contains immune cells that help defend against infections. When the conjunctiva becomes inflamed, whether due to infection, allergies, or irritants, it triggers a cascade of symptoms that can range from mild discomfort to significant impairment of daily activities.

Conjunctivitis is remarkably common, affecting millions of people worldwide each year. It accounts for a significant portion of eye-related visits to healthcare providers and is one of the leading causes of school absences in children. While the condition is usually not serious and resolves without complications, understanding its various forms and proper management can help minimize discomfort and prevent spread to others.

The inflammation can affect one or both eyes. Often, when caused by infection, it starts in one eye and spreads to the other within a day or two through contact with contaminated hands or shared items. The course of the disease varies depending on the underlying cause, with viral cases typically lasting longer than bacterial infections.

Types of Conjunctivitis

Understanding the different types of conjunctivitis is crucial for appropriate treatment. Each type has distinct characteristics, causes, and management approaches:

• Viral Conjunctivitis: The most common form, caused by viruses (often the same ones that cause colds). Produces watery discharge and typically resolves in 7-14 days without treatment.
• Bacterial Conjunctivitis: Caused by bacteria, produces thick yellow-green discharge that may cause eyelids to stick together. Usually responds to antibiotic drops.
• Allergic Conjunctivitis: Triggered by allergens like pollen, dust mites, or pet dander. Causes intense itching and affects both eyes simultaneously. Not contagious.
• Chemical/Irritant Conjunctivitis: Results from exposure to irritating substances like chlorine, smoke, or foreign bodies. Treatment focuses on removing the irritant.

What Are the Symptoms of Conjunctivitis?

The hallmark symptoms of conjunctivitis include eye redness, discharge (watery or thick), itching, a gritty or sandy sensation, tearing, and crusting of the eyelids—especially upon waking. The specific combination and severity of symptoms often help distinguish between viral, bacterial, and allergic causes.

Symptoms of conjunctivitis can develop rapidly, often within hours of exposure to an infectious agent or allergen. The presentation varies depending on the underlying cause, but several symptoms are common across all types of conjunctivitis. Recognizing these symptoms early allows for prompt treatment and measures to prevent spreading the infection to others.

The redness characteristic of conjunctivitis results from dilation of the small blood vessels in the conjunctiva. This is the body's inflammatory response to infection or irritation. While redness is universal to all forms of conjunctivitis, the pattern and intensity can provide clues about the cause.

Discharge is another key symptom that varies significantly between types. The nature of the discharge—whether clear and watery, mucoid, or thick and purulent—helps healthcare providers determine whether antibiotics are needed and guides treatment decisions.

Symptoms of Viral Conjunctivitis

Viral conjunctivitis, the most common form, typically presents with distinctive features that help differentiate it from other types. Understanding these symptoms helps patients know what to expect during the course of the illness and when home care is sufficient.

• Watery, clear discharge from the eye
• Redness that may be more pronounced in one eye initially
• Burning or gritty sensation
• Light sensitivity (photophobia)
• Often accompanies cold symptoms (runny nose, sore throat)
• Swollen lymph nodes in front of the ear (preauricular adenopathy)
• Symptoms typically start in one eye and spread to the other

Viral conjunctivitis is highly contagious and spreads easily through direct contact with infected secretions. The contagious period typically lasts 10-14 days from symptom onset. Adenoviruses are the most common causative agents, accounting for 65-90% of viral conjunctivitis cases.

Symptoms of Bacterial Conjunctivitis

Bacterial conjunctivitis produces more dramatic symptoms related to the body's response to bacterial infection. The most distinguishing feature is the type of discharge produced, which reflects the immune system's active fight against the bacteria.

• Thick, yellow-green or gray discharge
• Eyelids stuck together upon waking ("matted eyes")
• Swelling of the eyelids
• Redness usually affects both eyes
• Moderate to severe discomfort
• Foreign body sensation
• No associated cold symptoms typically

Common bacteria responsible for this type include Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenzae. Bacterial conjunctivitis is particularly common in children and often occurs in outbreaks in daycare settings and schools. Without treatment, bacterial conjunctivitis usually resolves within 7-10 days, but antibiotic treatment can shorten the duration and reduce the risk of complications.

Symptoms of Allergic Conjunctivitis

Allergic conjunctivitis presents with a distinctive symptom profile that reflects the allergic nature of the condition. The most prominent feature is itching, which is typically more intense than in infectious forms of conjunctivitis.

• Intense itching—often the predominant symptom
• Both eyes affected simultaneously and equally
• Clear, watery discharge
• Puffy, swollen eyelids
• Associated nasal symptoms (sneezing, congestion)
• Seasonal pattern if caused by pollen
• History of other allergic conditions (eczema, asthma)

What Causes Conjunctivitis?

Conjunctivitis is caused by viral infections (most commonly adenovirus), bacterial infections (Staphylococcus, Streptococcus), allergens (pollen, dust mites, pet dander), or irritants (smoke, chlorine, foreign bodies). The cause determines whether the condition is contagious and what treatment is needed.

Understanding the causes of conjunctivitis is essential for proper treatment and prevention. The conjunctiva, despite its protective role, is constantly exposed to the external environment and therefore vulnerable to various infectious agents, allergens, and irritants. The body's response to these exposures results in the inflammation we recognize as conjunctivitis.

Infectious conjunctivitis—whether viral or bacterial—spreads through direct or indirect contact with infected secretions. This can occur through touching the eye with contaminated hands, sharing personal items like towels or makeup, or exposure to respiratory droplets from an infected person. Understanding these transmission routes is key to preventing the spread of infection.

Non-infectious causes include allergic reactions and exposure to irritants. These forms of conjunctivitis are not contagious but can be equally troublesome and may require different management approaches. Allergic conjunctivitis, in particular, can significantly impact quality of life during allergy seasons.

Viral Causes

Viruses are the most common cause of infectious conjunctivitis, responsible for up to 80% of acute cases. Several virus families can cause eye infections, each with somewhat different clinical presentations and courses.

• Adenovirus: The most common cause (65-90% of viral cases), often associated with upper respiratory infections and can cause epidemic outbreaks
• Herpes simplex virus: Can cause more severe disease with potential corneal involvement; requires specific antiviral treatment
• Varicella-zoster virus: May cause conjunctivitis as part of shingles affecting the face; requires urgent treatment
• Enterovirus: Can cause acute hemorrhagic conjunctivitis, particularly in tropical regions

Bacterial Causes

Bacterial conjunctivitis is less common than viral but is more amenable to specific treatment with antibiotics. Several bacterial species commonly cause eye infections, and the specific organism may vary by age group and geographic region.

• Staphylococcus aureus: Most common cause in adults; often associated with blepharitis
• Streptococcus pneumoniae: Common in children; may cause more severe inflammation
• Haemophilus influenzae: Particularly common in children; may cause outbreak in daycare settings
• Moraxella species: Can cause chronic conjunctivitis; associated with poor hygiene
• Chlamydia trachomatis: Causes inclusion conjunctivitis in adults and neonatal conjunctivitis; requires systemic treatment
• Neisseria gonorrhoeae: Rare but severe; causes hyperacute bacterial conjunctivitis requiring urgent treatment

Allergic and Irritant Causes

Non-infectious conjunctivitis results from the eye's reaction to various environmental factors. These causes are important to identify as they require different management approaches than infectious conjunctivitis.

• Seasonal allergens: Tree pollen (spring), grass pollen (summer), ragweed (fall)
• Perennial allergens: Dust mites, pet dander, mold spores
• Chemical irritants: Chlorine in swimming pools, smoke, air pollution
• Contact lens solutions: Preservatives in lens care products can cause sensitivity reactions
• Cosmetics: Eye makeup, facial cleansers, lotions near the eyes
• Foreign bodies: Dust, sand, or other particles in the eye

When Should You See a Doctor for Conjunctivitis?

Seek medical care if you experience severe eye pain, vision changes, sensitivity to light, thick green/yellow discharge that persists, symptoms that don't improve within 5 days, or if a newborn develops eye symptoms. Immediate emergency care is needed for sudden vision loss or severe eye injury.

While most cases of conjunctivitis resolve on their own or with simple home care, certain situations require professional medical evaluation. Recognizing these warning signs ensures that potentially serious conditions are identified and treated promptly, preventing complications that could affect vision.

The decision to seek care depends on symptom severity, duration, and the presence of concerning features. Most viral conjunctivitis will resolve within two weeks without specific treatment, and bacterial conjunctivitis often improves even without antibiotics. However, some cases warrant medical attention to rule out more serious conditions or to provide appropriate treatment.

It's particularly important to seek care if you have underlying conditions that affect the immune system or if you wear contact lenses, as these factors increase the risk of complications from eye infections.

Warning Signs Requiring Medical Evaluation

Several symptoms suggest that conjunctivitis may be more serious than a simple viral or bacterial infection, or that an alternative diagnosis should be considered.

• Symptoms persisting beyond 5-7 days without improvement
• Increasing pain or redness despite home treatment
• Significant light sensitivity (photophobia)
• Blurred vision that doesn't clear with blinking
• Copious thick discharge despite regular cleaning
• Swelling extending beyond the eyelid
• Symptoms affecting only one eye with severe redness
• History of recent herpes outbreak

Special Considerations

Certain groups should have a lower threshold for seeking medical care due to increased risk of complications or the potential for more serious underlying conditions.

How Can You Treat Conjunctivitis at Home?

Home treatment for conjunctivitis includes cleaning eyes gently with lukewarm water, applying warm compresses to loosen crusted discharge, using artificial tears for comfort, avoiding contact lenses, and practicing strict hand hygiene. These measures help relieve symptoms and prevent spreading infection.

Many cases of conjunctivitis, particularly viral infections, resolve without specific medical treatment. Home care focuses on relieving symptoms, preventing the spread of infection, and supporting the body's natural healing process. Understanding proper techniques for eye hygiene is essential for effective home management.

The most important aspect of home care is keeping the eyes clean. Discharge that accumulates can be uncomfortable and may provide a medium for bacterial growth. Regular cleaning helps maintain comfort and may speed recovery. Additionally, proper hygiene prevents spreading the infection to others or to your other eye if only one is affected.

Artificial tears can provide significant relief by lubricating the eye surface, diluting inflammatory mediators, and washing away debris and discharge. They are safe to use frequently throughout the day and do not interfere with the healing process or any prescribed treatments.

Step-by-Step Eye Cleaning

Proper eye cleaning technique is crucial for effective home management of conjunctivitis. Follow these steps to clean your eyes safely and effectively:

1. Wash your hands thoroughly with soap and water for at least 20 seconds before touching your face or eyes
2. Prepare clean materials: Use a fresh cotton ball, gauze pad, or clean tissue moistened with lukewarm (not hot) water
3. Clean from outer to inner corner: Gently wipe from the outer corner of the eye toward the nose, using a single stroke
4. Use fresh material for each wipe: Discard the cotton ball or tissue after one use and use a new one for subsequent wipes
5. For stuck eyelids: Hold a warm, moist compress against the closed eye for 1-2 minutes to loosen crusted discharge before wiping
6. Clean both eyes separately: If both eyes are affected, use separate materials for each eye to avoid cross-contamination
7. Wash hands again after cleaning to prevent spreading infection

Additional Home Care Measures

• Warm compresses: Apply a clean, warm washcloth to closed eyes for 5-10 minutes several times daily to soothe discomfort
• Cool compresses: For allergic conjunctivitis, cool compresses may provide more relief than warm ones
• Artificial tears: Use preservative-free artificial tears 4-6 times daily or as needed for comfort
• Avoid contact lenses: Stop wearing contact lenses until symptoms completely resolve; discard current disposable lenses
• Remove eye makeup: Avoid eye makeup during infection; discard any products used before or during the infection
• Protect from light: Wear sunglasses if you have light sensitivity

How Can You Prevent Spreading Conjunctivitis?

Prevent conjunctivitis spread by washing hands frequently, avoiding touching your eyes, not sharing personal items like towels and makeup, changing pillowcases daily, and keeping children with heavy discharge home from school or daycare until symptoms improve.

Prevention is crucial for controlling the spread of infectious conjunctivitis, which is highly contagious. Simple hygiene measures can significantly reduce transmission to family members, classmates, and colleagues. The virus or bacteria can survive on surfaces for hours to days, making environmental hygiene as important as personal hygiene.

The infectious period for conjunctivitis typically lasts as long as discharge is present. For viral conjunctivitis, this can be 10-14 days or even longer. Bacterial conjunctivitis becomes much less contagious after 24-48 hours of antibiotic treatment. Understanding these timelines helps in making decisions about work, school, and social activities.

In healthcare settings, schools, and workplaces, proper infection control measures can prevent outbreaks that affect many people. Educating family members and caregivers about prevention is especially important when children are affected, as they may be less capable of maintaining hygiene measures independently.

Hand Hygiene Best Practices

Hand washing is the single most effective measure for preventing the spread of conjunctivitis. Proper technique ensures that infectious agents are removed effectively.

• Wash hands for at least 20 seconds with soap and water
• Use hand sanitizer with at least 60% alcohol when soap is unavailable
• Wash hands before and after touching the face or eyes
• Wash hands after applying eye drops or cleaning the eyes
• Teach children proper hand washing technique
• Keep hand sanitizer readily accessible throughout the day

Environmental and Personal Hygiene

• Personal items: Do not share towels, washcloths, pillowcases, or eye cosmetics
• Bedding: Change pillowcases daily during active infection; wash bedding in hot water
• Surfaces: Clean frequently touched surfaces with disinfectant
• Eye makeup: Discard any eye makeup used during infection; do not share makeup with others
• Contact lenses: Discard disposable lenses worn during infection; disinfect lens cases thoroughly
• Swimming: Avoid swimming pools until infection clears to prevent spreading and irritation

School and Daycare Guidelines

Children with conjunctivitis often face decisions about attending school or daycare. Guidelines help balance the need to prevent spread with practical considerations for families.

• Heavy discharge: Children with significant discharge should stay home as they are most contagious and need frequent eye cleaning
• With antibiotic treatment: Children can typically return after 24-48 hours of antibiotic treatment for bacterial conjunctivitis
• Mild symptoms: Children with minimal symptoms and good hygiene habits may be able to attend if they can avoid touching their eyes
• Allergic conjunctivitis: Not contagious—children can attend school but may need medication for comfort

How Is Conjunctivitis Treated?

Treatment depends on the type of conjunctivitis. Viral conjunctivitis usually resolves without medication in 7-14 days. Bacterial conjunctivitis requires antibiotic eye drops or ointment. Allergic conjunctivitis responds to antihistamine drops, cool compresses, and avoiding triggers. All types benefit from supportive care with artificial tears.

The approach to treating conjunctivitis depends critically on identifying the underlying cause. While symptoms may appear similar, viral, bacterial, and allergic conjunctivitis require different management strategies. Accurate diagnosis by a healthcare provider ensures that appropriate treatment is provided and unnecessary antibiotics are avoided when they won't be helpful.

For viral conjunctivitis, the mainstay of treatment is supportive care. Since antibiotics do not work against viruses, treatment focuses on relieving symptoms while the body's immune system clears the infection naturally. This typically takes 7-14 days, though some viral infections can persist for several weeks.

Bacterial conjunctivitis benefits from antibiotic treatment, which can shorten the duration of symptoms, reduce the contagious period, and decrease the risk of complications. However, even bacterial conjunctivitis often resolves spontaneously within 7-10 days, so healthcare providers may sometimes recommend a "watch and wait" approach for mild cases.

Treatment for Viral Conjunctivitis

Since there is no specific antiviral treatment for most viral conjunctivitis, management focuses on symptom relief and preventing complications.

• Artificial tears: Use preservative-free drops 4-6 times daily to relieve dryness and discomfort
• Cool compresses: Apply to closed eyes for 10-15 minutes several times daily
• Avoid contact lenses: Do not wear lenses until all symptoms have resolved
• Limit screen time: Reduce eye strain during recovery
• Antiviral medications: Only prescribed for specific viral causes like herpes simplex virus

Treatment for Bacterial Conjunctivitis

Antibiotic eye drops or ointments are effective for bacterial conjunctivitis and are typically prescribed when bacterial infection is confirmed or strongly suspected.

• Antibiotic eye drops: Common options include fluoroquinolones, aminoglycosides, or polymyxin B combinations
• Antibiotic ointment: May be preferred for children as they remain in the eye longer
• Duration: Typically 5-7 days; complete the full course even if symptoms improve
• Application: Follow healthcare provider instructions carefully for proper administration
• Improvement timeline: Symptoms usually improve within 2-3 days of starting treatment

Treatment for Allergic Conjunctivitis

Managing allergic conjunctivitis involves both treating acute symptoms and preventing recurrences by minimizing exposure to triggers.

• Antihistamine eye drops: Provide rapid relief from itching; some are available over-the-counter
• Mast cell stabilizers: Help prevent allergic reactions; most effective when used regularly during allergy season
• Combination drops: Contain both antihistamines and mast cell stabilizers for comprehensive relief
• Cool compresses: Particularly soothing for allergic symptoms
• Oral antihistamines: May help if nasal and eye symptoms occur together
• Allergen avoidance: Keep windows closed during high pollen days, use air purifiers, wash bedding frequently

What Are the Possible Complications?

Most conjunctivitis cases resolve without complications. Rare complications include corneal involvement (keratitis) that can affect vision, chronic conjunctivitis, and in newborns, potentially serious systemic infections. Prompt treatment and recognizing warning signs minimize complication risks.

While conjunctivitis is usually a self-limited condition with an excellent prognosis, complications can occasionally occur. Understanding potential complications helps patients recognize when to seek additional medical attention and reassures them that serious outcomes are uncommon with proper care.

The most concerning potential complication is spread of infection to the cornea (keratitis), which can cause scarring and permanent vision impairment if not treated promptly. This is more common with certain organisms, particularly herpes viruses and some bacteria, and is more likely in people who wear contact lenses or have compromised immune systems.

For most people, conjunctivitis resolves completely without any lasting effects. The discomfort and inconvenience, while troublesome, are temporary, and the eyes return to normal function once the inflammation subsides.

Potential Complications

• Keratitis: Spread of infection to the cornea, causing pain, light sensitivity, and potentially vision changes
• Chronic conjunctivitis: Persistent inflammation requiring ongoing treatment
• Scarring: Rare, but can occur with severe bacterial infections
• Neonatal complications: Infections in newborns can spread to other organs if not treated promptly
• Post-viral syndrome: Prolonged mild symptoms after acute viral conjunctivitis resolves