Bacterial Conjunctivitis

Bacterial conjunctivitis, commonly known as pink eye, is a highly contagious infection that causes inflammation of the eye's outer membrane, leading to redness, discharge, and discomfort.

Overview

Bacterial conjunctivitis is one of the most common eye infections, affecting millions of people worldwide each year. This condition occurs when bacteria infect the conjunctiva, the thin, transparent membrane that lines the inner surface of the eyelid and covers the white part of the eye. The infection causes inflammation, leading to the characteristic pink or red appearance that gives the condition its common name, "pink eye."

This highly contagious condition can affect one or both eyes and spreads easily through direct contact with infected eye secretions or contaminated objects. While bacterial conjunctivitis can occur at any age, it's particularly common in children due to their close contact with others in schools and daycare settings, as well as their tendency to touch their eyes frequently. The condition is also more prevalent during certain seasons, particularly in warmer months when bacteria thrive.

Although bacterial conjunctivitis can be uncomfortable and concerning, it's generally not a serious condition and rarely causes long-term vision problems when properly treated. With appropriate antibiotic treatment, most cases resolve within a week to ten days. However, prompt diagnosis and treatment are important to prevent spread to others and to ensure rapid recovery. Understanding the symptoms, causes, and proper management of bacterial conjunctivitis is essential for maintaining good eye health and preventing transmission.

Symptoms

Bacterial conjunctivitis presents with distinctive symptoms that typically develop rapidly and can affect one or both eyes. The symptoms often start in one eye and spread to the other within a few days.

Primary Eye Symptoms

  • Eye redness: The white part of the eye becomes pink or red due to inflammation of blood vessels in the conjunctiva. This is often the most noticeable symptom.
  • Eye discharge: Thick, yellow, white, or green discharge that may cause the eyelids to stick together, especially after sleep. This discharge is typically more pronounced than in viral conjunctivitis.
  • Crusting of eyelids: Dried discharge forms crusts on the eyelashes and eyelid margins, particularly noticeable upon waking.
  • Gritty sensation: Feeling like sand or grit is in the eye, causing discomfort and the urge to rub the eyes.
  • Tearing: Excessive tear production as the eye attempts to flush out irritants.
  • Mild eye pain: Generally less severe than with other eye conditions, but can cause discomfort.
  • Light sensitivity: Mild photophobia or discomfort in bright light.

Associated Symptoms

  • Sore throat: May occur when the infection is part of a broader upper respiratory infection or when bacteria spread from the eyes to the throat.
  • Nasal congestion: Common when conjunctivitis occurs alongside upper respiratory infections.
  • Cough: May be present if the bacterial infection affects other parts of the respiratory system.
  • Fever: Low-grade fever may occur, especially in children or when the infection is more severe.
  • Abnormal appearing skin: Redness or irritation around the eyes from rubbing or from the infection spreading to nearby skin.
  • Swollen eyelids: The eyelids may appear puffy or swollen due to inflammation.
  • Enlarged lymph nodes: Preauricular lymph nodes (in front of the ears) may be swollen and tender.

Symptoms Requiring Immediate Medical Attention

  • Severe eye pain
  • Significant vision changes or blurred vision that doesn't clear with blinking
  • Intense light sensitivity
  • Signs of corneal involvement (white spot on the cornea)
  • Symptoms not improving after 24 hours of antibiotic treatment
  • High fever or signs of systemic illness

Causes

Bacterial conjunctivitis is caused by various types of bacteria that infect the conjunctiva. Understanding these causative agents and how they spread is crucial for prevention and treatment.

Common Bacterial Causes

  • Staphylococcus aureus: The most common cause in adults, responsible for approximately 40-50% of bacterial conjunctivitis cases. This includes methicillin-resistant S. aureus (MRSA).
  • Streptococcus pneumoniae: Common in children and adults, often associated with more severe symptoms and concurrent respiratory infections.
  • Haemophilus influenzae: Particularly common in children, often causing conjunctivitis-otitis syndrome (concurrent ear and eye infection).
  • Moraxella catarrhalis: More common in children and often associated with upper respiratory infections.
  • Pseudomonas aeruginosa: Associated with contact lens use and can cause severe keratitis if not treated promptly.

Less Common Bacterial Causes

  • Neisseria gonorrhoeae: Causes hyperacute conjunctivitis with copious purulent discharge, requires urgent treatment.
  • Chlamydia trachomatis: Causes inclusion conjunctivitis in newborns and adults, often sexually transmitted.
  • Corynebacterium diphtheriae: Rare but serious cause, associated with membrane formation.

Modes of Transmission

  • Direct contact: Touching infected eye secretions and then touching one's own eyes.
  • Contaminated objects: Sharing towels, pillowcases, cosmetics, or eye drops with infected individuals.
  • Respiratory droplets: Coughing or sneezing can spread bacteria, especially when conjunctivitis occurs with respiratory infections.
  • Poor hygiene: Not washing hands properly after touching the face or eyes.
  • Contaminated water: Swimming pools or hot tubs with inadequate chlorination.
  • Birth canal transmission: Newborns can acquire infection during vaginal delivery from infected mothers.

Risk Factors

Several factors increase the likelihood of developing bacterial conjunctivitis. Understanding these risk factors can help in prevention and early intervention.

Environmental and Social Factors

  • Crowded living conditions: Schools, daycare centers, dormitories, and nursing homes facilitate rapid spread.
  • Poor hygiene practices: Inadequate handwashing and frequent eye touching.
  • Seasonal factors: Higher incidence during warmer months when bacteria proliferate more readily.
  • Close contact with infected individuals: Family members or classmates with active infection.

Personal Health Factors

  • Contact lens use: Especially with poor lens hygiene, extended wear, or sleeping in lenses.
  • Compromised immune system: HIV/AIDS, diabetes, cancer treatment, or immunosuppressive medications.
  • Chronic eye conditions: Dry eye syndrome, blepharitis, or previous eye surgery.
  • Upper respiratory infections: Concurrent sinus or ear infections increase risk.
  • Skin conditions: Atopic dermatitis or seborrheic dermatitis around the eyes.

Age-Related Factors

  • Young children: Higher risk due to developing immune systems and poor hygiene habits.
  • Elderly individuals: Weakened immune systems and higher prevalence of chronic conditions.
  • Newborns: Risk of neonatal conjunctivitis from birth canal transmission.

Occupational and Lifestyle Factors

  • Healthcare workers: Increased exposure to infected patients.
  • Childcare providers and teachers: Frequent contact with children who have higher infection rates.
  • Shared cosmetics: Using contaminated eye makeup or sharing with others.
  • Swimming: In poorly maintained pools or natural water bodies.

Diagnosis

Diagnosing bacterial conjunctivitis typically involves a clinical examination, though laboratory testing may be necessary in certain cases to confirm the diagnosis and guide treatment.

Clinical Examination

The diagnosis is often made based on clinical presentation:

  • Visual inspection: Examining the eye for characteristic redness, discharge, and swelling.
  • Patient history: Questions about symptom onset, discharge characteristics, recent exposures, and associated symptoms.
  • Slit lamp examination: Detailed examination of eye structures to rule out corneal involvement or other complications.
  • Visual acuity testing: To ensure vision is not significantly affected.

Distinguishing Features

Key features that suggest bacterial rather than viral conjunctivitis:

  • Purulent (thick, colored) discharge rather than watery discharge
  • Eyelids stuck together upon waking
  • Absence of preauricular lymphadenopathy (more common in viral)
  • Usually affects one eye initially (viral often affects both simultaneously)
  • Concurrent ear infection (especially in children)

Laboratory Testing

Culture and sensitivity testing may be indicated in certain situations:

  • Severe or hyperacute conjunctivitis: Copious purulent discharge suggesting gonococcal infection.
  • Neonatal conjunctivitis: All cases in newborns require culture.
  • Treatment failure: Symptoms not improving after 48-72 hours of antibiotic therapy.
  • Recurrent infections: Multiple episodes suggesting resistant organisms.
  • Contact lens wearers: Higher risk of Pseudomonas and other serious pathogens.
  • Immunocompromised patients: Higher risk of unusual pathogens.

Additional Tests

  • Gram stain: Rapid identification of bacterial type to guide initial treatment.
  • PCR testing: For specific pathogens like Chlamydia in suspected cases.
  • Corneal staining: Fluorescein dye to rule out corneal abrasions or ulcers.

Treatment Options

Treatment of bacterial conjunctivitis aims to eliminate the infection, reduce symptoms, prevent spread, and avoid complications. The approach varies based on severity and patient factors.

Antibiotic Therapy

Topical antibiotics are the mainstay of treatment:

  • Broad-spectrum antibiotic drops:
    • Polymyxin B/trimethoprim: 1 drop 4 times daily for 7-10 days
    • Fluoroquinolones (moxifloxacin, ciprofloxacin): 1-2 drops 4 times daily
    • Azithromycin: 1 drop twice daily for 2 days, then once daily for 5 days
  • Antibiotic ointments:
    • Erythromycin: Applied 2-4 times daily, preferred in children
    • Bacitracin/polymyxin B: Applied 3-4 times daily
    • Tobramycin: For more resistant cases

Supportive Care

  • Warm compresses: Apply for 5-10 minutes, 3-4 times daily to remove crusts and provide comfort.
  • Artificial tears: Preservative-free lubricating drops to flush discharge and soothe irritation.
  • Eyelid hygiene: Gentle cleaning with warm water or saline to remove discharge.
  • Cold compresses: May help reduce swelling and discomfort.

Special Considerations

  • Contact lens wearers: Discontinue lens use until infection clears; discard current lenses and cases.
  • Severe infections: May require systemic antibiotics, especially for gonococcal or chlamydial conjunctivitis.
  • Children: Ointments often preferred due to easier application and longer contact time.
  • Pregnancy: Erythromycin and polymyxin B are generally considered safe.

What to Avoid

  • Steroid eye drops without medical supervision (can worsen certain infections)
  • Sharing eye drops or ointments
  • Wearing eye makeup until infection clears
  • Rubbing or touching the eyes
  • Using over-the-counter "red eye" drops (may mask symptoms)

Treatment Duration and Follow-up

  • Continue antibiotics for the full prescribed course, even if symptoms improve
  • Most cases resolve within 7-10 days with treatment
  • Follow-up if symptoms worsen or don't improve within 48-72 hours
  • Return to school/work typically allowed 24 hours after starting antibiotics

Prevention

Preventing bacterial conjunctivitis focuses on good hygiene practices and avoiding transmission from infected individuals.

Personal Hygiene

  • Hand washing: Wash hands frequently with soap and water for at least 20 seconds, especially after touching the face or eyes.
  • Avoid eye touching: Minimize touching or rubbing eyes with unwashed hands.
  • Personal items: Don't share towels, washcloths, pillowcases, or cosmetics.
  • Proper tissue use: Use tissues to wipe eyes and dispose immediately; wash hands afterward.

Contact Lens Care

  • Follow proper lens hygiene and replacement schedules
  • Never sleep in contact lenses unless specifically designed for extended wear
  • Replace lens cases every 3 months
  • Use only recommended cleaning solutions
  • Never use tap water or saliva on lenses

Environmental Measures

  • Disinfection: Clean frequently touched surfaces with appropriate disinfectants.
  • Separate linens: Use separate towels and washcloths for infected family members.
  • Laundry: Wash contaminated items in hot water with detergent.
  • Swimming precautions: Avoid swimming pools during active infection; wear goggles when swimming.

In Schools and Daycare

  • Teach children proper handwashing techniques
  • Discourage sharing of personal items
  • Clean toys and surfaces regularly
  • Exclude infected children until 24 hours after starting treatment
  • Notify parents of outbreaks for early detection

When to See a Doctor

While many cases of bacterial conjunctivitis are mild, certain situations require prompt medical evaluation to prevent complications and ensure appropriate treatment.

Seek Immediate Medical Care If:

  • Severe eye pain or significant vision changes
  • Copious, thick purulent discharge (possible gonococcal infection)
  • Light sensitivity with eye pain (possible corneal involvement)
  • White spot on the cornea
  • Symptoms in a newborn or infant under 1 month
  • High fever with eye symptoms
  • Recent eye surgery or injury

Schedule an Appointment If:

  • Eye redness with discharge lasting more than 1-2 days
  • Symptoms not improving after 24-48 hours of over-the-counter treatment
  • Recurrent episodes of conjunctivitis
  • Contact lens wearer with red eye
  • Concurrent ear infection or sore throat
  • Known exposure to someone with bacterial conjunctivitis
  • Immunocompromised status

Follow-up Care

Return to your healthcare provider if:

  • Symptoms worsen despite treatment
  • New symptoms develop (vision changes, severe pain)
  • No improvement after 3 days of antibiotic treatment
  • Side effects from medications
  • Questions about returning to work or school

Related Conditions

Frequently Asked Questions

How long is bacterial conjunctivitis contagious?

Bacterial conjunctivitis is contagious as long as there is discharge from the eye. With antibiotic treatment, it typically becomes non-contagious 24 hours after starting medication. Without treatment, it can remain contagious for up to 2 weeks.

Can bacterial conjunctivitis go away without antibiotics?

Mild cases may resolve on their own within 7-14 days. However, antibiotic treatment speeds recovery, reduces contagiousness, and prevents complications. It's best to see a healthcare provider for proper diagnosis and treatment.

Can I wear contact lenses with bacterial conjunctivitis?

No, you should stop wearing contact lenses immediately if you develop conjunctivitis. Discard your current lenses and case, and don't resume wearing contacts until your eye doctor confirms the infection has cleared completely.

Is pink eye always bacterial?

No, pink eye (conjunctivitis) can be caused by bacteria, viruses, allergens, or irritants. Bacterial conjunctivitis typically has thicker, colored discharge, while viral conjunctivitis usually has watery discharge. Proper diagnosis is important for appropriate treatment.

Can bacterial conjunctivitis affect vision permanently?

Most cases of bacterial conjunctivitis don't cause permanent vision problems when properly treated. However, severe infections, especially those involving the cornea or caused by aggressive bacteria like gonorrhea, can lead to vision complications if not treated promptly.

References

  1. American Academy of Ophthalmology. (2023). Conjunctivitis Preferred Practice Pattern. AAO.
  2. Centers for Disease Control and Prevention. (2023). Conjunctivitis (Pink Eye). CDC.
  3. Azari, A. A., & Barney, N. P. (2023). Conjunctivitis: A systematic review of diagnosis and treatment. JAMA, 310(16), 1721-1729.
  4. Sheikh, A., & Hurwitz, B. (2023). Antibiotics versus placebo for acute bacterial conjunctivitis. Cochrane Database of Systematic Reviews.
  5. Jefferis, J., Perera, R., Everitt, H., et al. (2023). Acute infective conjunctivitis in primary care: who needs antibiotics? British Journal of General Practice.