Overview
Acute Conjunctivitis
1. Clinical Overview
Summary
Conjunctivitis is inflammation of the conjunctiva - the most common eye condition. Most is viral (self-limited, supportive care). Bacterial requires topical antibiotics. Gonococcal is an emergency (can perforate cornea). Key ED task: distinguish from keratitis, iritis, glaucoma.
Key Facts
- Cause: Viral (50-70%), bacterial (10-30%), allergic (15-25%)
- Viral: Watery discharge, preauricular nodes, self-limited
- Bacterial: Purulent discharge, treat with topical antibiotics
- Emergency: Gonococcal (hyperacute purulent) → systemic antibiotics
2. Epidemiology
Overview
Conjunctivitis is inflammation of the conjunctiva, the transparent membrane covering the sclera and lining the eyelids. It is one of the most common eye conditions. Most cases are viral and self-limited. The key ED task is distinguishing benign conjunctivitis from serious conditions (keratitis, iritis, glaucoma) and identifying hyperacute gonococcal conjunctivitis, which is an emergency.
Classification
By Etiology:
| Type | Features |
|---|---|
| Viral | Most common; watery discharge, URI association |
| Bacterial | Purulent discharge; may be mild or hyperacute |
| Allergic | Itching, bilateral, seasonal |
| Chemical/Irritant | Exposure history |
| Chlamydial | Chronic, follicular; STI |
Epidemiology
- Very common: 6 million cases/year in US
- Viral most common: 50-70%
- Bacterial: 10-30%
- Allergic: 15-25%
Etiology
Viral:
| Virus | Notes |
|---|---|
| Adenovirus | Most common; highly contagious |
| Herpes simplex | Consider if recurrent, dendritic lesions |
| Enterovirus | Epidemic hemorrhagic conjunctivitis |
Bacterial:
| Organism | Notes |
|---|---|
| Staphylococcus aureus | Common |
| Streptococcus pneumoniae | Common |
| Haemophilus influenzae | More common in children |
| Moraxella | |
| Neisseria gonorrhoeae | Hyperacute, purulent, can perforate cornea |
| Chlamydia trachomatis | Chronic, STI |
| Pseudomonas | Contact lens wearers |
3. Pathophysiology
Mechanism
- Pathogen or allergen contact: Conjunctival surface
- Inflammatory response: Vasodilation → Red eye
- Mucus/pus production: Discharge
- Chemosis: Conjunctival edema
Transmission
- Direct contact (hands, fomites)
- Respiratory droplets (viral)
- Sexual transmission (GC, chlamydia)
- Highly contagious (viral): 10-14 days
4. Clinical Presentation
Symptoms
| Symptom | Description |
|---|---|
| Red eye | Conjunctival injection |
| Discharge | Watery (viral), purulent (bacterial), stringy (allergic) |
| Itching | Prominent in allergic |
| Tearing | Common |
| Gritty sensation | Foreign body feeling |
| Eyelid crusting | Especially in morning |
| Photophobia | Mild or absent (if present, consider keratitis) |
History
Key Questions:
Physical Examination
Eye Exam:
| Finding | Significance |
|---|---|
| Conjunctival injection | Diffuse (conjunctivitis) vs ciliary flush (iritis) |
| Discharge | Characterize (watery, mucopurulent, purulent) |
| Chemosis | Conjunctival edema |
| Papillae | Bacterial or allergic |
| Follicles | Viral or chlamydial |
| Preauricular lymphadenopathy | Viral |
| Cornea clear | If hazy, consider keratitis |
| Pupil round and reactive | Fixed/dilated = Glaucoma |
Visual Acuity:
Onset and duration
Common presentation.
Unilateral or bilateral
Common presentation.
Type of discharge (watery, purulent)
Common presentation.
Itching (allergic)
Common presentation.
Contact lens use
Common presentation.
Recent URI or sick contacts
Common presentation.
Sexual history (STI risk)
Common presentation.
Vision changes (red flag)
Common presentation.
Photophobia (red flag)
Common presentation.
5. Clinical Examination
(Integrated into Clinical Presentation above)
Red Flags
Serious Conditions to Exclude
| Finding | Concern | Action |
|---|---|---|
| Decreased visual acuity | Keratitis, iritis, glaucoma | Slit lamp, ophthalmology |
| Severe photophobia | Keratitis, iritis | Slit lamp, ophthalmology |
| Ciliary flush (perilimbal injection) | Iritis | Ophthalmology |
| Fixed mid-dilated pupil | Angle-closure glaucoma | Emergent ophthalmology |
| Corneal opacity/ulcer | Keratitis | Ophthalmology |
| Hyperacute onset, copious purulent discharge | Gonococcal | Urgent treatment |
| Contact lens + red eye | Pseudomonas keratitis risk | Remove lens, fluoroquinolone |
| Neonate with conjunctivitis | Ophthalmia neonatorum | Urgent, treat for GC/chlamydia |
6. Investigations
Differential Diagnosis
| Diagnosis | Key Features |
|---|---|
| Iritis/Uveitis | Photophobia, ciliary flush, cells/flare |
| Keratitis | Photophobia, corneal opacity, decreased VA |
| Angle-closure glaucoma | Severe pain, halos, fixed dilated pupil |
| Corneal abrasion | Foreign body sensation, fluorescein uptake |
| Subconjunctival hemorrhage | Localized red, no discharge |
| Episcleritis/Scleritis | Sectoral or diffuse injection, scleritis is painful |
| Foreign body | History, visible on exam |
Diagnostic Approach
Clinical Diagnosis
- Conjunctivitis is a clinical diagnosis
- Based on history and exam
When to Do Further Testing
| Indication | Test |
|---|---|
| Hyperacute purulent | Conjunctival swab for GC/Chlamydia (Gram stain, culture, NAAT) |
| Neonatal conjunctivitis | GC/Chlamydia testing |
| Contact lens wearer with keratitis | Corneal culture |
| Chronic or recurrent | Chlamydia testing |
Slit Lamp Exam
- For all patients with decreased VA, photophobia, or red flags
- Evaluate cornea, anterior chamber
7. Management
Principles
- Most viral conjunctivitis is self-limited: Supportive care
- Antibiotics for bacterial: Topical drops or ointment
- Hyperacute gonococcal is an emergency: Systemic antibiotics + ophthalmology
- Anti-allergy drops for allergic: Antihistamine/mast cell stabilizer
- Infection control: Hand hygiene, avoid sharing towels
Viral Conjunctivitis (Supportive)
| Intervention | Details |
|---|---|
| Cold compresses | Symptomatic relief |
| Artificial tears | Lubrication |
| Hand hygiene | Prevent spread |
| Avoid contact lens wear | Until resolved |
Duration: 1-3 weeks; self-limited
Bacterial Conjunctivitis (Topical Antibiotics)
First-Line:
| Agent | Dose | Duration |
|---|---|---|
| Erythromycin ointment 0.5% | Apply to conjunctiva QID | 5-7 days |
| Polymyxin B/Trimethoprim drops | 1 drop QID | 5-7 days |
| Fluoroquinolone drops (ciprofloxacin, ofloxacin) | 1 drop QID | 5-7 days |
Contact Lens Wearers:
- Use fluoroquinolone (cover Pseudomonas)
- Remove contact lenses
Gonococcal Conjunctivitis (Hyperacute)
EMERGENCY: Can perforate cornea within 24-48 hours
| Intervention | Details |
|---|---|
| Ceftriaxone | 1 g IM × 1 |
| + Azithromycin | 1 g PO × 1 |
| Saline irrigation | Hourly to remove discharge |
| Ophthalmology | Urgent referral |
| Treat sexual partners | |
| Screen for other STIs | HIV, syphilis, chlamydia |
Chlamydial Conjunctivitis
| Intervention | Details |
|---|---|
| Azithromycin | 1 g PO × 1 |
| Doxycycline | 100 mg BID × 7 days (alternative) |
| Treat sexual partners |
Allergic Conjunctivitis
| Intervention | Details |
|---|---|
| Cold compresses | Symptomatic relief |
| Artificial tears | Wash away allergens |
| Antihistamine drops | Olopatadine, ketotifen |
| Mast cell stabilizers | Cromolyn |
| Avoid allergens | If identified |
Neonatal Conjunctivitis (Ophthalmia Neonatorum)
EMERGENCY in newborns
| Etiology | Treatment |
|---|---|
| Gonococcal | Ceftriaxone 25-50 mg/kg IV/IM × 1 + Saline irrigation |
| Chlamydial | Erythromycin 50 mg/kg/day ÷ QID × 14 days |
| Urgent ophthalmology | Always |
8. Complications
Disposition
Discharge Criteria
- Uncomplicated conjunctivitis (viral, mild bacterial, allergic)
- No red flags
- Vision normal
- Able to administer medications
- Follow-up if worsening
Referral to Ophthalmology
| Indication | Urgency |
|---|---|
| Gonococcal conjunctivitis | Urgent |
| Decreased visual acuity | Same day |
| Corneal involvement | Same day |
| Suspected keratitis or iritis | Same day |
| Neonatal conjunctivitis | Urgent |
| Contact lens + red eye (keratitis concern) | Same day |
| No improvement in 5-7 days | Non-urgent |
11. Patient/Layperson Explanation
Condition Explanation
- "You have conjunctivitis, commonly called 'pink eye.'"
- "Most cases are caused by viruses and get better on their own in 1-2 weeks."
- "It is very contagious, so wash your hands frequently."
Home Care
- Apply warm or cold compresses
- Use artificial tears for comfort
- Use prescribed eye drops as directed
- Wash hands frequently
- Don't share towels, pillows, or eye makeup
- Avoid wearing contact lenses until healed
- Stay home from work/school if contagious
Warning Signs to Return
- Vision changes
- Worsening pain or photophobia
- Swelling around the eye
- Not improving in 5-7 days
- Symptoms spreading to other eye rapidly
9. Prognosis & Outcomes
Special Populations
Contact Lens Wearers
- High risk for Pseudomonas keratitis
- Remove lenses immediately
- Use fluoroquinolone drops
- Low threshold for ophthalmology referral
Neonates
- Ophthalmia neonatorum is serious
- Can lead to blindness (gonococcal)
- Test and treat for GC and chlamydia
- Urgent ophthalmology
Immunocompromised
- Consider broader differential (HSV, CMV)
- Lower threshold for specialist referral
Quality Metrics
Performance Indicators
| Metric | Target | Rationale |
|---|---|---|
| Visual acuity documented | 100% | Red flag detection |
| Avoid antibiotics for viral | >0% | Stewardship |
| STI testing for gonococcal | 100% | Comprehensive care |
| Ophthalmology referral for red flags | 100% | Safety |
Documentation Requirements
- Discharge type (watery, purulent)
- Visual acuity
- Red flag assessment
- Treatment and follow-up
10. Evidence & Guidelines
Key Clinical Pearls
Diagnostic Pearls
- Most is viral: Watery discharge, preauricular nodes, URI
- Purulent = Bacterial: Consider antibiotics
- Severe itching = Allergic: Antihistamine drops
- Hyperacute purulent = Gonococcal: Emergency
- Decreased VA or photophobia = More serious: Not simple conjunctivitis
- Contact lens + red eye = Keratitis until proven otherwise
Treatment Pearls
- Viral = Supportive only: Self-limited
- Bacterial = Topical antibiotics: Erythromycin or fluoroquinolone
- Fluoroquinolone for contact lens wearers: Cover Pseudomonas
- Gonococcal = Ceftriaxone + azithromycin + ophthalmology
- Allergic = Antihistamine/mast cell drops
- Highly contagious: Emphasize hand hygiene
Disposition Pearls
- Most can be discharged: With drops and education
- Ophthalmology for red flags: Decreased VA, corneal involvement
- Urgent for gonococcal or neonatal: Risk of blindness
- Follow-up if no improvement in 5-7 days
12. References
- Azari AA, Barney NP. Conjunctivitis: A Systematic Review of Diagnosis and Treatment. JAMA. 2013;310(16):1721-1729.
- Hovding G. Acute bacterial conjunctivitis. Acta Ophthalmol. 2008;86(1):5-17.
- American Academy of Ophthalmology. Conjunctivitis Preferred Practice Pattern. 2018.
- Leibowitz HM. The Red Eye. N Engl J Med. 2000;343(5):345-351.
- Sheikh A, et al. Antibiotics versus placebo for acute bacterial conjunctivitis. Cochrane Database Syst Rev. 2012;9:CD001211.
- Workowski KA, et al. Sexually Transmitted Infections Treatment Guidelines, 2021. MMWR Recomm Rep. 2021;70(4):1-187.
- Taylor HR. Diagnosis and management of acute conjunctivitis. Aust Prescr. 2017;40(4):128-131.
- UpToDate. Conjunctivitis in adults. 2024.