Overview
Definition:
Conjunctivitis, commonly known as 'red eye', is inflammation of the conjunctiva, the thin transparent membrane covering the white part of the eye and the inner surface of the eyelids
It can be caused by various agents, including allergens and bacteria, leading to distinct clinical presentations and management strategies in pediatric patients
Differentiating between allergic and bacterial etiologies is crucial for appropriate treatment and preventing complications.
Epidemiology:
Conjunctivitis is one of the most common eye conditions encountered in pediatric practice, accounting for a significant percentage of outpatient visits
Bacterial conjunctivitis is more common in younger children, while allergic conjunctivitis is more prevalent in older children and adolescents, often associated with a history of atopy
Seasonal and perennial allergic conjunctivitis are common forms.
Clinical Significance:
Accurate differentiation between allergic and bacterial conjunctivitis is vital to avoid unnecessary antibiotic use in allergic cases, which contributes to antimicrobial resistance
Conversely, delayed or inadequate antibiotic treatment in bacterial conjunctivitis can lead to serious complications such as keratitis, corneal ulceration, and vision loss
Effective management ensures symptomatic relief, prevents spread, and preserves visual acuity.
Clinical Presentation
Symptoms:
Allergic conjunctivitis: Intense itching (pruritus) is the hallmark
Watery discharge
Redness
Tearing
Bilateral involvement is common
Symptoms often seasonal or perennial
Photophobia may be present
Other atopic symptoms like rhinitis or asthma may co-exist
Bacterial conjunctivitis: Redness
Purulent or mucopurulent discharge (often thick, sticky, and yellow/green)
Eyelid matting, especially upon waking
Gritty sensation
Foreign body sensation
Unilateral or bilateral involvement
Pain is usually mild
severe pain suggests keratitis.
Signs:
Allergic conjunctivitis: Bilateral conjunctival injection (hyperemia)
Chemosis (conjunctival edema)
Eyelid edema
Cobblestoning of the palpebral conjunctiva (especially in vernal keratoconjunctivitis)
Watery discharge
Papillary hypertrophy is common
Bacterial conjunctivitis: Conjunctival injection
Purulent discharge
Eyelid edema
Possibly preauricular lymphadenopathy
Corneal involvement (keratitis) may present as punctate epithelial erosions or focal infiltrates.
Diagnostic Criteria:
Diagnosis is primarily clinical
No specific laboratory criteria are universally established for routine diagnosis, but history and physical examination findings are key
A conjunctival swab for Gram stain and culture may be considered in severe, recurrent, or unresponsive bacterial cases, or to identify specific pathogens.
Diagnostic Approach
History Taking:
Key history points: Onset and duration of symptoms
Nature of discharge (watery vs
purulent)
Presence of itching
Bilateral vs
unilateral involvement
History of allergies, asthma, or eczema
Seasonal variation
Recent exposure to ill individuals
Contact lens wear
Use of eye drops
Red flags: Severe pain, photophobia, decreased vision, purulent discharge, recent trauma, foreign body sensation.
Physical Examination:
Systematic examination: Assess visual acuity for both eyes
Evert eyelids to examine the conjunctiva and look for discharge, follicles, papillae, or cobblestoning
Examine the cornea for infiltrates or opacities
Assess for preauricular lymphadenopathy
Check for signs of associated systemic conditions.
Investigations:
Generally not required for typical cases
Conjunctival swab: For Gram stain and culture/sensitivity if bacterial infection is suspected, severe, or not responding to empiric treatment
Eosinophil count in conjunctival scrapings (Wright stain) can support allergic etiology, but is rarely performed in routine practice
Polymerase Chain Reaction (PCR) for specific pathogens (e.g., Chlamydia, Adenovirus) may be considered in specific situations.
Differential Diagnosis:
Viral conjunctivitis: Often watery discharge, preauricular lymphadenopathy, follicular conjunctivitis
Irritant conjunctivitis: History of exposure to irritants
Dry eye disease
Foreign body
Corneal abrasion/ulcer
Uveitis
Orbital cellulitis.
Management
Initial Management:
Allergic conjunctivitis: Avoidance of identified allergens
Cool compresses
Artificial tears for symptomatic relief
Bacterial conjunctivitis: Emphasize meticulous eyelid hygiene and frequent cleaning of discharge to prevent spread and crusting
Parental education on transmission prevention (handwashing, avoiding sharing towels/pillows).
Medical Management:
Allergic conjunctivitis: Topical antihistamines (e.g., olopatadine, ketotifen) are first-line
Mast cell stabilizers (e.g., cromolyn sodium, lodoxamide) can be used prophylactically or adjunctively
Topical corticosteroids (e.g., fluorometholone, loteprednol) may be used for severe inflammation but require careful monitoring for side effects (glaucoma, cataracts) and are generally reserved for specialist use
Oral antihistamines may be considered for associated systemic symptoms
Bacterial conjunctivitis: Topical antibiotics are the mainstay
Common choices include: Polymyxin B/trimethoprim drops (e.g., maxitrol for suspected pseudomonas in neonates, but generally not first-line in older children), Erythromycin ointment (particularly for neonates and Chlamydia), fluoroquinolones (e.g., moxifloxacin, ofloxacin - used judiciously due to resistance concerns), or macrolides (e.g., azithromycin drops)
Treatment duration is typically 5-7 days
For neonates, consider gonococcal and chlamydial causes requiring systemic therapy.
Surgical Management:
Not typically indicated for either condition unless there are specific complications like corneal perforation in severe bacterial keratitis.
Supportive Care:
Allergic conjunctivitis: Education on allergen avoidance and proper use of eye drops
Frequent lubrication with artificial tears
Bacterial conjunctivitis: Frequent cleaning of discharge with clean, moist cloths or cotton balls, used once and then discarded
Encouraging frequent handwashing for the child and caregivers
Keeping the child home from school or daycare until 24 hours after starting antibiotic treatment and discharge has resolved to prevent spread.
Complications
Early Complications:
Allergic conjunctivitis: Severe discomfort, eyelid swelling, transient blurring of vision
Bacterial conjunctivitis: Corneal ulceration, keratitis, endophthalmitis (rare but severe), dacryocystitis, preseptal or orbital cellulitis, preauricular lymphadenopathy.
Late Complications:
Allergic conjunctivitis: Chronic allergic eye disease, eyelid scarring (in severe cases)
Bacterial conjunctivitis: Corneal scarring leading to permanent vision impairment, chronic conjunctival changes.
Prevention Strategies:
Allergic conjunctivitis: Allergen avoidance, regular use of prophylactic topical agents if triggers are known
Bacterial conjunctivitis: Strict hand hygiene, avoiding sharing personal items, prompt treatment of infections, education on safe contact lens wear (though less common in young children).
Prognosis
Factors Affecting Prognosis:
Allergic conjunctivitis: Severity of allergy, adherence to treatment, allergen avoidance
Bacterial conjunctivitis: Promptness and adequacy of antibiotic treatment, presence and severity of corneal involvement, virulence of the bacterial pathogen, and host immune status.
Outcomes:
Allergic conjunctivitis: Generally excellent prognosis with appropriate management, symptoms resolve
Bacterial conjunctivitis: Good prognosis with timely and effective antibiotic therapy
Most cases resolve without sequelae
Significant visual impairment or loss can occur with untreated or severe cases, especially with corneal involvement.
Follow Up:
Allergic conjunctivitis: Follow-up usually only if symptoms persist, worsen, or if steroid drops are used
Bacterial conjunctivitis: Follow-up recommended if symptoms do not improve within 48-72 hours of starting treatment, or if any signs of corneal involvement are present
Routine follow-up after resolution of uncomplicated cases is generally not necessary.
Key Points
Exam Focus:
Key differentiator: Itching is predominant in allergic conjunctivitis
discharge is predominant and purulent in bacterial
Cobblestoning of palpebral conjunctiva points to allergic
Matting of eyelids upon waking suggests bacterial
Neonatal conjunctivitis requires prompt evaluation for gonococcal and chlamydial etiologies
Broad-spectrum topical antibiotics for bacterial conjunctivitis
Avoid steroids in suspected bacterial keratitis.
Clinical Pearls:
Always evert the eyelids to fully assess the conjunctiva and cornea
Educate parents on meticulous hygiene and handwashing for bacterial conjunctivitis to prevent spread
Counsel patients on the chronicity of allergic conjunctivitis and the importance of consistent management and allergen avoidance.
Common Mistakes:
Treating allergic conjunctivitis with antibiotics unnecessarily
Prescribing topical corticosteroids empirically for all red eyes without ruling out bacterial keratitis or herpetic infection
Underestimating the severity of bacterial conjunctivitis and its potential for corneal complications
Inadequate parental education on hygiene and transmission prevention for bacterial conjunctivitis.