What is the differential diagnosis for a 3-year-old child with bilateral eye pain and sore throat?

Differential Diagnosis for 3-Year-Old with Bilateral Eye Pain and Sore Throat

The most critical diagnoses to rule out immediately are Kawasaki disease, adenoviral pharyngoconjunctivitis, and group A streptococcal pharyngitis with concurrent bacterial conjunctivitis, as these can lead to serious morbidity if missed.

Life-Threatening and High-Morbidity Conditions (Rule Out First)

Kawasaki Disease

• Must be considered urgently in any child with bilateral conjunctival injection and pharyngeal erythema, as delayed diagnosis leads to coronary artery aneurysms in 25% of untreated cases 1
• Look for: fever ≥5 days, bilateral bulbar conjunctival injection WITHOUT exudate (painless), erythema and cracking of lips, strawberry tongue, diffuse pharyngeal erythema, polymorphous rash, extremity changes, and cervical lymphadenopathy 1
• Key distinguishing feature: The conjunctivitis in Kawasaki disease is typically painless and spares the limbus, whereas bacterial conjunctivitis causes true eye pain 1
• Requires immediate cardiology consultation and IVIG treatment if diagnosed 1

Bacterial Conjunctivitis with Pharyngitis (Concurrent Infection)

• Group A streptococcal pharyngitis can occur simultaneously with bacterial conjunctivitis, particularly Haemophilus influenzae or Streptococcus pneumoniae 1
• Presents with purulent eye discharge, mattering of eyelids, true eye pain, and exudative pharyngitis 2
• Critical action: Examine cornea with fluorescein staining to rule out corneal involvement, which can progress rapidly 3
• If concurrent purulent conjunctivitis and pharyngitis, prescribe amoxicillin-clavulanate (not plain amoxicillin) at 80-90 mg/kg/day divided twice daily for broader β-lactamase coverage 4
• GAS can rarely cause endophthalmitis with devastating vision loss, though this typically requires bacteremia 5

Common Infectious Causes

Adenoviral Pharyngoconjunctivitis

• Most common viral cause combining both symptoms in children, often occurring in school outbreaks 1
• Presents with watery discharge (not purulent), follicular conjunctivitis on inferior tarsal conjunctiva, pharyngitis, and often concurrent upper respiratory symptoms 1
• Eye pain is typically described as gritty or burning rather than sharp 2
• Self-limited within 5-14 days, treatment is supportive only 1
• Highly contagious: child should avoid school until symptoms improve 6

Herpes Simplex Virus Conjunctivitis with Pharyngitis

• Can present bilaterally in young children, though usually unilateral 1
• Look for vesicular rash or ulceration on eyelids as distinctive sign 1
• Requires immediate ophthalmology referral as it can progress to keratitis, corneal scarring, and perforation 3
• Fluorescein staining shows dendritic (branching) corneal ulcers 1

Varicella Zoster Virus (Primary Chickenpox)

• Primary infection can cause bilateral conjunctivitis with pharyngitis 1
• Look for characteristic vesicular rash on body, vesicles at limbus 1
• Usually self-limited but can cause corneal scarring 1

Less Common but Important Considerations

Allergic Conjunctivitis with Concurrent Viral Pharyngitis

• Seasonal allergic conjunctivitis presents with bilateral itching (not pain), watery discharge, and can coincide with viral upper respiratory infection causing sore throat 2
• Key distinction: True eye pain is uncommon in allergic conjunctivitis; itching predominates 2

Parinaud Oculoglandular Syndrome

• Presents with unilateral (rarely bilateral) granulomatous follicular conjunctivitis and ipsilateral preauricular lymphadenopathy 3
• Caused by cat scratch disease, tularemia, or sporotrichosis 3
• Ask about cat exposure or outdoor activities 3

Critical Examination Steps

Immediate Assessment Required

• Visual acuity testing using age-appropriate methods (HOTV chart or tumbling E for 3-year-old) 1
• Fluorescein staining of cornea to detect corneal involvement—mandatory in any purulent conjunctivitis 3
• Red reflex examination to rule out intraocular pathology 1
• Throat examination for exudates, erythema, petechiae on palate 7
• Skin examination for rash, vesicles, or Kawasaki-associated findings 1
• Temperature and duration of fever if present 1

Red Flags Requiring Immediate Ophthalmology Referral

• Moderate to severe eye pain (not just discomfort) 6
• Corneal involvement on fluorescein examination 3
• Visual acuity changes 6
• Eyelid vesicles suggesting HSV 6
• Marked eyelid edema with purulent discharge (consider gonococcal, though rare in this age without sexual abuse) 3

Practical Management Algorithm

If fever ≥5 days + bilateral non-purulent conjunctivitis + pharyngeal erythema + any other Kawasaki criteria:

• Immediate pediatric cardiology referral for echocardiogram and IVIG consideration 1

If purulent discharge + pharyngitis:

• Fluorescein stain cornea 3
• If cornea clear: Amoxicillin-clavulanate 80-90 mg/kg/day divided BID for 10 days 4
• Add topical fluoroquinolone drops (ciprofloxacin or ofloxacin) 4
• Reassess in 48-72 hours; if worsening, refer to ophthalmology 4

If watery discharge + follicular conjunctivitis + URI symptoms:

• Supportive care for presumed adenoviral infection 1
• Counsel on contagion and hand hygiene 6
• Follow up in 3-4 days if not improving 6

If vesicular rash on eyelids:

• Immediate ophthalmology referral for HSV evaluation 6

Common Pitfalls to Avoid

• Do not dismiss bilateral conjunctival injection as "just viral" without carefully evaluating for Kawasaki disease, especially if fever is present 1
• Do not prescribe plain amoxicillin for concurrent conjunctivitis and pharyngitis; use amoxicillin-clavulanate for β-lactamase coverage 4
• Do not skip fluorescein examination in any case with purulent discharge, as corneal involvement changes management urgently 3
• Do not assume allergic conjunctivitis if true pain (not itching) is present 2