A 6-year-old child presents with acute onset of bilateral conjunctival injection, purulent discharge, and eyelid swelling for 3 days. The child attends school and several classmates have similar symptoms. What is the most common bacterial cause of acute purulent conjunctivitis in children in India?

Explanation

## Most Common Bacterial Cause of Acute Purulent Conjunctivitis in Children **Key Point:** *Haemophilus influenzae* (non-typeable strains) is the most common bacterial cause of acute purulent conjunctivitis in children, including the school-age group in India, accounting for approximately 30–40% of cases. ### Epidemiology (Age-Specific) | Age Group | Most Common Cause | |-----------|-------------------| | Neonates (0–28 days) | *N. gonorrhoeae*, *C. trachomatis* | | Infants & Children (6 mo–10 yr) | **H. influenzae** (non-typeable) | | Adults | *S. pneumoniae*, *S. aureus* | - *H. influenzae* is the leading pediatric cause worldwide and in India (Khurana Comprehensive Ophthalmology, 6th ed., Ch. 3) - *S. pneumoniae* is a close second in children and the predominant cause in adults — an important distinction - Highly contagious; spreads rapidly in schools and daycare via hand contact and fomites ### Clinical Features of H. influenzae Conjunctivitis | Feature | *H. influenzae* | *S. pneumoniae* | *N. gonorrhoeae* | |---------|-----------------|-----------------|------------------| | **Onset** | Acute (2–3 days) | Acute | Hyperacute (< 24 hr) | | **Discharge** | Mucopurulent | Purulent | Profuse, purulent | | **Eyelid edema** | Mild–moderate | Moderate | Severe | | **Chemosis** | Present | Present | Marked | | **Preauricular LN** | Absent | Absent | Absent | | **Gram stain** | Pleomorphic gram-negative coccobacilli | Gram-positive diplococci | Gram-negative diplococci | **High-Yield:** *H. influenzae* conjunctivitis often co-presents with **otitis media** or **upper respiratory tract infection** — a classic association tested in NEET PG/INI-CET. ### Microbiology Note - Non-typeable *H. influenzae* (NTHi) strains are the relevant pathogens here; they possess a **poorly immunogenic or absent polysaccharide capsule**, making them non-typeable by standard antisera — they are less invasive but highly mucosal-pathogenic. (This is distinct from typeable strains such as Hib, which have a well-defined capsule.) - Gram stain: **pleomorphic gram-negative coccobacilli** — a useful diagnostic clue. ### Why the Other Options Are Incorrect - **A) N. gonorrhoeae** — causes hyperacute conjunctivitis, primarily in neonates (ophthalmia neonatorum) or sexually active adults; not the most common in school-age children. - **B) S. pneumoniae** — most common in adults; second most common in children; not the leading pediatric cause. - **C) Pseudomonas aeruginosa** — associated with contact lens wearers and nosocomial infections; not a common cause of community-acquired pediatric conjunctivitis. ### Treatment - **Topical fluoroquinolones** (ofloxacin, moxifloxacin) — first-line - **Oral amoxicillin-clavulanate or cephalosporins** if concurrent otitis media or systemic involvement **Clinical Pearl:** School-age child + bilateral purulent conjunctivitis + school outbreak + concurrent otitis media → *Haemophilus influenzae* (non-typeable) is the most likely bacterial cause. [cite: Khurana Comprehensive Ophthalmology, 6th ed., Ch. 3; Parson's Diseases of the Eye, 22nd ed.]