FIGURE 123.9 Herpes zoster ophthalmicus Note the eyelid swelling and the presence of vesicular lesions in a dermatomal distribution Triage Considerations Some forms of infectious conjunctivitis are highly contagious and spread by direct contact with the patient’s secretions or with contaminated objects and surfaces Potential cases of conjunctivitis should ideally be identified in triage and appropriate contact precautions should be initiated Proper hand washing is essential to prevent spread Diagnostic Testing In neonates with purulent conjunctivitis, urgent bacterial Gram stain and cultures should be obtained to look for gram-negative diplococci consistent with gonorrhea Chlamydial studies may also be useful in this age group Conjunctival specimens must contain conjunctival cells from an everted eyelid since chlamydia is an obligate intracellular organism Although various methods of detection exist (e.g., nucleic acid amplification tests, antigen detection methods), chlamydial cultures remain the gold standard for diagnosis Outside the neonatal period a diagnosis of conjunctivitis can generally be made on the clinical features alone Studies to determine a causative organism should be reserved for cases of severe inflammation or chronic or recurrent infections Viral culturing is rarely necessary