These two forms of conjunctivitis, as well as other forms of bacterial conjunctivitis (S aureus, Escherichia coli , Pseudomonas aeruginosa ), can be difficult to distinguish clinically and may coexist FIGURE 123.6 Neonatal gonorrheal conjunctivitis Note the dramatic lid swelling and severe purulent discharge In children beyond the neonatal period, a wide range of organisms, both viral and bacterial, as well as chlamydia, can cause conjunctivitis Clinically, these entities may be indistinguishable Table 123.1 is designed to give some additional help in differentiating causes of conjunctivitis In general, purulence is more characteristic of bacterial infections, whereas clear serous discharge is more characteristic of viral infection Bacterial and viral conjunctivitis can be associated with otitis media and pharyngitis, respectively Although both viral and bacterial conjunctivitis may be unilateral or bilateral, a history of multiple infected contacts, or consecutive involvement of one eye and then the other, argues in favor of a viral etiology Likewise, dramatic lid swelling associated with preauricular adenopathy, mucoid or serous discharge, and perhaps an uncomfortable, sandy, foreign-body sensation is strongly suggestive of epidemic keratoconjunctivitis secondary to adenovirus This fulminant viral infection is usually easy to recognize ( Fig 123.7 ) Both HSV and varicella zoster virus can cause infections limited to the skin surrounding the eye ( Fig 123.8 ) or may also involve the cornea and/or conjunctiva Patients with ocular HSV infection usually