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July 2002 Many infectious diseases or processes may affect a child’s eye and require a topically applied antibiotic solution or ointment. Among the most common is conjunctivitis, also referred to as “pink eye” or “red eye.” Because of its commonality and the large number of antimicrobial products available to treat conjunctivitis, this month’s column will focus on the treatment of conjunctivitis with topically applied antimicrobial agents.
While numerous causes of conjunctivitis exist in children, infectious etiologies due to viral or bacterial pathogens are common. It is difficult to clinically differentiate between viral and bacterial conjunctivitis, although a patient’s presentation may be helpful. Purulence (especially unilateral) in the affected eye(s) may indicate a bacterial cause, while mucopurulence or a mucoid discharge may be more indicative of a viral etiology. A viral etiology may also be more likely with concomitant lymphadenopathy. Common viral pathogens include adenovirus, enteroviruses or herpes simplex virus (HSV). Common bacterial pathogens include nontypable Haemophilus influenzae or Streptococcus pneumoniae. Other pathogens in the neonatal period include Neisseria gonorrhoeae or Chlamydia trachomatis. Preschool children are more prone to bacterial pathogens, while school-age children are more prone to viral pathogens. A unique syndrome termed the conjunctivitis-otitis syndrome (CJ-AOM) has been identified with younger age (<3 years) and a history of repeated episodes of acute otitis media (AOM) (>3) within the previous year recognized as risk factors. Nontypable H. influenzae is the predominant pathogen in CJ-AOM. Clinicians should examine the ears of a child (especially one with the above risk factors) who presents with conjunctivitis. Eleven antimicrobial agents are available in solution or ointment form as single entity products. Additional products are available as combinations of antimicrobials or an antimicrobial combined with a corticosteroid. Many are available generically. Clinical differences in efficacy among the available agents are not apparent by controlled clinical trials. Choice of an available product may depend more upon patient acceptance factors (solution vs. ointment) or cost (generic vs. brand). Adverse effects may be more likely with specific agents. Chloramphenicol use has been reported, although rarely (1/40,000), to result in aplastic anemia. The use of neomycin may cause cutaneous allergic reactions. Some products, such as sulfacetamide, may be more likely to cause discomfort upon instillation, although this assessment is anecdotal and not based upon controlled study. Some products, such as the fluoroquinolones, provide a broad spectrum of antimicrobial activity, although this may not be needed. Combination products (eg, polymyxin B/bacitracin) also provide a broad antimicrobial spectrum. Conjunctivitis resulting from infection with C. trachomatis or N. gonorrhoeae should be treated with systemic antibiotics. Several products contain one of four available corticosteroids in addition to an antibiotic. The fear of a significant inflammatory component beyond infectious conjunctivitis may be cause for referral to an ophthalmologist. Use of topically applied corticosteroids may result in significant adverse effects, such as increased intraocular pressure or progression of HSV. The use of oral antibiotics combined with topical therapy in the treatment of concomitant conjunctivitis and AOM, as compared with oral therapy alone, has not been well studied. The use of topical antibiotics and oral therapy has been shown to prevent secondary AOM and has been suggested for children at risk of developing AOM when initially presenting with conjunctivitis. This use should be balanced against the potential for overuse of systemic antibiotics and concomitant risks for promoting further infections with resistant pathogens. The use of a solution or ointment dosage form primarily depends upon patient choice. A therapeutic advantage of either has not been documented. Many patients or caregivers prefer solution drops as they are easier to administer. Ointments have the advantage of increased dwell time within the eye. Appropriate administration technique for antibiotic drops includes placing the drops into the lower eyelid sac followed by closing of the eyes for a minute or longer. An alternative method for younger or uncooperative children involves placing a drop in the inner canthus with the eyes closed and the patient supine. Upon opening the eye, the applied drop should flow into the conjunctival area. Digital pressure on the nasolacrimal duct for several minutes may be helpful in preventing flow of applied solution out of the eye and may reduce systemic absorption by 40%. Application of ointment should occur along the inferior conjunctival fornix or to the outer surface of the lower lid. The use of hand washing cannot be overstressed as a means to prevent spread of infection.
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