Pediatric emergency medicine trisk 1012

present with a red, painful, watery eye. The conjunctival injection is usually
sectoral. Presence of concomitant vesicular lesions in the eyelid region helps raise
concern for HSV infection, however skin lesions need not be present. Patients
with herpes zoster ophthalmicus experience pain, often followed by development
of vesicular lesions in the involved dermatome (i.e., ophthalmic division of
trigeminal nerve), which is commonly associated with significant lid swelling and
pain ( Fig. 123.9 ). Corneal involvement may occur 5 to 7 days after skin lesions
are seen.
Airborne or contact allergic conjunctivitis is characterized by hyperacute
conjunctival injection associated with watery tearing and a blister-like swelling of
the conjunctiva (chemosis) ( Fig. 123.10 ). Itching is often a prominent symptom.
The history may reveal recent exposure to an environmental allergen (e.g., cat
dander). Seasonal allergic conjunctivitis, a recurrent reaction to outdoor pollens,
typically has a less dramatic onset. Patients may have a history of atopy such as
allergic rhinitis, asthma, or eczema.
TABLE 123.1
DIFFERENTIAL DIAGNOSIS OF CONJUNCTIVITIS


FIGURE 123.7 Patient with right epidemic keratoconjunctivitis infection. Note the lid
swelling, red eye, and absence of purulent discharge. Patient also has right preauricular
adenopathy (not visible). Note the early injection of left eye, representing sequential
involvement.

Clinical Assessment. No child should be diagnosed or treated for conjunctivitis
without a careful examination. Although conjunctivitis is characterized by ocular
erythema, not all patients with a red eye have conjunctivitis. Various ophthalmic
conditions, as well as many systemic processes, can be associated with a red eye.
One should also be weary of making this diagnosis in a patient with recent ocular
trauma. Chapter 114 Ocular Trauma outlines the evaluation and differential
diagnosis of this finding. Signs and symptoms not typically associated with

conjunctivitis that should prompt a search for a more serious condition include
reduced visual acuity, significant ocular pain and/or photophobia, corneal
opacities, and significant foreign-body sensations. Fluorescein instillation is
recommended to fully evaluate the ocular surface in these cases. Characteristic
dendritic staining patterns can be seen on the cornea or conjunctiva in herpetic
infections ( Fig. 123.11 ). Ophthalmic consultation is indicated in suspected HSV
ocular disease. The clinician should also be wary of making the diagnosis of
conjunctivitis in contact lens wearers. These patients are at risk for inflammation
and ulceration of the cornea known as bacterial keratitis. A bacterial corneal ulcer
will appear as a white spot in the normally clear cornea associated with
conjunctival injection, foreign body sensation or pain, photophobia, and
decreased vision (see Chapter 27 Eye: Red Eye ). This is a rapidly progressing


sight-threatening condition that requires immediate consultation with an
ophthalmologist.

FIGURE 123.8 Patient with herpes simplex infection limited to the eyelids. Conjunctiva appear
white/noninjected (absence of corneal and conjunctival involvement should always be
confirmed by fluorescein examination).


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.