Red Eye

Cynthia J. Mollen

INTRODUCTION

Red eye may refer to erythema of the ocular adnexa, conjunctiva, sclera, or cornea, or inflammation of deeper structures.

DIFFERENTIAL DIAGNOSIS LIST

Ocular Adnexa

Infectious Causes
- Hordeolum and chalazion
- Dacryocystitis
- Molluscum contagiosum
- Blepharitis
- Phthiriasis (louse)
- Frontal sinus infection or other sinusitis
- Periostitis of orbital bones
- Orbital cellulitis, periorbital cellulitis
- Dental abscess
Neoplastic Causes
- Neuroblastoma
- Leukemia
- Neurofibroma
Traumatic Causes
- Insect bites
- Basilar skull fracture
- Trauma to eyelid or nose
Miscellaneous Causes
Frequent eye rubbing
Cavernous sinus thrombosis
Prolonged crying
Contact dermatitis
Seborrhea

Conjunctiva

Infectious Causes
- Bacteria
- Viruses
- Fungi
- Protozoans
- Helminths—onchocerciasis (river blindness)
Toxic Causes
- Atropine, scopolamine
- Irritants—makeup, smoke, smog, chemicals, contact lenses, caterpillar hair, wind, ultraviolet light, tobacco
Neoplastic Causes
- Orbital tumors—retinoblastoma
Traumatic Causes
- Foreign body
- Entropion, ectropion
- Child abuse
- Blunt or penetrating trauma
- Traumatic glaucoma
- Subconjunctival hemorrhage
Immunologic Causes
- Allergic/inflammatory conjunctivitis
- Keratoconjunctivitis sicca and other dry eye disorders
- Nasal inflammation
- Sjögren syndrome and other collagen vascular diseases
- Kawasaki syndrome
- Stevens-Johnson syndrome
- Inflammatory bowel disease
- Juvenile rheumatoid arthritis
- Graves disease
Miscellaneous Causes
- Bone marrow transplant
- Ectodermal dysplasia
- Subconjunctival hemorrhage (secondary to severe cough, bacteremia, blood dyscrasia, or vomiting)

Cornea

Infectious Causes
- Keratitis
- Syphilis
Traumatic Causes
- Contact lenses
- Corneal ulcer
- Corneal abrasion
- Chemical irritant

Uveal Tract

Iridocyclitis
Reiter syndrome

Sclera

Episcleritis
Scleritis
Collagen vascular disease

Pupil

Hyphema
Globe
Glaucoma

DIFFERENTIAL DIAGNOSIS DISCUSSION

Neonatal Conjunctivitis

Etiology

Neonatal conjunctivitis is most often secondary to infection or chemical irritation.

Infection. Causes of infectious conjunctivitis in the neonates include sexually transmitted and nonsexually transmitted organisms. Sexually transmitted agents, in order of decreasing frequency, are Chlamydia trachomatis, Neisseria gonorrhoeae, and herpes simplex virus (HSV), usually type 2. Staphylococcus aureus is the most common nonsexually transmitted infectious pathogen. Other bacterial causes include enteric Gram-negative rods.
Chemical irritation. Silver nitrate is the most common cause of neonatal chemical conjunctivitis, although other antibiotics used for prophylaxis can also cause conjunctivitis.

Clinical Features

Conjunctivitis that presents in the first 24 hours of life is most likely secondary to chemical irritation, unless there was prolonged rupture of membranes before delivery.

Gonococcal conjunctivitis, which presents 2 to 6 days after birth, is an acute to hyperacute infection that causes edema of the eyelids and conjunctiva (chemosis), local pain, and a copious purulent discharge. Swelling and discharge can be so extensive that the orbit is difficult to view. Often there is a palpable preauricular node, a finding otherwise uncommon in bacterial conjunctivitis.
Chlamydial conjunctivitis has a slightly later onset than gonococcal conjunctivitis but can be symptomatic as early as 4 to 5 days after birth. Modest purulent drainage and mild-to-moderate inflammation are seen. As with gonococcal conjunctivitis, the preauricular lymph node may be tender.
Herpes simplex conjunctivitis is associated with clusters of vesicles on the face, eyelids, and mucous membranes.

Evaluation

Bacterial culture, including chocolate agar or Thayer-Martin plates and Gram stain of the purulent material, should be obtained. In up to 95% of cases of gonococcal conjunctivitis, Gram-negative intracellular diplococci are identified by Gram stain.

Chlamydia culture should be obtained on conjunctival scrapings (not purulent material) using a Dacron-tipped swab. Nucleic acid amplification techniques can be used to identify both the organisms in laboratories with these testing capabilities. In patients with suspected herpes simplex conjunctivitis, conjunctival scrapings reveal mononuclear cells and giant multinucleated epithelial cells.

Treatment

Chlamydial conjunctivitis. Hospitalization is not necessary. Treatment consists of 14 days of oral erythromycin combined with topical erythromycin.
Gonococcal conjunctivitis. Hospitalization and consultation with an ophthalmologist are required. The eye should be irrigated every 1 to 2 hours to reduce bacterial load and local irritation. Improperly treated gonococcal conjunctivitis can quickly damage vision. Intravenous therapy for 7 days is indicated for disseminated infection, and up to 14 days for meningitis; one dose is adequate for isolated conjunctivitis. Cefotaxime or ceftriaxone are appropriate until sensitivities are known; use ceftriaxone with caution in patients with hyperbilirubinemia.
Herpes simplex conjunctivitis. Patients must be followed by an ophthalmologist to minimize the chances of permanent scarring and damage to vision.

Infectious Conjunctivitis (Outside the Neonatal Period)

Etiology

The most common bacterial cause of conjunctivitis is S. aureus, which affects all age groups. Haemophilus influenzae and Streptococcus pneumoniae are common causes of conjunctivitis in young children. Adolescents can also present with gonococcal conjunctivitis secondary to sexual contact.

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