Conjunctivitis is inflammation of the mucous membrane that lines the surface of the eyeball and inner eyelids. It may be acute or chronic. Most cases are due to viral or bacterial (including gonococcal and chlamydial) infection. Other causes include keratoconjunctivitis sicca, allergy, chemical irritants, and trauma. The mode of transmission of infectious conjunctivitis is usually via direct contact of contaminated fingers or objects to the fellow eye or to other persons. It may also be spread through respiratory secretions or contaminated eye drops.
Conjunctivitis must be differentiated from acute uveitis, acute glaucoma, and corneal disorders (Table 7–1).
et al. Bedside diagnosis of the ‘red eye’: a systematic review. Am J Med. 2015 Nov;128(11):1220–4.e1.
Adenovirus is the most common cause of viral conjunctivitis. There is usually sequential bilateral disease with copious watery discharge and a follicular conjunctivitis. Infection spreads easily. Epidemic keratoconjunctivitis, which may result in decreased vision from corneal subepithelial infiltrates, is usually caused by adenovirus types 8, 19, and 37. The active viral conjunctivitis lasts up to 2 weeks, with the immune-mediated keratitis occurring later. Infection with adenovirus types 3, 4, 7, and 11 is typically associated with pharyngitis, fever, malaise, and preauricular adenopathy (pharyngoconjunctival fever). The disease usually lasts 10 days. Contagious acute hemorrhagic conjunctivitis (see Chapter 32) may be caused by enterovirus 70 or coxsackievirus A24. Viral conjunctivitis from herpes simplex virus (HSV) is typically unilateral and may be associated with lid vesicles.
Except for HSV infection for which treatment with topical (eg, ganciclovir 0.15% gel) and/or systemic (eg, oral acyclovir, valacyclovir) antivirals is recommended (Table 32–1), there is no specific treatment for contagious viral conjunctivitis. Artificial tears and cold compresses may help reduce discomfort. The use of topical antibiotics and steroids in the acute infection is discouraged. Frequent hand and linen hygiene is encouraged to minimize spread.
et al; American Academy of Ophthalmology Preferred Practice Pattern Cornea and External Disease Panel. Conjunctivitis Preferred Practice Pattern®
. Ophthalmology. 2019 Jan;126(1):P94–P169.
2. BACTERIAL CONJUNCTIVITIS
The organisms isolated most commonly in bacterial conjunctivitis are staphylococci, including methicillin-resistant S aureus (MRSA); streptococci, particularly Streptococcus pneumoniae; Haemophilus species; Pseudomonas; and Moraxella. All may produce a copious purulent discharge. There is no blurring of vision and only mild discomfort. In severe (hyperpurulent) cases, examination of stained conjunctival scrapings and cultures is recommended, particularly to identify gonococcal infection that requires emergent treatment.
The disease is usually self-limited, lasting about 10–14 days if untreated. Most topical antibiotics hasten clinical remission. This infection is typically self-limited and benign, and no topical antibiotic has proven superiority over another.
A. Gonococcal Conjunctivitis