South African Family Practice 2017; 59(4):22-26 S Afr Fam Pract Open Access article distributed under the terms of the ISSN 2078-6190 EISSN 2078-6204 Creative Commons License [CC BY-NC-ND 4.0] © 2017 The Author(s) http://creativecommons.org/licenses/by-nc-nd/4.0 REVIEW

Diagnosing a : an allergy or an infection?

L Lambert

*Corresponding author, [email protected]

Abstract A red eye is the cardinal sign of ocular inflammation, and is one of the most common ophthalmological complaints. Inflammation of almost any part of the eye, including the lacrimal glands and , or a faulty tear film, can lead to a red eye. The condition is usually benign, self-limiting and can be managed effectively in general practice. While there may be numerous causes of a red eye, is the most common. A thorough patient history and physical examination of the eye are essential in the management of a red eye when differentiating between an allergic and an infectious cause.

Keywords: red eye, allergy, infection, inflammation, conjunctivitis, viral, bacterial

Introduction • Unilateral or bilateral eye involvement

A red eye is caused by the dilation of blood vessels in the eye, • The duration of symptoms and is one of the most common ocular complaints experienced • The type and amount of discharge by patients.1,2 The diagnosis of a red eye may be aided by the • Visual changes differentiation between ciliary and conjunctival injection or redness: • The severity of the pain • Ciliary injection involves branches of the anterior ciliary • arteries, and indicates inflammation of the , or ciliary • The presence of allergies or systemic disease. body The eye examination should include the eyelids, lacrimal sac, • Conjunctival injection mainly affects the posterior conjunctival size and reaction to light, corneal involvement, and the blood vessels. Since these vessels are more superficial than the ciliary arteries, they produce more pronounced redness. pattern and location of hyperaemia. Preauricular lymph node involvement and visual acuity should also be assessed.2 Numerous conditions may be associated with a red eye, including conjunctivitis, , corneal injury, , iritis, Ophthalmologist referral is necessary when there is:3 1 , and a bacterial or viral infection. While the diagnosis • Impaired vision of a red eye can vary from relatively innocuous and trivial • The presence of a foreign body sensation: This is the cardinal conditions to those that are more devastating, conjunctivitis is symptom of an active corneal process. Objective evidence the most common cause of a red eye.2 The focus of this article of a foreign body sensation, in which the patient is unable to is to differentiate between an infectious or an allergic cause of a red eye. spontaneously open the eye or keep it open, suggests corneal involvement, and such patients warrant emergent or urgent Patient evaluation referral. By comparison, many patients report a “scratchy Limited epidemiological data are available on red eyes, nor is feeling,” “grittiness” or a sensation “like sand in my eyes” with there evidence-based guidance as to the management thereof. an allergy, viral conjunctivitis or dry eyes. This is a subjective However, a history and overall patient assessment are useful and foreign body sensation and does not necessarily suggest an confirmatory in the decision to manage or refer.3A thorough active corneal process requiring referral. patient history and eye examination may provide clues to the • Photophobia: This may be present in patients with an active aetiology of a red eye. corneal process. These patients may also have objective signs The history should include questions about:2 of foreign body sensation and require referral.

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Conjunctivitis: the most common cause of a red eye treatment may include the topical administration of aciclovir ointment for the skin lesions.4 Conjunctivitis is the most common cause of a red eye, and is characterised by inflammation of the superficial conjunctival Molluscum contagiosum blood vessels that cover the ocular surface, as well as cellular infiltration and exudation. It must be differentiated on the basis Molluscum contagiosum can cause follicular conjunctivitis, in of aetiology, which can either be infectious, e.g. viral, bacterial or association with an lesion. In most cases, the lesion is a chlamydial; or non-infectious, e.g. allergic.1,2,4 small, pearly umbilicated nodule on or near the lid margin. Multiple lesions may be present, especially in a patient with Viral conjunctivitis human immunodeficiency virus infection. Treatment involves Viral conjunctivitis is characterised by an acute follicular incision and curettage of the symptomatic lesions. The conjunctival reaction, as well as preauricular or submandibular asymptomatic lesions are usually self-limiting if left for long lymphadenopathy.4 Viral conjunctivitis usually spreads through enough.4 direct hand-to-eye contact, medical instruments, swimming pool water or personal items. It is often associated with an Bacterial conjunctivitis upper respiratory infection spread through coughing. In most Bacterial conjunctivitis is highly contagious, and is most cases, the clinical presentation of viral conjunctivitis is mild, with commonly spread through contaminated hand-to-eye contact.2 spontaneous remission after 1-2 weeks. Treatment is supportive, Based on the duration and severity of , and may include cold compresses, ocular decongestants and bacterial conjunctivitis is categorised as hyperacute, acute or artificial tears. Topical antibiotics are rarely necessary because chronic. secondary bacterial infections are uncommon.2 Hyperacute bacterial conjunctivitis To prevent the spread of viral conjunctivitis, patients should be counselled to practise strict hand washing and avoid sharing Hyperacute bacterial conjunctivitis is often associated with personal items which may spread infection. Referral to an Neisseria gonorrhoeae in sexually active adults, while neonates ophthalmologist is necessary if the symptoms do not resolve can acquire it at birth. The infection has a sudden onset, and after 7-10 days, or if there is corneal involvement. Furthermore, rapidly progresses to corneal perforation. Hyperacute bacterial suspected ocular herpetic infection also warrants immediate conjunctivitis is characterised by copious, purulent discharge referral.2 that reforms quickly after it is wiped away, pain, diminished The most common causative viruses include adenovirus, herpes vision and preauricular lymphadenopathy.2,5 Treatment includes 4 simplex and molluscum contagiosum. Viral conjunctivitis caused irrigation of the eye with a saline solution, a single immediate by the adenovirus is highly contagious, whereas conjunctivitis intramuscular injection with ceftriaxone, followed by topical caused by the other viruses is less likely to spread.2 ciprofloxacin.5 Patients need prompt ophthalmological referral Adenovirus conjunctivitis for aggressive management since these bacteria can cause penetration of the intact cornea and lead to abscess formation.2,5 Adenovirus conjunctivitis may present as a mild infection and progress to a more severe syndrome, such as Acute bacterial conjunctivitis pharyngoconjunctival fever or epidemic keratoconjunctivitis. Pharyngoconjunctival fever predominantly affects children, and Acute bacterial conjunctivitis is the most common form of is often accompanied by an upper respiratory tract infection. bacterial conjunctivitis. Acute bacterial conjunctivitis in adults Epidemic keratoconjunctivitis, commonly known as “pink eye”, is often caused by a Staphylococcus aureus infection, whereas is typically not associated with systemic manifestations. These Streptococcus pneumoniae and Haemophilus influenzae infections infections are often bilateral and associated with preauricular are more common pathogens in children.2 The organisms lymphadenopathy. The incubation period is from 7-9 days before causing acute bacterial conjunctivitis may be spread by hand to the onset of symptoms, such as ocular itching, tearing, redness eye contact or by colonisation of the adjacent mucosal tissues, and photophobia. In severe cases, subconjunctival such as the nasal or sinus mucosa. Acute bacterial conjunctivitis may occur, and the cornea may become affected in the second initially presents unilaterally. However, the second eye is often week. Treatment is usually supportive. Cold compresses and affected soon thereafter. A sticky discharge that causes the lubricating eyedrops may be used to relieve discomfort. Topical eyelids to adhere to each other in the morning, as well as a foreign antihistamine eyedrops may be applied to alleviate severe body sensation, are typical symptoms.4 As a result, patients itching.4 often complain of crusting of the eyelids, which results from the Herpes simplex conjunctivitis mucopurulent discharge that causes matting of the .5 Infants and young children are predominantly affected by Acute bacterial conjunctivitis does not affect vision or pupillary primary ocular herpes simplex virus (HSV) infection. It presents reactions. In addition, the cornea and anterior chamber should as a follicular conjunctivitis that manifests as a red, teary eye be clear. However, on examination, generalised redness of the associated with a typical vesicular eruption on the eyelids. 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Chronic bacterial conjunctivitis sexually active patients who have typical signs and symptoms, but do not respond to standard antibiotic treatment, such as Chronic bacterial conjunctivitis is characterised by signs and 2 symptoms that persist for at least four weeks, with frequent chloramphenicol. Treatment includes oral doxycycline to clear relapses. Patients with chronic bacterial conjunctivitis should the genital infection. The patient’s sexual partner should also be be referred to an ophthalmologist.2 In general, bacterial treated.2,6 conjunctivitis is benign and self-limiting and highly responsive to treatment.

Chloramphenicol ointment or drops are effective owing to Allergic conjunctivitis is often associated with allergic rhinitis, their broad-spectrum activity. In addition to topical antibiotic eczema or asthma.2 Acute allergic rhinoconjunctivitis (hay fever) treatment, patients should be made aware of the importance of is the most common form of ocular and nasal allergy.4 Transient proper hygiene and hand washing. Patients should be referred in attacks of itchiness, tears and redness are common symptoms, cases when the conjunctivitis is recurrent or refractory to initial with itching of the eyes being the most apparent feature.2,4 treatment.4 Associated features, such as sneezing and nasal discharge, may Chlamydial conjunctivitis be present. Oedema of the eyelid and chemosis may be present Chlamydia is a common cause of chronic follicular conjunc- in severe cases. Treatment using antihistamine drops provides tivitis.2,4 Chlamydial conjunctivitis should be suspected in symptomatic relief.4

Table I: Differential diagnosis of a red eye due to conjunctivitis2 Condition Signs Symptoms Cause Viral conjunctivitis • Normal vision • Mild to no pain • Adenovirus (most common) • Normal pupil size and reaction • Diffuse hyperaemia • Enterovirus to light • Occasional gritty discomfort, • Varicella-zoster virus • Diffuse conjunctival redness with mild itching • Epstein Barr virus • Preauricular lymphadenopathy • Watery to serous discharge • Herpes simplex virus • Lymphoid follicle on the under • Photophobia (uncommon) • Influenza viruses surface of the eyelid • Often unilateral at onset, with the second eye involved • within 1-2 days • Severe cases may cause subepithelial corneal opacities and pseudomembranes Bacterial conjunctivitis (acute and • Eyelid oedema • Mild to moderate pain, with a Common pathogens in children: chronic) • Preserved visual acuity stinging sensation • Streptococcus pneumoniae • Conjunctival redness • A red eye with a foreign body • Non-typeable Haemophilus • Normal pupil reaction sensation • influenzae • No corneal involvement • Mild to moderate purulent discharge Common pathogen in adults: • Mucopurulent secretions with • Staphylococcus aureus bilateral glued eyes upon awakening (best predictor) Other pathogens: • Staphylococcus spp. • Moraxella spp. • Neisseria gonorrhoeae • Gram-negative organisms, e.g. Escherichia coli • Pseudomonas spp. Bacterial conjunctivitis Chemosis, with possible corneal • Severe pain Neisseria gonorrhoeae (hyperacute) involvement • Copious, purulent discharge • Diminished vision Chlamydial (inclusion • Vision usually preserved • A red, irritated eye Chlamydia trachomatis (serotypes conjunctivitis) • reactive to light • Mucopurulent or purulent D-K) • Conjunctival injections discharge • No corneal involvement • Glued eyes upon awakening • Preauricular lymph node • Blurred vision swelling is sometimes present Allergic • Visual acuity preserved • Bilateral eye involvement • Airborne pollen • Pupils reactive to light • Painless tearing • Dust mites • Conjunctival redness • Intense itching • Animal dander • No corneal involvement • Diffuse redness • Feathers • Large cobblestone papillae • A stringy or ropy watery • Other environmental antigens under the upper eyelid • discharge • Chemosis

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Patient presents with a red eye

Pain

Mild or no pain, with mild blurring Moderate to severe pain or normal vision

Vision loss, disorted pupil and corneal Hyperaemia involvement

Focal Diffuse? Vesicular rash (herpetic keratitis), severe mucopurulent discharge Episcleritis Discharge? (hyperacute bacterial conjunctivitis), keratitis and

No Yes Emergency ophthalmological referral

Continuous Subconjunctival Intermittent haemorrhage Watery or serous Mucopurulent to purulent A dry eye Itching Chlamydial Acute bacterial conjunctivitis conjunctivitis Mild to Moderate none to severe

Viral Allergic conjunctivitis conjunctivitis

Figure 1: Algorithm to use when diagnosing the cause of a red eye2

Vernal keratoconjunctivitis filter or Wood lamp is confirmatory. A branching pattern of staining suggests HSV infection or a healing abrasion. HSV Vernal keratoconjunctivitis is a bilateral, recurrent disorder infection with corneal involvement warrants ophthalmological that is common in the drier parts of South Africa. Children referral within 1-2 days. It is good practice to check for a retained and teenagers are mostly affected and the condition worsens foreign body under the upper eyelid in patients with corneal seasonally. There is often associated atopy, with a history of abrasion. Treatment includes supportive care, cycloplegic asthma and eczema in infancy. Itching associated with tears, and pain control. Referral to an ophthalmologist is photophobia and the sensation of a foreign body in the eye are indicated if the symptoms worsen or do not resolve within 48 characteristic symptoms. Secondary skin changes to the eyelids hours.2 occur as a consequence of persistent eye rubbing.4 Keratitis The differential diagnosis for a red eye caused by conjunctivitis is Keratitis may be infective or non-infective in origin.4 summarised in Table I. An algorithm to differentiate between an allergic or infectious cause of red eye is shown in Figure 1.2 Infective keratitis is often unilateral and may be bacterial, viral or fungal. The symptoms of a red eye may be accompanied by pain, Other infectious or non-infectious causes of a red eye photophobia, decreased vision and discharge. Corneal abrasion Bacterial keratitis is uncommon in a normal eye as the corneal Corneal abrasion is diagnosed based on the clinical presentation epithelium provides a barrier against many organisms. Most and eye examination. Fluorescein staining under a cobalt blue central corneal ulcers follow a breach in this layer, secondary to www.tandfonline.com/oemd 25 The page number in the footer is not for bibliographic referencing 26 S Afr Fam Pract 2017;59(1):22-26

Table II: Differentiatiion between an allergy or an infection based on the presenting symptoms7 Presentation Exclude Diagnosis Pathology Treatment • Three-day history of red Viral: Acute bacterial • Unilateral swollen eyelids Resolution expedited left eye • Unilateral conjunctivitis • Diffuse conjunctival by topical antibiotics • Unchanged vision • Discharge not watery redness (chloramphenicol or • Mucopurulent discharge • Lymph nodes absent • Absence of preauricular tobramycin) causing eyelids to stick lymph nodes together upon waking Allergic: • Unilateral • Discharge not mucoid • Itchiness not a complaint • Recurrent attacks of Bacterial: Acute allergic conjunctivitis Bilateral conjunctivitis, with Cold compress, redness and itchiness of • Bilateral transient swelling of the Ophthalmic antihistamines, both eyes • Discharge not eyelids and conjunctiva mast cell stabilisers • Swelling of the eyelids mucopurulent or topical glucocorticoids⁸ • Sneezing • Mucoid discharge from Viral: nose and eyes also • Discharge not watery present • No follicular reaction • Swollen lymph nodes absent • Redness and discomfort Bacterial: Bilateral viral conjunctivitis Bilateral follicular Supportive: in the left eye, which • Discharge not reaction and preauricular • Cold compress spreads to the right eye mucopurulent lymphadenopathy • Artificial tears after two days • Presence of swollen • Visual acuity unaffected lymph nodes • Watery discharge from both eyes Allergic: • Tender swelling in front • Itching is not the main of both eyes complaint • Conjunctiva not swollen either trauma or a pre-existing ocular surface disease. Other risk Conclusion factors include a history of wearing contact lenses and systemic immunosuppression. Signs include an epithelial defect which A red eye is a common complaint in general practice, with stains with fluorescein, stromal infiltrates and pus in the anterior conjunctivitis being the most common diagnosis. Although chamber. Discontinuation of wearing contact lenses and the conjunctivitis is usually a benign and self-limiting condition, it use of a plastic eye shield may be initial interventions. Since is important to make the differentiation between an allergic or bacterial keratitis has the potential to progress rapidly to corneal infectious cause in order to treat appropriately. A relevant history perforation, strict specialist referral is advised.4 should be obtained and a thorough examination conducted to

Herpes simplex keratitis typically presents with signs that include assist in the diagnosis. In addition, this assessment is necessary to decreased visual acuity, a watery discharge and epithelial lesions, identify any warning signs of serious causes that warrant referral called dendritic ulcers. Topical acyclovir, applied five times daily, in order to expedite treatment and prevent significant morbidity. is generally used. Topical steroids should be avoided in these References patients as corneal perforation may ensue.4 1. Graham RH. Red eye. Medscape Reference. Available from www.emedicine. is a significant cause of blindness, and presents medscape.com/article/1192122-overview Accessed 15 January 2015 as a red, painful eye associated with a decrease in visual acuity. 2. Cronau H, Kankanala R, Mauger T. Diagnosis and Management of Red Eye in Fungal ulcers are less aggressive than bacterial ulcers, and are Primary Care. American Family Physician. 2010; 81:2 slow spreading and dull grey in appearance, with feather-like 3. Jacobs DS. Evaluation of the red eye. www.uptodate.com Topic 6900, version 19.0. Accessed 15 January 2015 extensions. Immediate referral of these patients is necessary.4 4. Mohamed N, Smit DP. Basic for the health practitioner: the red Application in practice: is it an allergy or an infection? eye. South African Pharmaceutical Journal. 2013; 80(7):20-26 5. Du Toit N, Van Zyl L. The red eye. South African Family Practice. 2013;55:1 Table II provides practical examples of patient presentations 6. South African Medicines Formulary.11th Edition that require treatment for a red eye. Based on the presenting 7. Smit D. A challenging red eye clinical quiz. South African Family Practice. 2014. symptoms and an assessment of which aetiology should be Vol 56 No. 2 excluded, it is possible to differentiate between an allergy or 8. Hamrah P. Dana R. Allergic conjunctivitis: Management. www.uptodate.com infection.7 Topic 90512 Version 10.0 Accessed 24 February 2017

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