Sore throat – infectious and non infectious causes, red flag symptoms and signs, risk stratification, investigations, empirical management

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sore throat pharyngitis management

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Sore Throat: A Clinical Reference

1. Causes

Infectious Causes

Viral (majority of cases — ~70–80% of adults, higher in children)

Pathogen	Syndrome	Estimated % of pharyngitis
Rhinovirus (100+ types)	Common cold	15–20%
Coronavirus (3+ types)	Common cold	>5%
Adenovirus (types 3, 4, 7, 14, 21)	Pharyngoconjunctival fever	~6%
Herpes simplex virus 1 & 2	Gingivitis, stomatitis, pharyngitis	~4%
Parainfluenza virus (1–4)	Common cold, croup	~2%
Influenza A & B	Influenza	~2%
RSV	Bronchiolitis, pharyngitis	1–2%
Coxsackievirus A (herpangina)	Vesicular pharyngitis	<1%
Epstein-Barr virus	Infectious mononucleosis	<1% (1–6% in young adults)
Cytomegalovirus	Mono-like syndrome	<1%
HIV-1	Acute retroviral syndrome	<1%
SARS-CoV-2	COVID-19	Variable

Bacterial

Pathogen	Syndrome	Estimated %
Streptococcus pyogenes (GABHS)	Pharyngitis, tonsillitis, scarlet fever	10–23%
Fusobacterium necrophorum	Pharyngitis, Lemierre's syndrome	5–10%
Group C/G streptococci	Pharyngitis	3–6%
Neisseria gonorrhoeae	Pharyngitis	<1%
Corynebacterium diphtheriae	Diphtheria (pseudomembrane)	<1%
Arcanobacterium haemolyticum	Pharyngitis ± rash	<1%
Mycoplasma pneumoniae	Atypical pharyngitis with bronchopulmonary sx	<1%
Chlamydia pneumoniae	Atypical pharyngitis	<1%
Anaerobes (Bacteroides, Fusobacterium)	Peritonsillar/deep space infection	Polymicrobial
Treponema pallidum	Secondary syphilis	<1%

Fungal

Candida spp. — cottage-cheese-like plaques that scrape off and bleed; seen in immunosuppressed patients, neonates, inhaled corticosteroid users.

Non-Infectious Causes

Category	Examples
Gastro-oesophageal reflux	Laryngopharyngeal reflux — chronic hoarseness, globus, morning symptoms, no fever
Allergic/irritant	Post-nasal drip (allergic rhinitis), dry air, smoke, chemical inhalation
Neoplastic	Head and neck malignancy (tongue base, larynx, thyroid, lymphoma/leukaemia) — persistent unilateral sore throat, weight loss, dysphagia
Autoimmune/inflammatory	Thyroiditis (de Quervain's), Sjögren's syndrome
Referred pain	Acute coronary syndrome, pericarditis, myocarditis presenting as throat pain
Trauma	Foreign body (fishbone, bone fragment), caustic ingestion, intubation, neck haematoma
Drug-induced	Chemotherapy-induced mucositis, ACE-inhibitor-related angioedema
Kawasaki disease	Children — fever ≥5 days, strawberry tongue, rash, cervical lymphadenopathy
Stevens-Johnson syndrome	Mucositis + skin blistering — drug reaction

Harrison's (2025) explicitly states: "Sore throat is not synonymous with pharyngitis and can also be caused by submandibular space, retropharyngeal and peritonsillar abscesses, thyroiditis, gastroesophageal reflux, tumors, and postnasal drainage."

2. Red Flag Symptoms and Signs

These indicate critical or emergent pathology requiring immediate assessment and possible airway management:

🚨 Critical (Airway-Threatening)

Stridor at rest — epiglottitis, retropharyngeal abscess, angioedema, croup
Drooling / inability to swallow secretions — epiglottitis ("tripod position")
Trismus — deep space infection (peritonsillar/parapharyngeal abscess, Ludwig's angina)
Muffled "hot potato" voice — supraglottic obstruction, peritonsillar abscess
Neck stiffness + swelling — Ludwig's angina, parapharyngeal/retropharyngeal abscess, expanding haematoma
Respiratory distress — any cause of upper airway compromise
Uvular deviation — peritonsillar abscess (uvula deviated away from affected side)
Rigors / severe systemic toxicity — bacteraemia, Lemierre's syndrome, sepsis

⚠️ Emergent (Requires Urgent Investigation)

Unilateral persistent sore throat not responding to penicillin — consider N. gonorrhoeae, malignancy, Lemierre's
Visible neck mass — abscess, lymphoma, thyroid malignancy, leukaemia infiltration
Persistent symptoms >5 days without improvement
Odynophagia severe enough to prevent oral intake → dehydration
Pseudomembrane on tonsillar/pharyngeal surface — diphtheria
Referred jaw or ear pain with palpable neck mass
Symptoms in immunocompromised host
Suspected foreign body ingestion

Features Favouring Serious Bacterial/Suppurative Complications

Marked unilateral tonsillar swelling with fluctuance → peritonsillar abscess
Bulging posterior pharyngeal wall → retropharyngeal abscess
Submandibular/sublingual floor-of-mouth induration → Ludwig's angina
Septic jugular vein thrombophlebitis (neck pain + fever + pulmonary emboli) → Lemierre's syndrome

3. Risk Stratification — The Modified Centor (McIsaac) Score

This stratifies the probability of Group A Streptococcal (GAS) pharyngitis:

Criterion	Points
History of fever (>38°C)	+1
Tonsillar exudates or swelling	+1
Tender anterior cervical lymphadenopathy	+1
Absence of cough	+1
Age 3–14 years	+1
Age 15–44 years	0
Age ≥45 years	−1

Probability of GABHS by score:

Score	GABHS probability	Recommended action
0 or −1	2–7%	No test, no antibiotics
1	3–13%	No test, no antibiotics
2	8–22%	Perform rapid antigen test (RADT)
3	19–38%	Perform RADT
4–5	41–>50%	Empirical antibiotics OR RADT

Rosen's EM notes: "the prevalence of GAS is greater than 50% in patients with a score of 4 or higher."

Features that increase viral likelihood (reducing Centor score relevance):

Rhinorrhoea, sneezing, cough, hoarseness, conjunctivitis — all suggest viral aetiology.

Features suggesting infectious mononucleosis (EBV) over GAS:

Posterior cervical or posterior auricular lymphadenopathy
Splenomegaly
Palate petechiae + gelatinous uvula
Age 15–30 years

4. Investigations

Bedside

Test	Purpose
Rapid Antigen Detection Test (RADT) / Optical Immunoassay	First-line GAS test; sensitivity ~60–80%, specificity ~90–97%
Throat swab for culture (5% sheep blood agar)	Gold standard for GAS (sensitivity 96%); results in 24–48h; use if RADT negative with high clinical suspicion (especially children)
Monospot (heterophile antibody test)	Screening for EBV/infectious mononucleosis (may be falsely negative in first week)
NAAT (nucleic acid amplification test)	Higher sensitivity than RADT for GAS; also available for gonorrhoea, Chlamydia

Blood Tests (for complex or severe presentations)

Test	Indication
FBC	Lymphocytosis with atypical lymphocytes (>10%) — EBV mononucleosis; WCC for severity of infection
EBV serology (VCA IgM/IgG, EA, EBNA)	Confirm EBV if monospot negative but clinical suspicion high
HIV antigen/antibody (4th-gen)	Acute retroviral syndrome if exposure history + systemic symptoms
ASO titre	Retrospective evidence of prior GAS — not useful acutely
CRP / ESR	Systemic inflammation; useful in suspected complications
Blood cultures	Suspected bacteraemia, Lemierre's, severe sepsis
Gonococcal NAAT or culture (pharyngeal swab)	If sexually active, MSM, risk factors
TFTs + thyroid ultrasound	If thyroiditis suspected

Imaging (reserved for suspected complications)

Study	Indication
Lateral soft tissue neck X-ray	Quick assessment — retropharyngeal widening at C2 (>7 mm in adults); epiglottis "thumb sign"
Contrast CT neck	Test of choice for peritonsillar abscess, retropharyngeal/parapharyngeal abscess; ring-enhancing fluid collection confirms abscess vs cellulitis
Transcervical/intraoral ultrasound	Diagnosis and aspiration guidance for peritonsillar abscess
CT chest	Lemierre's syndrome — septic pulmonary emboli

⚠️ A patient with airway distress should not be sent unobserved for CT scanning. — Tintinalli's

5. Empirical Management

Step 1: Assess for Airway Compromise First

Signs of stridor, drooling, trismus, respiratory distress → emergent airway preparation + ENT consultation
Secure airway before disease-specific treatment

Step 2: Symptomatic Treatment (ALL patients)

Analgesia: Paracetamol or NSAIDs (ibuprofen) — first-line for pain in all pharyngitis
Saline gargles, humidification, soft foods, warm fluids with honey
Ensure adequate oral hydration; IV fluids if unable to take orally
Corticosteroids (adjunct): Single dose of dexamethasone 0.6 mg/kg (max 10 mg) PO/IM — for patients ≥5 years with significant swelling or dysphagia. Reduces pain duration. (Note: Harrison's 2025 cautions that even short steroid courses carry small risks of sepsis, GI bleeding, VTE; routine use is not universally recommended.)

Step 3: Antibiotic Decision by Clinical Scenario

Viral Pharyngitis (majority of cases)

No antibiotics
Educate patient: antibiotics confer no benefit for viral pharyngitis, worsen antibiotic resistance, and carry adverse effects
Reassure: resolves in 3–7 days

GAS Pharyngitis (RADT positive, or high Centor score 4–5)

Antibiotic	Regimen
Penicillin V (1st choice)	500 mg PO QID or 1000 mg PO BD × 10 days
Amoxicillin (preferred in children)	500 mg PO BD or 1000 mg PO OD × 10 days
Benzathine penicillin G (IM, single dose)	1.2 million units IM — good for adherence concerns
Penicillin allergy (non-anaphylactic): Cephalexin	500 mg PO BD × 10 days
Penicillin allergy (non-anaphylactic): Cefadroxil	1g PO OD × 10 days
Severe penicillin allergy: Clindamycin	300 mg PO TDS × 10 days
Severe penicillin allergy: Clarithromycin / Erythromycin	Standard dosing × 10 days

GAS has never developed resistance to penicillin. 10-day courses are more effective than shorter ones.

Infectious Mononucleosis (EBV)

No antibiotics (unless secondary bacterial infection)
Avoid amoxicillin/ampicillin — causes florid maculopapular rash in ~90% of EBV patients
Rest, analgesia; avoid contact sports (splenomegaly → rupture risk)
Steroids for severe airway obstruction or thrombocytopenia

Peritonsillar Abscess

Drainage (needle aspiration or incision) is the definitive treatment
Antibiotics (post-drainage): penicillin VK or amoxicillin-clavulanate; cover GAS and anaerobes
If not fluctuant (peritonsillar cellulitis): antibiotics as per GAS protocol
Severe systemic illness: IV clindamycin 900 mg TDS + ceftriaxone 1 g IV OD

Retropharyngeal / Parapharyngeal Abscess

Immediate ENT consultation; most require surgical drainage
Empirical IV antibiotics: piperacillin-tazobactam 3.375 g IV, or ampicillin-sulbactam 3 g IV, or clindamycin 900 mg IV + metronidazole 1 g IV
Add vancomycin in high-risk patients (MRSA coverage)

Epiglottitis

Secure airway first; keep patient calm in comfortable position
ENT + anaesthesia immediately
Empirical IV antibiotics: ceftriaxone 50 mg/kg (or 1–2 g) IV OD (covers Streptococcus, Staphylococcus, non-typeable H. influenzae)

Ludwig's Angina

Airway control is priority (awake fibreoptic intubation preferred)
Broad-spectrum IV antibiotics: penicillin/β-lactam + metronidazole, or piperacillin-tazobactam
Surgical drainage

Lemierre's Syndrome (Fusobacterium necrophorum)

Prolonged sore throat + septic emboli + internal jugular vein thrombophlebitis
IV antibiotics: metronidazole + β-lactam (e.g. ampicillin-sulbactam or piperacillin-tazobactam)
Anticoagulation is controversial; ENT/ID consultation

Gonococcal Pharyngitis

Ceftriaxone 500 mg IM single dose (or 1 g if weight >150 kg)
Treat for concomitant chlamydia if not excluded

Diphtheria

Diphtheria antitoxin (neutralises free exotoxin) — give empirically, do not wait for culture
Benzylpenicillin IV or erythromycin; strict isolation

When to Refer / Admit

Indication	Action
Any airway compromise or stridor	Emergency — immediate airway management + ENT
Suspected deep space infection (peritonsillar, retropharyngeal, parapharyngeal, Ludwig's)	Admit for IV antibiotics + surgical consultation
Lemierre's syndrome	Admit for IV antibiotics ± anticoagulation
Unable to maintain oral hydration	Admit for IV fluids
Persistent symptoms >5 days without improvement	Reassess, consider complications
Suspected malignancy	Urgent ENT/head-and-neck surgery referral
Suspected acute HIV	HIV testing, ID referral
Immunocompromised host with pharyngitis	Lower threshold for admission

Sources: Harrison's Principles of Internal Medicine 22E (2025), Rosen's Emergency Medicine 9E, Tintinalli's Emergency Medicine, Textbook of Family Medicine 9E.

Recent guideline note: A 2024 Italian intersociety consensus on acute pharyngitis in children (PMID: 39501298) reinforces that GAS-directed antibiotic treatment should be guided by testing (RADT or culture) rather than clinical features alone, consistent with the Centor/McIsaac framework above.

FevrPAIN score

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FeverPAIN score sore throat criteria management NICE guidelines

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FeverPAIN Score

The FeverPAIN score is a clinical prediction rule developed in the UK (Little et al., 2013 — the DESCARTE trial) specifically to guide antibiotic prescribing decisions in primary care for acute sore throat. It is endorsed by NICE (guideline NG84, Sore throat — acute) as one of two recommended scoring tools (alongside Centor/McIsaac).

Criteria — One Point Each

Letter	Criterion	Detail
Fe	Fever in the last 24 hours	Temperature recorded or reported ≥38°C
v	Severe symptoms (attendance within 3 days)	Presenting within 3 days of onset of symptoms
r	Purulence	Purulent tonsils/exudate on examination
P	Severe / Patchy tonsil involvement	Inflamed tonsils with severe or patchy exudate
A	Attended rapidly — severe symptoms	— (already captured above)
N	No cough or coryza	Absence of cough and coryza

More precisely, the five scored items are:

#	Criterion	Points
1	Fever ≥38°C in the last 24 hours	1
2	Exclusion of severe infection not needed — attendance within 3 days of onset	1
3	v — Severe sore throat (or rapidly worsening)	1
4	Purulence (pus on tonsils)	1
5	Absence of cough or coryza (No cough)	1

Total: 0–5 points

Interpretation and Management

Score	Likelihood of streptococcal infection	Recommended Action
0–1	13–18% (low)	No antibiotic — reassurance, symptomatic treatment only
2–3	34–40% (moderate)	Delayed antibiotic prescription — issue prescription to use only if not improving after 3–5 days
4–5	62–65% (high)	Immediate antibiotic prescription

Antibiotic Choice (when indicated, per NICE NG84)

First line: Phenoxymethylpenicillin (Penicillin V) 500 mg QDS or 1000 mg BD × 5–10 days
Penicillin allergy: Clarithromycin 250–500 mg BD × 5 days, or erythromycin

FeverPAIN vs. Centor/McIsaac — Key Differences

Feature	FeverPAIN	Centor / McIsaac
Origin	UK (DESCARTE trial, 2013)	USA (Centor 1981; McIsaac modification 1998)
Endorsed by	NICE (UK primary care)	IDSA, multiple international guidelines
Age adjustment	No	Yes (McIsaac adds ±1 for age)
Rapid attendance criterion	Yes ("within 3 days")	No
Severity criterion	Yes	No
Score range	0–5	−1 to +5
Validated population	UK primary care (adults + children ≥5y)	Mixed (primary care + ED)
Performance	AUC ~0.59–0.66	AUC ~0.62–0.73

Evidence and Limitations

A 2021 secondary analysis of the TOAST RCT (Seeley et al., BJGP Open, PMID: 34551959) evaluated both tools in UK adults not requiring immediate antibiotics:

Overall diagnostic accuracy was poor for both tools: AUC 0.59 for FeverPAIN vs. 0.62 for Centor (neither significantly better than the other)
FeverPAIN ≥4 gave a post-test probability of streptococcal infection of only 27.3%
Negative predictive value was reasonable: 84.1% for FeverPAIN score ≥4 threshold
Despite poor discrimination, higher scores were associated with increased delayed antibiotic prescribing — suggesting the tools influence clinical behaviour more than microbiological diagnosis

Key implication: Neither FeverPAIN nor Centor reliably distinguishes bacterial from viral sore throat. Their primary utility is as antibiotic stewardship frameworks — reducing unnecessary immediate prescriptions while providing a structured rationale for delayed or immediate prescribing in a minority of patients.

Clinical Bottom Line

Use FeverPAIN in UK primary care / GP settings where NICE guidance applies
Use Centor/McIsaac in emergency department or international settings where it is better validated and more widely used
Neither tool should replace clinical judgement, particularly for red flag presentations (stridor, drooling, trismus, unilateral peritonsillar swelling)
RADT (rapid antigen test) combined with a clinical score improves accuracy and is now recommended in several guidelines as the preferred approach

Keratoconjunctivitis- causes, er approach

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Keratoconjunctivitis — Causes & Emergency Approach

Keratoconjunctivitis refers to combined inflammation of the cornea (keratitis) and conjunctiva (conjunctivitis). As Tintinalli's defines it: "Keratoconjunctivitis is the term used to indicate corneal involvement, usually in the form of punctate ulcerations." It ranges from a mild self-limiting viral illness to a vision-threatening emergency.

1. Classification of Causes

A. Infectious

Viral (most common)

Type	Causative Agent	Key Features
Epidemic Keratoconjunctivitis (EKC)	Adenovirus serovars 8, 19, 37	Most severe adenoviral form; keratitis in ~80%; highly contagious; subepithelial infiltrates persist months–years
Pharyngoconjunctival Fever (PCF)	Adenovirus serovars 3, 4, 7	Prominent sore throat; keratitis in ~30% (less severe); spread by droplets
Non-specific Follicular Adenoviral Conjunctivitis	Various adenovirus serotypes	Mildest form; bilateral; no systemic illness
HSV Keratoconjunctivitis	Herpes simplex virus 1 (primary or recurrent)	Unilateral; dendritic epithelial ulcer on fluorescein; skin vesicles; anterior uveitis common; vision-threatening
Herpes Zoster Ophthalmicus (HZO)	Varicella-zoster virus	Dermatomal forehead rash (V1); Hutchinson's sign (nasal tip vesicles) predicts ocular involvement; keratoconjunctivitis, uveitis, scleritis
Acute Haemorrhagic Conjunctivitis	Enterovirus 70, Coxsackievirus A24	Tropical; rapid onset; prominent subconjunctival haemorrhages; resolves 1–2 weeks
Molluscum Contagiosum	Poxvirus	Umbilicated eyelid/eyelash margin nodules causing chronic follicular conjunctivitis via viral shedding; look for lid lesions!
Microsporidial	Encephalitozoon, Nosema spp.	Diffuse coarse punctate keratitis; chronic; immunocompromised patients (HIV)
Vaccinia / Measles / Varicella	Respective viruses	Conjunctivitis as part of systemic illness
COVID-19	SARS-CoV-2	Conjunctival hyperaemia, chemosis, epiphora; viral RNA in tears

Bacterial

Cause	Features
Staphylococcus, Streptococcus	Common bacterial keratoconjunctivitis; mucopurulent discharge; corneal ulceration risk
Chlamydia trachomatis (Trachoma — serovars A–C)	Leading infectious cause of blindness worldwide; follicular conjunctivitis → pannus (superior corneal vascularisation) → trichiasis → corneal scarring
Neisseria gonorrhoeae	Hyperacute purulent conjunctivitis; corneal perforation risk within hours; treat as emergency
Pseudomonas aeruginosa	Contact lens wearers; aggressive corneal ulceration
Moraxella, Haemophilus	Less common

Chlamydial

Adult inclusion conjunctivitis (serovars D–K): chronic follicular conjunctivitis, superior pannus, punctate keratitis
Trachoma (serovars A–C): public health emergency — WHO elimination target 2030

Fungal

Candida, Fusarium, Aspergillus — rare; usually following trauma or immunosuppression; keratoconjunctivitis with satellite infiltrates

Parasitic

Acanthamoeba: contact lens users; severe pain disproportionate to signs; ring infiltrate; misdiagnosed as HSV early
Microsporidia: immunocompromised (HIV); coarse punctate keratitis

B. Allergic / Immunological

Type	Key Features	Corneal Involvement
Vernal Keratoconjunctivitis (VKC)	Boys 5–15 years; warm dry climates; IgE + cell-mediated; giant cobblestone papillae (upper tarsal); Horner-Trantas dots (limbal); intense itching; seasonal	Shield ulcers, epithelial macroerosions, plaques; Bowman layer exposed; keratoconus risk
Atopic Keratoconjunctivitis (AKC)	Adults 30–50; perennial; severe atopic dermatitis; bilateral inferior tarsal papillae; Hertoghe sign, Dennie-Morgan folds; chronic + unremitting	Inferior punctate erosions; peripheral vascularisation + stromal scarring; persistent epithelial defects; perforation risk
Giant Papillary Conjunctivitis (GPC)	Contact lens users, sutures, prostheses; upper tarsal giant papillae	Punctate keratitis; contact lens intolerance
Seasonal / Perennial Allergic Conjunctivitis	Common; watery discharge; itching; no corneal involvement typically	Minimal

C. Non-Infectious / Other

Cause	Notes
Keratoconjunctivitis Sicca (Dry Eye)	Tear deficiency (aqueous deficient: Sjögren's, post-radiotherapy; or evaporative: meibomian gland dysfunction); burning, foreign body sensation, photophobia; punctate epithelial erosions on fluorescein
Toxic / Medicamentosa	Preservatives (benzalkonium chloride), aminoglycosides, antivirals, IOP-lowering drops; inferior papillary reaction + SPK
Chemical / Irritant	Acid/alkali burns; UV keratoconjunctivitis ("welder's flash", snow blindness)
Stevens-Johnson Syndrome / TEN	Drug reaction; severe conjunctival mucositis → symblepharon → corneal scarring; emergency
Autoimmune	Sjögren's syndrome, rheumatoid arthritis, ocular cicatricial pemphigoid, GvHD
Rosacea	Chronic blepharitis → SPK, corneal vascularisation, recurrent chalazia
Neurotrophic keratitis	Loss of corneal sensation (post-herpetic, V nerve damage) → exposure keratopathy
UV/Radiation	Photokeratitis — intense photophobia, tearing, foreign body sensation ~6–12h after exposure

2. Emergency Department Approach

Step 1 — Triage: Rule Out Vision-Threatening Emergencies Immediately

🚨 Emergency	Features
Alkali/acid chemical burn	History of splash; high pH → liquefactive necrosis; limbal blanching
Gonococcal conjunctivitis	Hyperacute purulent discharge; lid oedema; corneal melt risk
HSV dendrite / keratitis	Branching dendritic staining; do not miss with steroids
Acute angle-closure glaucoma	Hazy cornea, fixed mid-dilated pupil, nausea/vomiting — mimic
Stevens-Johnson syndrome	Mucositis + skin desquamation; bilateral
Corneal perforation / endophthalmitis	Post-trauma or post-op; Seidel sign; hyphaema
Orbital cellulitis	Proptosis, limited motility, fever

⚠️ If alkali/acid burn: irrigate immediately with 1–2 L normal saline before any other assessment. Check pH. Target pH 7.0–7.4.

Step 2 — History

Onset and laterality (unilateral vs. bilateral, which eye first)
Discharge character: watery (viral/allergic), mucopurulent (bacterial), stringy mucoid (VKC), purulent/copious (gonococcal)
Symptoms: itching (allergic), pain (keratitis, uveitis, chemical), photophobia, blurred vision
Contact history: URI, sick contacts, recent conjunctivitis cluster (epidemic)
Contact lens use: Pseudomonas, Acanthamoeba risk
STI risk: gonorrhoea, chlamydia
Systemic disease: atopy, autoimmune, HIV
Drug history: preservative-containing drops, sulfonamides, penicillins (SJS)
Occupation / exposure: welding/UV, chemical splash

Step 3 — Examination

Visual acuity — document baseline; reduced VA indicates corneal/macular involvement
External exam: lid oedema, vesicles (HSV/HZO), umbilicated nodules (molluscum), eczematoid skin (AKC), Hutchinson's sign
Discharge type and amount
Preauricular lymphadenopathy — strongly suggests viral (adenovirus, EBV, HSV)
Conjunctiva: injection pattern (diffuse vs. ciliary flush), follicles vs. papillae, membranes/pseudomembranes, haemorrhages, chemosis
- Follicles (smooth, avascular bumps) → viral, chlamydial, toxic
- Papillae (vascular centre) → bacterial, allergic
- Giant papillae → VKC, GPC
- Cobblestone appearance → VKC (upper tarsus)
- Horner-Trantas dots → VKC/AKC (limbal white deposits = eosinophil aggregates)
Slit lamp (if available):
- Corneal staining with fluorescein under cobalt blue light — essential
- Dendrite → HSV
- Punctate epithelial keratitis (SPK) → adenoviral EKC, dry eye, toxic, chlamydial
- Subepithelial infiltrates → EKC (late, immune-mediated, persist for months)
- Shield ulcer → VKC
- Ring infiltrate → Acanthamoeba
- Anterior chamber: cells/flare → uveitis (HSV, HZO, uveitis-associated)
IOP measurement if indicated (hazy cornea, post-viral)

Step 4 — Investigations

Test	Indication
Fluorescein staining	All patients — corneal epithelial integrity, dendrite pattern
Conjunctival swab C&S	Suspected bacterial keratoconjunctivitis, neonates, contact lens users, non-responding cases
PCR (viral)	Adenovirus, HSV, VZV — point-of-care adenoviral immunochromatography (10 min, excellent sensitivity/specificity) available
Giemsa stain (scrapings)	Mononuclear cells = adenoviral; multinucleate giant cells = herpetic; intracytoplasmic inclusions = chlamydial
Chlamydia NAAT	Chronic follicular conjunctivitis, adult inclusion conjunctivitis suspicion
GC NAAT / culture	Hyperacute purulent discharge, sexual history
pH strip	Chemical injury — test before and after irrigation
HIV test	Microsporidial infection, bilateral molluscum, recurrent/atypical presentation
Acanthamoeba smear/culture	Contact lens users with severe pain, ring infiltrate

Step 5 — Management by Aetiology

Adenoviral / EKC

Supportive: cool compresses, preservative-free artificial tears 4–6x/day, ocular decongestant (e.g. Naphcon-A 1 drop TDS PRN)
Avoid contact lenses until fully resolved
No antiviral — no clinically useful agent against adenovirus
Topical steroids (prednisolone 0.5% QDS) only for severe membranous/pseudomembranous disease or symptomatic subepithelial infiltrates — use with caution (masks symptoms, extends viral shedding, can raise IOP); always exclude HSV first
Infection control: rigorous hand hygiene, separate towels, disinfect instruments and surfaces (sodium hypochlorite / povidone-iodine); exclude from work/school; highly contagious
Self-limiting within 2–3 weeks, but subepithelial infiltrates may persist months

HSV Keratoconjunctivitis

Topical antiviral: trifluridine 1% drops 1 drop q2h (max 9 drops/24h) while awake until re-epithelialisation, then q4h for 7 days (max 21 days total)
Alternative: ganciclovir 0.15% gel 5x/day until re-epithelialisation, then TDS × 7 days
Oral aciclovir 400 mg 5x/day or valaciclovir for significant disease, immunocompromised
DO NOT USE topical steroids on dendritic keratitis alone — risks progression to geographic/disciform keratitis
Cycloplegic (homatropine 2%) for associated uveitis/ciliary spasm
Urgent ophthalmology referral — vision-threatening

Herpes Zoster Ophthalmicus

Oral valaciclovir 1 g TDS × 7–10 days (or aciclovir 800 mg 5x/day); start within 72h of rash onset
Topical artificial tears for keratitis
Topical steroid (under ophthalmology guidance) for stromal keratitis or uveitis
Ophthalmology referral for all patients with V1 zoster + any ocular sign

Bacterial Keratoconjunctivitis

Trimethoprim/polymyxin B (Polytrim) drops — first-line for non-contact-lens users; covers Staph and Strep
Fluoroquinolone drops (ciprofloxacin, moxifloxacin, levofloxacin) — contact lens wearers (Pseudomonas cover); also corneal ulcer first-line
Avoid contact lenses; culture if severe, non-responding, or ulcer present
Follow up with ophthalmology for any corneal ulcer

Gonococcal Conjunctivitis (Hyperacute — EMERGENCY)

Ceftriaxone 1 g IM single dose (or IV if severe corneal involvement)
Copious saline irrigation of conjunctiva
Treat concomitant chlamydia: azithromycin 1 g PO single dose or doxycycline 100 mg BD × 7 days
Urgent ophthalmology: risk of corneal melt within hours
Admit if corneal involvement

Allergic (VKC / AKC) — Acute Flare

Topical antihistamine / mast cell stabiliser combination (e.g. olopatadine, ketotifen, azelastine) — first-line
Cold compresses, avoid allergen triggers, sunglasses
Topical NSAID (ketorolac) for itching
Cyclosporine 0.05–1% topical — steroid-sparing; established benefit in VKC/AKC
Short-course topical steroid (loteprednol, fluorometholone) — for acute flares only; ophthalmology supervision needed; monitor IOP
Shield ulcer: surgical debridement + antibiotic cover to prevent secondary infection; urgent ophthalmology
Oral antihistamine, nasal steroid for concurrent rhinitis
Avoid topical steroids unsupervised — risk of cataract and glaucoma

Keratoconjunctivitis Sicca (Dry Eye Emergencies — Epithelial Breakdown)

Preservative-free artificial tears frequently (q1–2h); carmellose, hypromellose, sodium hyaluronate
Lubricating ointment at night (Lacrilube, Vitapos)
Remove/treat underlying cause (stop offending drops, treat blepharitis)
Punctal plugs — increases ocular surface moisture
Topical cyclosporine (Restasis/Ikervis) for inflammatory dry eye
Ophthalmology for persistent epithelial defects; bandage contact lens consideration

Chemical / UV Keratoconjunctivitis

Immediate copious irrigation for chemical burns (1–2 L NS or water); check pH, target 7.0–7.4; continue irrigation until pH normalised
Alkali burns (lime, bleach, cement) penetrate deeper — worse prognosis
Topical anaesthetic (proxymetacaine) for examination only — do not prescribe for repeated use
Topical antibiotic + lubricants; cycloplegic for pain
Urgent ophthalmology for grade 2+ burns

Stevens-Johnson Syndrome

Admit: this is a systemic emergency
Ophthalmology at bedside: lubricants, steroid drops, symblepharon ring or rod to prevent fornix obliteration
Withdraw causative drug
Systemic IVIG or ciclosporin in some cases (specialist decision)

Step 6 — Discharge vs. Refer

Disposition	Criteria
Discharge with follow-up	Mild-moderate viral/allergic conjunctivitis; no corneal ulcer; VA preserved; not immunocompromised
Urgent ophthalmology (same day / next day)	Any corneal staining/ulcer; HSV dendrite; HZO; moderate-severe keratitis; contact lens-related corneal ulcer; VKC shield ulcer
Emergency ophthalmology (immediate)	Gonococcal conjunctivitis; chemical burn (after irrigation); suspected corneal perforation; endophthalmitis; acute angle-closure (excluded but referred)
Admit	Chemical burns (grade ≥2); SJS/TEN; systemic sepsis with eye involvement; severe corneal melt

Key Pitfalls in the ED

Missing HSV — always stain the cornea with fluorescein; steroid drops given for "red eye" + HSV dendrite = geographic ulcer, stromal scarring, vision loss
Missing gonococcal infection — copious purulent discharge needs urgent culture and immediate treatment; cornea can perforate
Not irrigating chemical burns immediately — every second of alkali contact worsens prognosis
Diagnosing viral conjunctivitis without fluorescein — misses herpetic dendrites and punctate keratitis
Prescribing topical steroids without ophthalmology input — catastrophic if EKC coexists with early HSV or if intraocular pressure rises

Sources: Kanski's Clinical Ophthalmology 10th Ed., Tintinalli's Emergency Medicine, Rosen's Emergency Medicine 9th Ed., The Wills Eye Manual, Harriet Lane Handbook 23rd Ed., Harrison's 22nd Ed. (2025).

Approach to red eye in ER

Finding Sources

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Finding Sources

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Finding Sources

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I now have a comprehensive dataset from Tintinalli's and Rosen's. I have enough to compile a thorough, structured ER approach to red eye.

Approach to the Red Eye in the Emergency Department

Step 1 — Identify the Immediately Life/Vision-Threatening Causes First

Before anything else, triage these conditions. Missing any of them leads to permanent vision loss.

🚨 Priority	Condition	Key Clue
CRITICAL	Chemical burn (acid/alkali)	History of splash → irrigate immediately before full assessment
CRITICAL	Orbital compartment syndrome	Proptosis, ↑IOP, limited motility, pain → lateral canthotomy
CRITICAL	Open globe / penetrating injury	Teardrop pupil, loss of red reflex, visible wound, hyphaema
CRITICAL	Acute angle-closure glaucoma	Severe pain, hazy cornea, fixed mid-dilated pupil, nausea/vomiting, IOP often >50 mmHg
EMERGENT	Gonococcal conjunctivitis	Hyperacute purulent discharge → corneal melt within hours
EMERGENT	Endophthalmitis	Post-op or post-trauma, hypopyon, loss of red reflex
EMERGENT	Orbital cellulitis	Proptosis, restricted motility, fever, pain on movement
EMERGENT	Central retinal artery occlusion	Painless, sudden, profound monocular visual loss; cherry-red spot
URGENT	HSV keratitis (dendrite)	Do not miss — steroids are catastrophic
URGENT	Corneal ulcer	Stromal white infiltrate; pain; contact lens user
URGENT	Anterior uveitis/iritis	Perilimbal flush, photophobia, miosis, cells + flare on slit lamp
URGENT	Scleritis	Deep boring pain, violaceous injection, RA/GPA association

Step 2 — History

Key Questions

Domain	Ask About
Onset	Sudden vs. gradual; duration
Pain character	Severe/throbbing = glaucoma, scleritis; aching = uveitis; foreign body sensation = corneal cause, dry eye; painless = conjunctivitis, SCH
Discharge	Watery (viral/allergic) · mucopurulent (bacterial) · copious purulent (gonococcal) · stringy mucoid (VKC) · none (uveitis, glaucoma)
Photophobia	Iritis, corneal disease, meningism
Visual change	Any blur/halos/loss → urgent; halos around lights = corneal oedema (acute glaucoma); flashes/floaters = vitreous or retinal
Laterality	Bilateral often viral/allergic; unilateral favours bacterial, HSV, uveitis, glaucoma
Trauma	Chemical splash, foreign body, blunt, penetrating, welding/UV
Contact lenses	Risk for Pseudomonas ulcer, Acanthamoeba, GPC
STI history	Gonorrhoea, chlamydia
Systemic disease	Ankylosing spondylitis, RA, IBD, sarcoidosis, Reiter's (HLA-B27 diseases) = recurrent uveitis risk; rosacea
Drug history	Topical drops (toxic medicamentosa), sulfonamides/penicillins (SJS), mydriatics (precipitate angle closure)
Sick contacts / recent URI	Adenoviral EKC
Post-op / post-injection	Endophthalmitis
Immunocompromised	HIV → CMV retinitis, microsporidia, molluscum; steroids → fungal

Step 3 — Examination

A. Visual Acuity — First and Always

Document VA in each eye before any drops. Reduced VA suggests corneal, intraocular, or posterior segment pathology. Normal VA in a red eye is generally reassuring.

B. External Inspection

Finding	Significance
Lid oedema	Infection, allergy, orbital cellulitis
Vesicles on lid/skin	HSV (unilateral) or HZO (dermatomal)
Umbilicated lid nodule	Molluscum contagiosum → chronic follicular conjunctivitis
Proptosis	Orbital cellulitis, retrobulbar haematoma, thyroid eye disease
Hutchinson's sign (vesicles on nose tip)	Nasociliary branch involvement → high risk of ocular HZO
Eczematoid lid skin	Atopic keratoconjunctivitis

C. Pattern of Injection

Pattern	Meaning
Diffuse conjunctival redness	Conjunctivitis (bacterial, viral, allergic)
Ciliary/perilimbal flush (redness greatest around the cornea)	Corneal disease, anterior uveitis/iritis
Sectoral episcleral injection	Episcleritis (bright red, moveable vessels)
Deep violaceous hue	Scleritis (vessels don't blanch with phenylephrine)
Generalised with chemosis	Allergic, anaphylaxis, gonococcal
Localised with nodule	Nodular scleritis, episcleritis

Phenylephrine 10% test: Blanching → episcleritis (superficial). No blanching → scleritis (deeper vessels).

D. Discharge

Character	Cause
Watery / serous	Viral conjunctivitis, allergic
Mucopurulent	Bacterial conjunctivitis (Staph, Strep, H. influenzae)
Copious purulent / hyperacute	Gonococcal conjunctivitis — EMERGENCY
Stringy mucoid	VKC, dry eye
None	Uveitis, glaucoma, scleritis

E. Corneal Examination

White light first — look for opacity, ulcer (white infiltrate), foreign body
Fluorescein + cobalt blue light — ESSENTIAL in all red eyes:
- Dendrite (linear branching with terminal bulbs) → HSV keratitis
- Punctate epithelial staining (SPK) → dry eye, adenoviral EKC, toxic, UV keratitis
- Discrete epithelial defect → corneal abrasion, ulcer
- Seidel sign (streaming of aqueous through wound stained with fluorescein) → open globe
Corneal clarity: Hazy/oedematous → acute angle-closure glaucoma, severe keratitis
Corneal sensation (cotton wisp): Reduced → HSV, neurotrophic keratitis; test before anaesthetic drops

⚠️ Always stain the cornea — missing a dendritic ulcer and giving steroids causes geographic ulceration and permanent corneal scarring.

F. Pupils

Finding	Significance
Miotic, poorly reactive	Anterior uveitis/iritis (ciliary spasm)
Fixed mid-dilated (~5–6 mm)	Acute angle-closure glaucoma
Irregular	Posterior synechiae (uveitis), iris damage (trauma)
Afferent pupillary defect (RAPD)	Optic nerve disease, severe retinal pathology

Consensual photophobia (pain in affected eye when light shone in unaffected eye) → strongly suggests iritis.

Topical anaesthetic diagnostic test: Relief = corneal/conjunctival source. Partial relief = conjunctival. No relief = intraocular (uveitis, glaucoma).

G. Anterior Chamber (slit lamp or penlight with oblique illumination)

Finding	Significance
Hyphaema (blood layering)	Trauma, coagulopathy
Hypopyon (white cells layering)	Corneal ulcer with iritis, endophthalmitis, severe uveitis
Cells + flare (on slit lamp)	Anterior uveitis — "snowflakes in headlight beam"
Shallow anterior chamber	Risk of narrow angle; compare with other eye
Keratic precipitates (KPs)	Uveitis — "mutton fat" KPs = granulomatous (sarcoid, TB); fine KPs = non-granulomatous

H. Conjunctival Architecture (evert upper lid)

Finding	Significance
Follicles (smooth, avascular, 0.5–2mm)	Viral (inferior palpebral), chlamydial, toxic
Papillae (central vascular tuft)	Bacterial, allergic
Giant cobblestone papillae (upper lid)	Vernal keratoconjunctivitis, GPC (contact lens)
Membranes/pseudomembranes	EKC (adenoviral), SJS, β-haemolytic streptococcal
Horner-Trantas dots (limbal white dots)	VKC/AKC — eosinophil aggregates
Follicles + pannus + scarring	Trachoma

I. Preauricular Lymphadenopathy

Tender preauricular node → almost always viral (adenoviral EKC, HSV, EBV conjunctivitis).

J. Intraocular Pressure (IOP)

Normal: 10–20 mmHg
Measure in all suspected glaucoma, post-trauma, after acute red eye without obvious cause
IOP >30 mmHg warrants urgent ophthalmology
IOP may be low in iritis (ciliary body suppression of aqueous production)

K. Fundoscopy / Posterior Segment

Red reflex absent → hyphaema, cataract, vitreous haemorrhage, corneal opacification, endophthalmitis, retinoblastoma
Optic disc oedema → optic neuritis, raised ICP
Cherry-red spot → central retinal artery occlusion

Step 4 — The Differential Diagnosis: Comparison Table

(Adapted from Tintinalli's Emergency Medicine, Table 241-3)

Condition	Pain	Discharge	Photophobia	VA	Injection	Cornea	Pupil	IOP
Viral conjunctivitis	Mild / none	Watery	None–mild	Normal	Diffuse	Clear; SPK	Normal	Normal
Bacterial conjunctivitis	Mild	Mucopurulent	None	Normal	Diffuse	Clear	Normal	Normal
Allergic conjunctivitis	Itch >> pain	Watery	Mild	Normal	Diffuse ± chemosis	Clear	Normal	Normal
Corneal abrasion	Moderate–severe FB sensation	Watery	Moderate	Normal–slightly ↓	Diffuse/ciliary	Epithelial defect (fluorescein)	Normal	Normal
HSV keratitis	Mild–moderate	None/watery	Moderate	↓	Ciliary/diffuse	Dendrite	Normal or miotic	Normal or ↑
Corneal ulcer	Severe	Mucopurulent	Yes	↓	Ciliary	White infiltrate	Normal or miotic	Variable
Anterior uveitis (iritis)	Aching	None	Marked (consensual)	↓ or normal	Ciliary flush	± KPs, ± SPK	Miotic, poorly reactive	Normal or ↓
Acute angle-closure glaucoma	Severe; headache; nausea	None	Moderate	↓↓	Diffuse + ciliary	Hazy/steamy	Fixed, mid-dilated (~5 mm)	↑↑↑ (often >50)
Scleritis	Deep boring, severe	None	Mild	Normal–↓	Deep violaceous	Clear	Normal	Normal
Episcleritis	Mild	None	None	Normal	Sectoral bright red	Clear	Normal	Normal
Subconjunctival haemorrhage	None	None	None	Normal	Bright red patch	Clear	Normal	Normal
Endophthalmitis	Severe	Purulent	Yes	↓↓	Diffuse + chemosis	Hazy	Variable	Variable
Gonococcal conjunctivitis	Moderate	Copious purulent	None	Normal–↓	Marked + chemosis	Risk of melt	Normal	Normal

Step 5 — Investigations

Test	When to Use
Fluorescein stain + cobalt blue light	All patients — mandatory
IOP measurement (tonometry)	Suspected glaucoma, post-trauma, uveitis, unexplained red eye
Slit lamp examination	Cells + flare, KPs, corneal lesions, anterior chamber depth
Conjunctival swab C&S	Severe/hyperacute bacterial conjunctivitis, contact lens users, neonates, non-resolving cases
GC NAAT / culture	Hyperacute purulent discharge, sexual risk
Chlamydial NAAT	Chronic follicular conjunctivitis, inclusion conjunctivitis
PCR (adenovirus)	EKC — rapid point-of-care adenoviral immunochromatography (10 min)
Giemsa stain (scraping)	Mononuclear cells (viral), multinucleate giant cells (HSV), intracytoplasmic inclusions (chlamydial)
ESR + CRP	Suspected temporal arteritis (visual loss, jaw claudication, tender temporal artery, age >50)
FBC, coagulation	Recurrent subconjunctival haemorrhage, suspected leukaemia
POCUS (ocular ultrasound)	Retinal detachment, vitreous haemorrhage, posterior scleritis, globe rupture, retrobulbar haematoma
CT orbit (axial + coronal)	Orbital cellulitis, orbital compartment syndrome, intraocular/intraorbital foreign body, globe rupture
MRI	Optic neuritis, posterior orbital lesions (not if metallic FB)

Step 6 — Management by Diagnosis

🔴 Chemical Burn — Immediate

Irrigate before anything else — 2 L for acid (minimum 20 min); 4 L for alkali (minimum 40 min); target tear-film pH 7.0–7.4
Remove solid particles with dry swab before irrigation
Check pH with strips before and after
Alkali penetrates deeper (liquefactive necrosis) — worse prognosis
Immediate ophthalmology to ED; admit if grade ≥2

🔴 Acute Angle-Closure Glaucoma

Sequential regimen (all started simultaneously):

Step	Agent	Dose
1	Acetazolamide (carbonic anhydrase inhibitor)	500 mg IV or PO, then 250 mg PO/IV q4h (max 1 g/day)
1	Timolol 0.5% (topical β-blocker)	1 drop affected eye BD
1	Apraclonidine 1% (topical α2-agonist)	1 drop affected eye TDS
2 (if IOP not dropping after 1h)	Mannitol 20%	1.5–2 g/kg IV over 30 min

Pilocarpine no longer recommended acutely — can paradoxically shallow anterior chamber
Treat pain and vomiting (fentanyl lowers IOP; ondansetron neutral)
Definitive treatment: peripheral laser iridotomy by ophthalmology
Immediate ophthalmology consultation

🔴 Open Globe / Penetrating Injury

Rigid shield over eye (no pad), keep NPO
Analgesia + antiemetics (prevent Valsalva)
Parenteral antibiotics + tetanus prophylaxis
Ophthalmologist to ED immediately; admit for surgery

🟠 Gonococcal Conjunctivitis

Copious saline irrigation
Ceftriaxone 1 g IM (or IV if corneal involvement)
Treat concomitant chlamydia: azithromycin 1 g PO or doxycycline 100 mg BD × 7 days
Immediate ophthalmology

🟠 HSV Keratitis (Dendrite)

Topical trifluridine 1% — 1 drop q2h (max 9 drops/day) until re-epithelialisation, then q4h × 7 days
Alternative: ganciclovir 0.15% gel 5×/day
Oral aciclovir/valaciclovir for severe/immunocompromised
DO NOT give topical steroids — risk of geographic ulceration and corneal melt
Cycloplegic (homatropine 2%) if associated uveitis
Refer to ophthalmology within 24 hours

🟠 Herpes Zoster Ophthalmicus (V1 involvement)

Oral valaciclovir 1 g TDS × 7–10 days (start within 72h of rash; still give if >72h in active vesicles or immunocompromised)
Artificial tears
Ophthalmology referral for all V1 zoster with any ocular sign

🟠 Corneal Ulcer

Fluoroquinolone drops (ciprofloxacin or ofloxacin) 1 drop every hour in affected eye
Do not patch (Pseudomonas risk)
Cycloplegic (cyclopentolate 1%) for associated iritis/pain
Do not start steroids without ophthalmology guidance
Ophthalmology within 12–24 hours; culture at time of initial consultation

🟡 Anterior Uveitis (Iritis)

Cycloplegic (homatropine 2–5% or tropicamide 1%) — relieves ciliary spasm and pain, prevents posterior synechiae
Analgesia
Not an immediate emergency but requires ophthalmology review within 24–48 hours for topical corticosteroids
Investigate systemic cause if first episode or atypical

🟡 Corneal Abrasion

Topical antibiotic (erythromycin ointment or trimethoprim/polymyxin B) to prevent infection
Cycloplegic for pain relief if significant photophobia
No patching — does not speed healing
Oral analgesia (NSAIDs); topical NSAIDs (ketorolac) effective for pain
Contact lens wearers: fluoroquinolone drops (Pseudomonas cover); remove lens
Follow up in 24h if not improved

🟡 Bacterial Conjunctivitis

Trimethoprim/polymyxin B (Polytrim) — first-line, avoids sulfa/neomycin allergy; covers Staph and Strep
Contact lens wearers: topical fluoroquinolone (moxifloxacin, ciprofloxacin) — Pseudomonas cover
Usually self-limiting; antibiotics shorten course
Hygiene: hand washing, no towel sharing

🟡 Viral Conjunctivitis / EKC

Cool compresses; artificial tears 5–6×/day; ocular decongestant (Naphcon-A TDS PRN)
Self-limiting in 2–3 weeks
Highly contagious — strict hygiene (hand washing, disinfect slit lamp); exclude from school/work
No steroids (extend viral shedding; risk if coexisting HSV)
Subepithelial infiltrates (EKC) may persist months → ophthalmology follow-up

🟡 Allergic Conjunctivitis

Cool compresses QDS
Topical olopatadine (combined antihistamine + mast cell stabiliser) — first-line
Artificial tears; avoid allergen
Severe: topical steroid (loteprednol) under ophthalmology supervision only

🟢 Episcleritis

Usually self-limiting in 1–2 weeks
Topical NSAID (ketorolac) or oral NSAID
Artificial tears for comfort
Reassurance; ophthalmology outpatient follow-up if recurrent (may signal systemic disease)

🟢 Scleritis

Oral NSAIDs (indomethacin or naproxen) first-line for diffuse/nodular anterior scleritis
Systemic steroids if unresponsive
Urgent ophthalmology — necrotising scleritis requires immunosuppression
Investigate for systemic inflammatory disease (RA, GPA, SLE)

🟢 Subconjunctival Haemorrhage

Reassurance only — resolves in 2 weeks
Check BP
Coagulation studies if recurrent or spontaneous/bilateral in young patient

🟢 UV Keratitis (Welder's Flash / Snow Blindness)

Oral analgesia (NSAIDs) — symptoms may peak 6–12 hours after exposure
Topical antibiotic (erythromycin ointment) as lubricant
Cycloplegic (cyclopentolate) if significant photophobia
No patching; heals within 24–48 hours
Reassurance

Step 7 — Disposition

Disposition	Indications
Immediate ophthalmology to ED / admit	Chemical burn (grade ≥2), open globe, orbital compartment syndrome, endophthalmitis, gonococcal corneal melt, acute angle-closure
Emergency ophthalmology same visit	Corneal ulcer, HSV dendrite, HZO with ocular signs, hyphaema, orbital cellulitis
Next-day ophthalmology	Iritis (first episode), corneal abrasion not improved
Outpatient ophthalmology within 1 week	Recurrent uveitis, scleritis, viral keratoconjunctivitis, episcleritis
Discharge, GP follow-up	Simple viral/bacterial/allergic conjunctivitis, subconjunctival haemorrhage, UV keratitis

Key Pitfalls

Not staining the cornea → missing HSV dendrite or corneal abrasion
Giving topical steroids without excluding HSV → geographic ulceration, vision loss
Delaying irrigation in chemical burns → every second increases depth of injury
Missing acute angle-closure presenting as headache/nausea without prominent eye complaint (referred to neurology)
Missing open globe — do NOT measure IOP if globe rupture is suspected; gentle examination only
Missing gonococcal conjunctivitis as ordinary bacterial conjunctivitis → corneal perforation within hours
Prescribing topical anaesthetics for home use — inhibit corneal healing and mask worsening
Missing endophthalmitis in post-op patients — any pain/redness after recent ocular surgery = endophthalmitis until proven otherwise

Sources: Tintinalli's Emergency Medicine (Tables 241-2, 241-3, 241-6), Rosen's Emergency Medicine 9th Ed. (Ch. 18 — Table 18.1, Management Algorithm), Kanski's Clinical Ophthalmology 10th Ed., The Wills Eye Manual.

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