Contents
Introduction:
This exploration of peri-orbital cellulitis and orbital cellulitis is designed to aid in the diagnosis and management of two distinct but closely related ophthalmological conditions that are commonly managed by both ENT and Ophthalmology services. It aims to provide medical professionals and students with a working understanding of these conditions, including aetiology, presentation, diagnosis, management, and complications.
Overview:
- Peri-orbital cellulitis and orbital cellulitis are non-suppurative soft tissue infections localised around the eye and within the orbital cavity, respectively.
- These conditions may seem similar but in clinical practice require clear distinction due to differences in anatomical involvement, clinical presentation, and management.
- Peri-orbital cellulitis and orbital cellulitis respectively represent the first 2 of the 5 stages of Chandler classification, a system used for delineating the spectrum of eye infections from least to most serious (with the possibility of stage 1 progressing to stage 5, Figure 1).


Figure 1: Chandler’s classification of orbital infection, taken from eyenewsuk with permission from creator Mr Mohammad Farwana. Group I: Peri-orbital (or pre-septal) cellulitis; Group II: Orbital cellulitis; Group III: sub-periosteal abscess; Group IV: Orbital abscess; Group V: Cavernous sinus thrombosis.
Peri-Orbital Cellulitis:
- Peri-orbital cellulitis (also known as pre-septal cellulitis) describes the infection of the tissues anterior to the orbital septum.
- It is most commonly bacterial in origin and arises from cutaneous injury, insect bites, or trauma in the structures around the orbit.
- Presenting features typically include erythema, oedema, pain, and systemic symptoms such as fever and malaise.
Orbital Cellulitis:
- Orbital cellulitis describes a more severe condition that is characterised by infection within the orbit, posterior to the orbital septum.
- Its aetiology typically arises from bacterial infection within the paranasal sinuses or neighbouring structures. It is particularly important to identify the specific aetiology as this will direct very different management and escalation pathways.
- It is clinically distinct from peri-orbital cellulitis due to presenting symptoms including any of severe ocular pain, reduced and/or painful eye movements, proptosis, and vision changes including reduced visual acuity and diplopia.
- Rapid diagnosis and immediate hospitalisation are vital to ensuring favourable clinical outcomes. Intravenous antibiotics are essential. Progression through Chandler’s classification can be swift, and therefore these patients need regular review to assess response to antibiotics and guide decision making on surgical intervention. This would be indicated in specific cases, in particular progression to abscess formation.
Diagnosis and Management:
- Peri-orbital and orbital cellulitis require thorough clinical examination, paying particular attention to both the eye and eye movements. The two presentations can be separated by distinct clinical characteristics (Table 1).
- Assessment should include routine blood tests to determine inflammatory markers, wound swabs and blood cultures to aid antibiotic treatment, and early involvement of both ENT and Ophthalmology teams.
- Accurate and prompt diagnosis is of paramount importance.
- Peri-orbital cellulitis: Prompt initiation of appropriate antibiotics, typically on an outpatient basis given the bacterial aetiology, is essential to preventing progression to orbital cellulitis.
- Orbital cellulitis requires inpatient admission for regular observations, intravenous antibiotics (adjusted based on culture and sensitivity results) and a CT scan with contrast of the brain, orbits and paranasal sinuses.


Table 1: Clinical manifestations of peri-orbital and orbital cellulitis
Conclusion:
Patients presenting with peri-orbital and orbital cellulitis require prompt and accurate diagnosis and early referral to ENT and Ophthalmology to prevent progression to abscess formation, cavernous sinus thrombosis and blindness. A working understanding of the differing presentations and subsequent management strategies between peri-orbital cellulitis and orbital cellulitis is essential for all medical professionals to guide appropriate management.
References and Further Reading
- ENTUK guideline for the child presenting to hospital with preseptal or postseptal orbital cellulitis
- BMJ Best Practice: Peri-orbital and orbital cellulitis
- Orbital cellulitis – an overview of the diagnosis and management (Mr M. Farwana, EYENEWSUK)
- Orbital Cellulitis – EyeWiki
Written by Mr Micheal Edwards ENT CT2 & reviewed by Mr Tobias James ENT ST5
Please also see our other article focussing on these two conditions in the Ophthalmology section of the website
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