Periorbital and Orbital Cellulitis

Article Last Updated:26/05/2026

Periorbital and Orbital Cellulitis

Periorbital cellulitis, also known as preseptal cellulitis, is an infection of the eyelid and periocular tissues anterior to the orbital septum.

It must be distinguished from orbital cellulitis, which involves infection posterior to the orbital septum and is a sight-threatening emergency.

This updated UKMLA guide covers: periorbital cellulitis vs orbital cellulitis, causes, risk factors, symptoms, complications, diagnosis, and management.

Causes and Risk Factors

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Feature	Periorbital (preseptal) cellulitis	Orbital (postseptal) cellulitis
Definition	Infection of the eyelid and periocular structures anterior to the orbital septum (outside the orbit) The orbit itself is NOT affected	Infection posterior to the orbital septum (inside the orbit) involving the extra-ocular muscles, orbital fat, peri-orbital soft tissue +/- optic nerve This is a sight-threatening emergency.
Causes	Local trauma (e.g. insect bites, minor lacerations and abrasions) Contiguous spread from sinusitis (esp. ethmoid) Haematogenous spread	Bacterial rhinosinusitis (co-exists in up to 98% cases, esp. ethmoid sinus) Dental or middle ear infections Orbital trauma / fractures Ophthalmic surgeries Untreated periorbital cellulitis can progress into orbital cellulitis
Organisms	Staphylococcus aureus Streptococcus pneumoniae Streptococcus pyogenes	Staphylococcus aureus Streptococcus pneumoniae
Risk factors	Young children (<5 y/o) Lack of immunisation Immunocompromised	Young children (but usually older than children with periorbital cellulitis) Immunodeficiency is a major risk factor, especially for rare fungal or mycobacterial infections

Clinical Features

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Feature	Periorbital (preseptal) cellulitis	Orbital (postseptal) cellulitis
Definition	Infection of the eyelid and periocular structures anterior to the orbital septum (outside the orbit) The orbit itself is NOT affected	Infection posterior to the orbital septum (inside the orbit) involving the extra-ocular muscles, orbital fat, peri-orbital soft tissue +/- optic nerve This is a sight-threatening emergency.
Eyelid	Swelling and erythema Tenderness around the eye
Proptosis	Absent	Present (key distinguishing feature)
Vision	Normal	Affected (decreased / impaired visual acuity or colour vision) RAPD (Marcus Gunn pupil) possible
Eye movement	Normal	Affected, may present as: Ophthalmoplegia (restricted extraocular motility) Diplopia Pain with eye movement
Chemosis and conjunctival injection	Less common	Present
Systemic toxicity	Less common	Fever is often present

Complications

Periorbital cellulitis ^[Ref]	Orbital cellulitis ^[Ref]
Isolated periorbital cellulitis rarely causes serious complications when identified and treated promptly If inadequately managed, possible complications: Progression to orbital cellulitis Ocular necrotising fasciitis Systemic infection (e.g. bacteriaemia, sepsis)	Orbital cellulitis carries a much higher risk of complications: Abscess formation (subperiosteal or orbital abscess – which can exert pressure on the optic nerve) Vision loss Intracranial extension (via valveless facial and ophthalmic venous system into the CNS) Cavernous sinus thrombosis Meningitis Brain abscess

Periorbital cellulitis ^[Ref]

Orbital cellulitis ^[Ref]

Isolated periorbital cellulitis rarely causes serious complications when identified and treated promptly

If inadequately managed, possible complications:

Progression to orbital cellulitis
Ocular necrotising fasciitis
Systemic infection (e.g. bacteriaemia, sepsis)

Orbital cellulitis carries a much higher risk of complications:

Abscess formation (subperiosteal or orbital abscess – which can exert pressure on the optic nerve)
Vision loss
Intracranial extension (via valveless facial and ophthalmic venous system into the CNS)
- Cavernous sinus thrombosis
- Meningitis
- Brain abscess

The Chandler classification is a staging system used to categorise the complications of periorbital and orbital cellulitis based on their severity (from least to most severe):

Group 1: periorbital cellulitis
Group 2: orbital cellulitis
Group 3: subperiosteal abscess
Group 4: orbital abscess
Group 5: cavernous sinus thrombosis

Investigation and Diagnosis

All suspected cases of orbital cellulitis should be referred to hospital, as it is a potentially sight-threatening emergency.

Consider referring or seeking specialist advice for periorbital cellulitis, or cellulitis near the eyes or nose.

Imaging is not routinely required for uncomplicated preseptal cellulitis if the eye can be examined properly and there are no features of orbital involvement.

Urgent CT orbit, sinuses, and brain is required if:

Orbital cellulitis is suspected (see clinical features section above), or
Unable to examine eye / open eyelids, or
Failed to improve with medical therapy

CT is used to assess for post-septal orbital involvement (which differentiates orbital cellulitis from periorbital cellulitis), sinus disease, subperiosteal/orbital abscess, and intracranial complications.

Management

All suspected cases of orbital cellulitis should be referred to hospital, as it is a potentially sight-threatening emergency.

Consider referring or seeking specialist advice for periorbital cellulitis, or cellulitis near the eyes or nose.

Disclaimer:

There is no single universal UK guideline (e.g. NICE) for the management of periorbital and orbital cellulitis. This section summarises high-yield principles from ENT UK and NHS Scotland. Exact antibiotic choice, imaging thresholds and admission criteria vary by local policy and should be guided by local ophthalmology, ENT and microbiology advice.

Periorbital Cellulitis

Consider treating as an outpatient

Oral co-amoxiclav
Review in eye casualty in 24-48 hours

Orbital Cellulitis

Key management principles:

Admit to hospital urgently
IV antibiotics
- Choice depends on local antimicrobial guidance and microbiology advice
- Example regimens may include broad-spectrum IV antibiotics such as:
  - IV co-amoxiclav
  - IV piperacillin/tazobactam
  - IV ceftriaxone + IV flucloxacillin + oral / IV metronidazole
Urgent ophthalmology / ENT input