Periorbital cellulitis
Synonyms and keywords: Preseptal cellulitis

# Overview
Periorbital cellulitis is an inflammation and infection of the eyelid and area around the eye. Periorbital cellulitis is also called preseptal cellulitis because it affects the structures in front of the septum, such as the eyelid and skin around the eye. Periorbital cellulitis often occurs from a scratch or insect bite around the eye that leads to infection of the skin. Symptoms can include swelling, redness, pain, and tenderness to touch occurring around one eye only. The affected person is able to move the eye in all directions without pain, but there can be difficulty opening the eyelid, often due to swelling. Also vision is normal.

# Historical Perspective
- Donahue and Schwartz have described 70 cases of periorbital cellulitis from 1986 to 1996 at their institution.

# Classification
- Periorbital cellulitis must be differentiated from orbital cellulitis, which is an infection involving the soft tissues posterior to the orbital septum, including the fat and muscle within the bony orbit ant it is an emergency and sight-threatening situation. In contrast to orbital cellulitis, patients with periorbital cellulitis do not have bulging of the eye (proptosis), limited eye movement (ophthalmoplegia), pain on eye movement, and loss of vision. If any of these features is present, one must assume that the patient has orbital cellulitis and begin treatment with IV antibiotics. CT scan may be done to delineate the extension of the infection.
- Both periorbital cellulitis and orbital cellulitis occur more commonly in children and can present with eyelid inflammation, and distinguishing between the two conditions may be challenging. Hence, the evaluation should include a comprehensive ophthalmic examination, including an assessment of visual acuity, pupillary response, tonometry, anterior segment biomicroscopy, and ophthalmoscopy. A physical examination, including an assessment of routine vital signs, should be performed. Blood cultures should be obtained in patients with concern for systemic toxicity.
- A common cause of preseptal cellulitis is extension of infection from the paranasal sinuses, sinusitis. Other causes include trauma, foreign bodies, insect bites, skin infections (impetigo), eyelid lesions (chalazia, hordeola), and iatrogenic causes such as eyelid and oral procedures. 

# Pathophysiology
- The most common inciting events of periorbital cellulitis include sinusitis specially ethmoiditis, hematogenous seeding, insect bites, periocular or facial trauma, and impetigo. Pathogens spread to nearby tissues through the ophthalmic venous system or the lamina papyracea.
- In a retrospective review of 104 patients with periorbital cellulitis over a 15-year period, the most common predisposing etiologies were acute dacryocystitis (32.6%), sinusitis and upper respiratory infection (28.8%), and recent trauma or surgery (27.8%).

# Causes
- The most common bacterial germs causing periorbital cellulitis are Staphylococcus aureus, Streptococcus pneumoniae, and Streptococcus pyogenes. With increased vaccination, there are fewer cases of Haemophilus influenzae as a causative organism. Less common causes are Acinetobacter, Nocardia, Pseudomonas, Neisseria, Mycobacterium and fungal infections.

# Differentiating periorbital cellulitis from other Diseases
- It is important to differentiate periorbital cellulitis from orbital cellulitis, allergic reactions, orbital tumors, exophthalmos, chalazion and hordeolum.
- In neonatal patients gonorrhoea and Chlamydia infection should be considered.

# Epidemiology and Demographics
- Periorbital cellulitis can occur at any age, but it is common in children and it is more common than orbital cellulitis in this population.

# Risk Factors
- The risk factors include trauma, insect bite, localized or systemic infection and postsurgical.

# Screening
- There is insufficient evidence to recommend routine screening for periorbital cellulitis.

# Natural History, Complications, and Prognosis
- With inadequate treatment, periorbital cellulitis can lead to complications such as orbital cellulitis and loss of vision, subperiosteal abscess, orbital abscess, or cavernous sinus thrombosisand intracranial infection such as intracerebral abscess, meningitis, empyema or abscess of the epidural or subdural space in severe cases.

# Diagnosis

## Diagnostic Study of Choice
- The diagnosis of periorbital cellulitis is mainly a clinical diagnosis with radiologic findings.

## History and Symptoms
- Clinical assessment should evaluate a patients general appearance and local conditions to differentiate periorbital cellulitis with orbital cellulitis. A meticulous examination based on the recognition of distinctive signs, relevant history and an evaluation of predisposing risk factors is essential in diagnosis and expeditious treatment.
- Assessment of visual acuity, pupillary response, examination of the ocular adnexa and globe are paramount.
- Periorbital cellulitis typically presents with eyelid oedema and erythema, features characteristic of cellulitis. The extent of infection is superficial and does not extend posteriorly into the orbit. Hence, patients with periorbital cellulitis will present with normal vision, absence of proptosis, and full ocular motility without pain on movement.

## Physical Examination
- Physical examination, including an assessment of routine vital signs, visual acuity and eye movement. Local examination generally reveals associated symptoms like eyelid and periorbital swelling, tenderness, erythema, warmth, proptosis, ophthalmoplegia, and impaired vision.

## Laboratory Findings
- Blood cultures are not performed routinely. They are difficult to obtain in those with periorbital cellulitis and are usually negative. However, laboratory tests, including assessment of white blood cell counts and serum C-reactive protein levels may be useful in children with fever.

## X-ray
- There are no x-ray findings associated with periorbital cellulitis.

## CT scan
- A CT scan of the orbits and sinuses allows differentiation of the periorbital cellulitis and orbital cellulitis , as well as a way to determine the extent of the infection. The CT scan of periorbital cellulitis shows eyelid swelling, no proptosis, no fat stranding of orbital contents, and no involvement of the extraocular muscles.
- In cases where abscesses are suspected, a brain CT is required to rule out intracranial involvement. A CT scan is also recommended if marked eyelid swelling, fever, leukocytosis, or no improvement after 24 hours of the proper antibiotics.

## MRI
- MRI does not have indication in periorbital cellulitis

## Other Imaging Findings
- There are no other imaging findings associated with periorbital cellulitis.

## Other Diagnostic Studies
- There are no other diagnostic studies associated with ].

# Treatment
- The treatment of periorbital cellulitis differs based on the severity of disease and age of the patient. The mainstay of treatment is usually antibiotic coverage against staphylococcus aureus, the streptococcus species, and anaerobes. Patients who are over one year of age with mild symptoms can be treated as an outpatient with oral antibiotics. However, if the patient does not respond to oral antibiotics in 48 hours or if extension of the infectious process into the orbit is suspected, he or she should be admitted to the hospital and a CT scan must be performed to evaluate for orbital extension, and intravenous antibiotics must be indicated. Those with more severe disease or are less than one year of age, should be admitted to the hospital.
- Usually children under 2 years of age or febrile patients with a severe cellulitis are managed with intravenous antibiotics during hospitalization, with close followup. Hospitalization is also recommended in patients who cannot be followed up as outpatients. Intravenous antibiotics are usually indicated for two or three days, depending on improvement. If the condition improves, treatment can be switched to the appropriate oral antibiotics based on cultures.

## Medical Therapy
- Periocular infection
- 1. Causative pathogens
- Streptococcus spp.
- Methicillin-sensitive Staphylococcus aureus (MSSA)
- Methicillin-resistant Staphylococcus aureus (MRSA)
- Hemophilus influenzae
- 2. Empiric antimicrobial therapy
- Preferred regimen (1): Clindamycin 300-450 mg PO q6h for 1-2 weeks or Clindamycin 600-900 mg IV q8h for 1-2 weeks
- Preferred regimen (2): Daptomycin 4 mg/kg IV qd for 1-2 weeks
- Alternative regimen (1): Trimethoprim/Sulfamethoxazole 160 mg PO q12h for 1-2 weeks or  Trimethoprim/Sulfamethoxazole 2.5 mgkg IV q12h for 1-2 weeks
- Alternative regimen (2): Doxycycline 100 mg IV or PO q12h for 1-2 weeks
- Alternative regimen (3): Linezolid 600 mg IV or PO q12h for 1-2 weeks
- Alternative regimen (4): Vancomycin 1 g IV q12h for 1-2 weeks
- 3. Pathogen-directed antimicrobial therapy
- 3.1 Methicillin-resistant Staphylococcus aureus
- Preferred regimen (1): Vancomycin 1 g IV q12h for 1-2 weeks
- 3.2 Non-MRSA organisms
- Preferred regimen (1): Clindamycin 300-450 mg PO q6h for 1-2 weeks OR Clindamycin 600-900 mg IV q8h for 1-2 weeks
- Preferred regimen (2): Daptomycin 4 mg/kg IV qd for 1-2 weeks
- Alternative regimen (1): Trimethoprim/Sulfamethoxazole 160 mg PO q12h for 1-2 weeks OR  Trimethoprim/Sulfamethoxazole 2.5 mgkg IV q12h for 1-2 weeks
- Alternative regimen (2): Doxycycline 100 mg IV or PO q12h for 1-2 weeks
- Alternative regimen (3): Linezolid 600 mg IV or PO q12h for 1-2 weeks

## Surgery
- If medical therapy fails to show improvement after 24 to 48 hours, patients should be hospitalized and a surgical consultation should be considered for possible incision and drainage. Surgical drainage and debridement of a lid abscess can be performed by a small incision through the skin over an area of fluctuance.
- In patients with subperiosteal abscess, orbital abscess and cavernous sinus thrombosis surgery is necessary for drainage. Loculations within the cavity of the abscess must be broken, and packing of the wound should be considered to promote further drainage.

## Primary Prevention
- There are no established measures for the primary prevention of periorbital cellulitis.

## Secondary Prevention
- There are no established measures for the secondary prevention of periorbital cellulitis.