Preseptal Cellulitis

Where the infection is: preseptal vs orbital

The orbital septum is a thin membrane that runs from the rim of the eye socket into the eyelids. It acts as a firewall:

• In front of the septum (preseptal): eyelid skin and soft tissue. Infection here is uncomfortable but rarely dangerous.
• Behind the septum (orbital): the fat and muscles surrounding the eyeball, and the optic nerve. Infection here can threaten vision and spread to the brain.

The septum is thinner and less developed in young children, so infection can cross it more easily. Doctors therefore look carefully for signs that the infection has gone deeper. The general symptoms and course are covered on the periorbital cellulitis page; this page focuses on how clinicians decide where the infection is and how to treat it.

Telling preseptal from orbital cellulitis

Because a swollen child may not cooperate, the doctor may need to gently hold the lids open to check movements and vision. If this is impossible, imaging is usually ordered.

Mimics: not every swollen eyelid is infection

• Allergic swelling: puffy, pale or pink, itchy and not tender, often both eyes, after pollen, cosmetics or pet contact.
• Insect bite reaction: marked swelling with itch but little tenderness. Morning swelling after a bite on the eyelid is common and usually not infection.
• Stye or chalazion: a tender or painless lump at the lid margin; can lead to preseptal cellulitis if the surrounding lid becomes red and swollen.
• Conjunctivitis: red eye with discharge and mild lid puffiness; the lid is not hot or very tender.
• Dacryocystitis: a red, painful swelling at the inner corner of the eye, from an infected tear sac.
• Swelling from kidney disease or other causes: usually both eyes, painless.

Causes

• Sinusitis: the most common source in children. Infection from the ethmoid sinuses, behind the bridge of the nose, spreads to the eyelid. See acute sinusitis.
• Local skin breaks: insect bites, scratches, chickenpox spots, impetigo, eczema.
• Eyelid lesions: infected styes and chalazia.
• Injury or surgery around the eye.
• Bacteria: usually Staphylococcus aureus (including MRSA in some areas) and streptococci. Haemophilus influenzae type b was once a major cause in young children, but the Hib vaccine has made it rare.

How it is diagnosed

Diagnosis is made by examination. Doctors check vision, pupils, eye movements, eye position and whether the patient is generally unwell. Blood tests are not routinely needed for mild cases.

A CT scan of the orbits and sinuses with contrast is recommended when:

• eye movement is painful or restricted, or the eye bulges
• vision is reduced or color vision is abnormal
• the eye cannot be examined because of swelling
• there is no improvement after 24 to 48 hours of IV antibiotics
• there are signs of brain involvement

Treatment

Mild to moderate cases

Oral antibiotics, typically for 5 to 10 days, chosen to cover staph and strep and, where common, MRSA. Common choices include amoxicillin-clavulanate or cephalexin, with clindamycin or trimethoprim-sulfamethoxazole added or substituted if MRSA is a concern. The patient should be reviewed within 24 to 48 hours.

When hospital treatment is needed

• infants under 1 year, and especially under 3 months
• a child who is unwell, not drinking, or has a high fever
• failure to improve on oral antibiotics
• any sign of orbital involvement
• uncertainty about follow-up

IV antibiotics are given until clear improvement, then switched to tablets or liquid to complete the course.

Supportive care

• Warm compresses several times a day.
• Pain and fever relief with acetaminophen (paracetamol) or ibuprofen, following the label dose. Do not give aspirin to children or teenagers.
• Raising the head of the bed reduces swelling.
• Treat the cause: nasal saline and sometimes nasal steroids for sinusitis, warm compresses for a stye.

Recovery and complications

Swelling usually starts improving within 24 to 48 hours of antibiotics and resolves within about a week. Complications are uncommon but include abscess formation in the eyelid needing drainage, and progression to orbital cellulitis. Rarely, infection spreads to the brain or causes cavernous sinus thrombosis.

Frequently asked questions

What is the difference between preseptal and orbital cellulitis?

Preseptal cellulitis affects the eyelid and skin in front of the orbital septum; the eye moves normally and vision is unaffected. Orbital cellulitis involves the tissues behind the septum, causing pain with eye movement, restricted movement, bulging and sometimes vision loss. Orbital cellulitis is an emergency requiring hospital treatment.

How is preseptal cellulitis treated?

Most cases are treated with oral antibiotics for 5 to 10 days, plus warm compresses and pain relief, with a check-up within 1 to 2 days. Babies, very unwell children, and people not improving on tablets need IV antibiotics in the hospital and sometimes a CT scan.

How long does it take for preseptal cellulitis to go away?

Redness and swelling usually begin to improve within 24 to 48 hours of starting antibiotics and settle within about 5 to 7 days. Finish the full course even if the eyelid looks normal. If it is not improving after 48 hours, return for review.

Is preseptal cellulitis contagious?

The cellulitis itself is not usually spread between people. The bacteria that cause it, or the cold or sinus infection that triggered it, can be passed on, so good handwashing and not sharing towels are sensible.

Can a bug bite cause preseptal cellulitis?

Yes, though most eyelid swelling after a bite is an allergic reaction, which is itchy, pale and not very tender. Cellulitis is suggested by increasing redness, warmth, tenderness and fever developing a day or more after the bite. If unsure, have it checked.