Differential Diagnosis for Periorbital Cellulitis, Orbital Cellulitis, and a Sty

When differentiating between periorbital cellulitis, orbital cellulitis, and a sty, it's crucial to consider the clinical presentation, symptoms, and potential complications of each condition. Here's a structured approach to the differential diagnosis:

• Single Most Likely Diagnosis
  • Periorbital cellulitis: This is often the first consideration due to its relatively common occurrence, especially in children, following an upper respiratory infection. It presents with eyelid swelling, redness, and warmth, usually without significant proptosis or vision changes.
• Other Likely Diagnoses
  • Orbital cellulitis: This condition is more severe and involves infection of the orbital tissues posterior to the orbital septum. Symptoms include proptosis, limited eye movement, vision changes, and significant pain. It's a likely diagnosis when there are signs of deeper orbital involvement.
  • Sty (Hordeolum): A sty is an acute, localized infection or inflammation of the eyelid margin involving hair follicles of the eyelashes (external hordeolum) or meibomian glands (internal hordeolum). It presents as a painful, swollen nodule on the eyelid.
• Do Not Miss Diagnoses
  • Cavernous sinus thrombosis: Although rare, this condition is potentially life-threatening and can arise as a complication of orbital cellulitis. Symptoms include bilateral eye involvement, cranial nerve palsies, and signs of increased intracranial pressure.
  • Meningitis: In rare cases, especially in children, orbital or periorbital infections can lead to intracranial complications like meningitis, presenting with fever, headache, stiff neck, and altered mental status.
• Rare Diagnoses
  • Dacryocystitis: An infection of the lacrimal sac, which can present with swelling and tenderness over the lacrimal sac area, and possibly purulent discharge.
  • Idiopathic orbital inflammatory disease: A non-infectious inflammation of the orbit that can mimic orbital cellulitis but lacks an infectious cause.

Each of these conditions has distinct clinical features and requires a careful history, physical examination, and sometimes imaging studies for accurate diagnosis and appropriate management.