Differential Diagnosis for Unilateral Periorbital Eye Swelling with No Erythema
- Single Most Likely Diagnosis
- Allergic reaction (e.g., from an insect bite or allergen exposure): This is a common cause of unilateral periorbital swelling without erythema, often presenting with itching and a history of exposure to an allergen.
- Other Likely Diagnoses
- Thyroid eye disease: Although it can be bilateral, thyroid eye disease can present unilaterally and may cause periorbital swelling due to inflammation of the tissues around the eye.
- Orbital cellulitis (early stages): While typically associated with erythema, in the early stages, orbital cellulitis might present with swelling alone, especially if the infection is not yet severe.
- Chalazion or hordeolum (stye): These are localized infections or blockages of the meibomian glands or eyelid margin, respectively, which can cause swelling but might not always be accompanied by significant erythema.
- Do Not Miss Diagnoses
- Orbital tumor (e.g., lymphoma, metastasis): Although rare, these conditions can cause unilateral swelling and must be considered to avoid delayed diagnosis and treatment.
- Cavernous sinus thrombosis: A potentially life-threatening condition that can present with unilateral periorbital swelling, among other symptoms like headache and visual disturbances.
- Carotid-cavernous fistula: An abnormal connection between the carotid artery and cavernous sinus, which can lead to unilateral periorbital swelling due to venous congestion.
- Rare Diagnoses
- Sarcoidosis: A systemic disease that can affect the orbits and cause swelling, though it's less common and usually part of a broader clinical picture.
- Wegener's granulomatosis (Granulomatosis with Polyangiitis): A rare autoimmune disorder that can affect various parts of the body, including the orbits, leading to swelling and other symptoms.
- Amyloidosis: Deposits of amyloid protein can accumulate in the orbit, causing swelling, though this is exceedingly rare and usually part of a systemic condition.