Romana's Sign
A one-sided swelling of the eyelid that signals acute Chagas disease, caused when the Trypanosoma cruzi parasite enters the eye or is rubbed into the conjunctiva by infected bug feces.
This clinical indicator is a unilateral swelling of the eyelid, often appearing as a lopsided puffiness that resembles an enlarged stye. It signals the acute phase of Chagas disease, occurring when the Trypanosoma cruzi parasite enters the eye or is inadvertently rubbed into the conjunctiva via infected bug feces. This distinctive symptom typically manifests shortly after infection if the parasite gains access near the eye.
What this means in real life
A child scratches an insect bite on their cheek near the eye; within days, the eyelid on that side puffs up noticeably while the other eye remains normal, prompting a doctor's visit to rule out infection.
What it isn’t
It is not a permanent eye condition or disease itself, but rather a temporary physical sign that something else—usually an infection or inflammation—is happening nearby. It is not the same as general facial swelling or puffiness from allergies.
Commonly misused online
Social media sometimes conflates it with any eyelid swelling or 'puffy eye,' ignoring that the sign specifically refers to unilateral swelling linked to systemic infection or parasitic disease, not cosmetic puffiness.