Conjunctival suffusion is a medical term referring to a condition where the conjunctiva—the thin, transparent layer covering the white part of the eye and the inner eyelids—becomes red and swollen. It often looks like conjunctivitis (pink eye) but is distinct because it typically lacks the inflammatory discharge or crusting associated with infections. This condition is most commonly linked to leptospirosis, a bacterial infection caused by Leptospira interrogans, which humans can contract from contact with water or soil contaminated by infected animals. It usually appears early in the illness, often alongside symptoms like fever, headache, and muscle pain, and is seen in about 30% of leptospirosis cases. It can also occur in other conditions, such as Hantavirus infection.
The redness comes from dilated blood vessels in the conjunctiva, and swelling (chemosis) may be noticeable, especially at the corners of the eye. Unlike typical conjunctivitis, it doesn’t usually involve pus or a gritty sensation. In leptospirosis, it tends to show up toward the end of the early phase of the disease and resolves as the illness progresses or is treated.