conjunctival suffusion

The finding is a diffuse injection of the bulbar conjunctiva, often with chemosis, sparing the limbus and unaccompanied by the discharge that characterizes infective conjunctivitis. Its diagnostic value lies in the company it keeps: in a patient with abrupt fever, severe myalgia especially of the calves and lumbar region, headache, and a history of exposure to fresh water, floodwater, or animal urine, conjunctival suffusion strongly suggests leptospirosis. It occurs in the initial leptospiraemic phase, usually within the first few days. Other causes of a red eye without discharge include Kawasaki disease, where bilateral non-exudative bulbar conjunctival injection is a diagnostic criterion alongside fever, oral changes, rash, extremity changes, and cervical lymphadenopathy, and also measles, adenovirus, and toxic shock syndrome. Recognizing suffusion matters because early doxycycline or penicillin in leptospirosis prevents progression to Weil disease, and because prompt IVIG in Kawasaki disease prevents coronary artery aneurysms.