What are the symptoms of measles?

Measles begins with 3–4 days of high fever (often above 40°C/104°F), cough, runny nose (coryza), and red, watery eyes (conjunctivitis) — known as the '3 Cs'. A key early sign is Koplik's spots: tiny white or grey-blue dots on the inside of the cheeks, appearing 1–2 days before the rash and pathognomonic (unique) to measles. The hallmark maculopapular rash then starts at the hairline and face, spreading downward to the trunk and limbs over 3 days. Fever peaks when the rash appears, then gradually falls if the illness is uncomplicated. Complications include ear infections (about 1 in 10 children), pneumonia (the leading cause of measles deaths), and, rarely, encephalitis (1–2 per 1,000 cases). A lesser-known long-term risk is immune amnesia: measles can wipe out 11–73% of existing antibody memory for 2–3 years, leaving recovered individuals more susceptible to other infections.