Scarlet fever is an infectious disease caused by the bacteria Streptococcus pyogenes, which also causes strep throat. It primarily affects children and is characterized by a bright red rash, fever, and a sore throat. The rash usually appears 1-2 days after the fever starts and can feel like sandpaper. The disease spreads through respiratory droplets when an infected person coughs or sneezes. Treatment typically involves antibiotics to eliminate the bacteria and reduce symptoms. With proper care, most individuals recover fully within a week, but untreated scarlet fever can lead to complications, such as rheumatic fever or kidney disease.