Scarlet fever is a bacterial infection that causes a bright red rash across the body, along with a sore throat and high fever. The rash feels like sandpaper and often starts on the chest before spreading to other parts of the body. The tongue may turn bright red and bumpy, which doctors call “strawberry tongue.”

It mostly affects children between ages 5 and 15. Before antibiotics were widely available, scarlet fever was a serious and sometimes deadly disease that parents greatly feared. Today, doctors can treat it with antibiotics like penicillin, and most children recover completely within a week or two.

The same bacteria that causes strep throat causes scarlet fever. Not everyone who gets strep throat develops the rash, though. The disease spreads through coughing, sneezing, or sharing cups and utensils with someone who's infected.

You might encounter scarlet fever in classic novels like The Velveteen Rabbit or Little Women, where characters become seriously ill with it. These stories remind us how much medicine has advanced: what once threatened lives is now a treatable infection.