It is possible to get scarlet fever once and then get it again, but not more than five times. The cause of scarlet fever is an exotoxin from bacteria called erythrotoxin. After one infection, the body’s immune system becomes immune to erythrotoxin, so that the next time the bacteria infect the body, erythrotoxin will not cause a scarlet rash to appear. However, if a bacterium that produces other serotypes of erythrotoxin infects the body, a scarlet rash may still appear, leading to scarlet fever. Therefore, scarlet fever can usually be acquired twice or even three times in a lifetime, but usually not more than five times. The pathogen that causes scarlet fever is a germ, so it can cause a person to become infected repeatedly. When a person is next infected, the scarlet rash may not appear, but fever, sore throat, and even purulent tonsillitis may still occur.