Characterized by bright red rashes, fever and sore throat, scarlet fever, or scarlatina, is a transmissible illness caused by a Streptococcus bacterium. It is a mild illness that is rarer and less threatening nowadays than it was in the past, but a scarlet fever outbreak may still lead to severe complications if left untreated. Scarlet fever is a mild disease but it may cause serious health problems.
The specific bacteria behind scarlet fever belong to the gram-positive, beta-hemolytic, group A of Streptococcus, also called Streptococcus pyogenes, or group A strep (GAS). Group A strep is commonly found on the surface of the skin and inside the throat. It is usually passed from one person to another through direct contact with the open wounds, sores, mucus or bodily fluids of an infected person. Not everyone who carries these bacteria will become ill; a streptococcal infection usually occurs if the bacteria get inside the tissues, or if the infected person has a weakened immune system. Some strains of these bacteria can also produce an erythrogenic toxin, which will then cause the hallmark red-colored skin rashes of scarlet fever. Aside from scarlet fever, some of the other mild illnesses that group A strep may cause include strep throat, sinusitis and middle ear infections.
Scarlet fever was once very common in children ages 2 to 10 — when it was associated with deadly epidemics — but now is relatively rare. The development of antibiotics and their early use in the treatment of streptococcal infections has prevented many cases of scarlet fever.