What Is Scarlet Fever?

Scarlet fever is an infection caused by group A streptococcus (group A strep), the same bacteria responsible for strep throat. Also known as scarlatina, it's characterized by a rash and a red tongue. It's most likely to strike children between ages 5 and 15 and rarely, if ever, affects adults. Although once a dangerous disease of childhood, scarlet fever is now highly treatable and uncommon in most of the world.

Scarlet Fever Symptoms

Scarlet fever typically begins with a fever, sore throat, and other familiar symptoms of a strep infection, such as a headache and chills.

After day two, a sandpapery rash appears on the skin, which helps to distinguish scarlet fever from garden-variety strep throat. The rash will persist for some time after the initial symptoms of scarlet fever respond to treatment. Sometimes the skin on certain areas of the body will peel for a few weeks. 

Although not common, scarlet fever can develop after a strep infection of the skin such as impetigo. Rather than beginning as a throat infection, scarlet fever would begin with signs of infection around a burn or wound.

Causes

Group A strep bacteria are responsible for many types of infections, including strep throat and certain skin infections. The bacteria that belong to the strain of group A strep that causes scarlet fever produce a toxin that's responsible for the red rash and "strawberry tongue" that are unique characteristics of the illness.

Group A strep bacteria travel via droplets of infected fluid that become airborne when an infected person coughs or sneezes. Touching something that the bacteria have landed on and then touching your mouth, eyes, or nose can cause you to become infected.

Diagnosis

Scarlet fever is diagnosed in the same way as strep throat. A throat swab is taken and either a rapid strep test is performed or the sample is cultured to see if the streptococcus bacteria is present. The rapid test can show a positive result within five to 10 minutes, but the results from a culture may take up to two days. Both tests will often be performed because the rapid tests can be unreliable.

Treatment

There are two important aspects of treating scarlet fever—killing the bacteria and easing symptoms.

For dealing with the uncomfortable and sometimes painful symptoms of scarlet fever, there are a variety of home remedies and over-the-counter (OTC) remedies. These include simple approaches to easing a sore throat such as eating cold foods, drinking warm liquids, and using a room to keep the air moist. Non-steroidal anti-inflammatory drugs (NSAIDs) can bring down fever and ease general body aches and pains. 

A Word From Verywell

Scarlet fever was once a very dangerous and common disease of childhood. In the 19th century, it was responsible for the deaths of many children. Now that it can be treated easily and effectively, it's no longer the threat it once was. There have been some outbreaks in recent years, however. Beginning in 2014, rates of scarlet fever began to increase in England and East Asia, for example, according to a 2018 report in The Lancet.

Researchers aren't sure what's behind the rise in scarlet fever in these countries, although it's thought that resistance to certain antibiotics may have played a role in Asia. But despite the resurgence of scarlet fever in particular regions of the world, it's important to note that this illness is no longer the common scourge of childhood it once was.