Definition Scarlet fever is a relatively rare infection. It affects people who have a throat or skin infection caused by certain strains of the group A streptococcus bacteria.
What is going on in the body? Scarlet fever usually occurs after a throat infection with Streptococcus bacteria, such as strep throat. However, it may also occur after a strep skin infection. The bacteria that cause scarlet fever make a toxin that results in a skin rash. The rash usually spreads over most of the body, only to peel off a week later.
This condition is now uncommon because of the regular use of antibiotics for strep infections.
What are the signs and symptoms of the infection? The rash associated with scarlet fever usually starts on the neck, chest, armpits, and groin. Within a day, it usually spreads to the rest of the body. The rash is usually made up of a series of tiny pinkish-red spots and feels like sandpaper. About a week later, the rash usually peels off, much as the top layer of skin does after a sunburn. Other signs and symptoms may include:
swollen and red tongue, known as strawberry tongue
What are the causes and risks of the infection? Scarlet fever is caused by an infection with a strain of strep bacteria that makes the scarlet fever toxin. Strep throat is usually spread person-to-person through coughing or sneezing. Strep skin infections are usually caused by contact with infected skin.
Those at highest risk for scarlet fever are:
children older than 3 years old
people living in overcrowded environments, such as day care, school, or military camps
people who have been in contact with someone who has a strep throat or skin infection
What can be done to prevent the infection? Early treatment of strep infections with antibiotics can prevent this condition. Scarlet fever was much more common before antibiotics were widely used.
How is the infection diagnosed? The diagnosis is often suspected after a medical history and physical examination are done. A test for strep is often done by swabbing the back of the throat to get a sample of the bacteria growing there. With a test called ELISA or "quick strep", the diagnosis can often be made from the swab within a few minutes.
A throat culture of the bacteria may also be done. This involves the same swabbing method, but the swab is put inside a special container. Inside the container is a substance that helps the bacteria to grow. If bacteria grow, the laboratory can identify them as strep. The culture often takes at least 24 hours to grow bacteria.
What are the long-term effects of the infection? In most cases, there are no long-term effects. Rarely, kidney or heart damage may occur from the strep infection. These are known as poststreptococcal glomerulonephritis, which affects the kidney, and rheumatic fever, which affects the heart. Both of these conditions permanently damage the body.
What are the risks to others? This infection is contagious and poses a risk to others. It is best not to share drinking glasses or utensils with someone who has a strep infection. Frequent hand-washing can also help prevent spread of this infection.
What are the treatments for the infection? The most important part of treatment is antibiotics. Medications from the penicillin class, such as penicillin or amoxicillin, are commonly used. Paracetamol can be used for fever, headache, or throat pain, as needed.
What are the side effects of the treatments? Antibiotics and paracetamol may cause allergic reactions and stomach upset.
What happens after treatment for the infection? Antibiotics almost always cure this condition. The skin quickly returns to normal once the rash peels off. In very rare cases, a person will need long-term treatment for heart or kidney damage from the infection.
How is the infection monitored? Adults can usually monitor themselves or their children at home. If symptoms do not start to improve within 2 to 3 days or get worse, the doctor should be contacted. Any new or worsening symptoms should also be reported to the doctor.
Author: John Riddle Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
