Scarlet Fever Facts and History
Scarlet fever is a bacterial infection. The distinctive feature of scarlet fever is a sore throat followed by a rash made up of tiny pinkish-red spots that cover the whole body.
- Scarlet fever (sometimes referred to as scarlatina) is an infectious disease characterized by fever, sore throat (pharyngitis), and a characteristic rash.
- Scarlet fever is caused by an infection with group A Streptococcus, the same bacteria responsible for causing "strep throat" and various other skin infections (for example, impetigo and erysipelas).
- Scarlet fever is predominantly a childhood disease occurring in children 2-10 years of age, though it can less commonly occur in older children and adults.
- The incidence and mortality rates associated with this once-feared disease have significantly decreased due to the introduction and widespread use of antibiotics.
- Because it is so contagious, scarlet fever historically has been responsible for devastating epidemics, particularly in the 19th century. In 1923, the husband and wife team of George and Gladys Dick identified the streptococcal bacterium responsible for causing scarlet fever, and shortly thereafter they isolated the toxin responsible for causing the characteristic rash of scarlet fever. This led to the development of a test once used to determine an individual's immunity or susceptibility to scarlet fever and to the development of a patented vaccine.
- The vaccine is no longer used, as its use was eliminated by the use of antibiotics.
What Are the Symptoms and Signs of Scarlet Fever?
The symptoms and signs of scarlet fever usually begin one to four days after exposure to the streptococcal infection (incubation period). As previously mentioned, scarlet fever typically occurs in association with a pharyngeal streptococcal infection, therefore many of the symptoms and signs initially will be similar to that of strep throat and may include any of the following:
Approximately one to four days after the onset of illness, a characteristic skin rash will appear with the following properties.
- The rash typically begins on the chest, neck, and armpit area and then spreads to other areas of the body.
- The rash is often more pronounced and reddened in areas of skin creases, such as the axilla, the neck, the inguinal area, and in the creases of the elbow (antecubital fossa) and the knee (popliteal fossa). Ruptured capillaries in these areas may cause the resultant rash to appear as lines (termed Pastia lines).
- The rash is described as fine and rough-textured (like sandpaper), consisting of multiple red punctate lesions. The rash blanches when pressed upon.
- The face may appear flushed, and the area around the mouth may appear pale (circumoral pallor).
- The rash may last anywhere between two to seven days. After the rash has faded, the skin begins to peel (desquamation), and this may last up to several weeks. The extent and duration of skin peeling are directly related to the initial severity of the rash. Areas commonly affected include the fingers, toes, palms, axilla, and groin.
- During the first one to two days of illness, the tongue may have a white-colored coating with protruding, swollen, and red papillae on the surface. After about four to five days, the white coating sloughs off revealing a red-colored tongue with prominent papillae (strawberry tongue).
What Causes Scarlet Fever?
Scarlet fever is caused by infection with exotoxin-producing group A beta-hemolytic streptococci (GABHS), notably Streptococcus pyogenes.
- The release of a particular toxin is responsible for the characteristic scarlet-colored rash seen with scarlet fever (giving the disease its name).
- In the majority of cases, scarlet fever occurs as a result of a pharyngeal streptococcal infection (strep throat), though it can less commonly occur as a result of streptococcal infections at other sites, such as the skin.
- It is estimated that scarlet fever develops in up to 10% of individuals who develop streptococcal pharyngitis.
- Scarlet fever can occur at any time of the year, though it is more common during the winter and spring.
- The streptococcal bacterium is typically spread via airborne respiratory droplets transmitted by infected individuals or by individuals who carry the bacteria but do not experience any symptoms (asymptomatic carriers).
- Streptococcal infections can also be transmitted by coming in direct contact with infected secretions and rarely by food-borne outbreaks.
- Transmission is enhanced in crowded environments in which individuals come in close contact with each other (for example, schools or day-care centers).
When Should I Call a Doctor about Scarlet Fever?
You should contact your healthcare provider if you have a sore throat, especially if it is associated with a fever or a rash. Though most cases of sore throat are caused by a viral infection, your healthcare provider will need to confirm that you do not have "strep throat" and scarlet fever, which are illnesses that require prescription medications (antibiotics) to prevent potential complications and shorten the disease.
How Is Scarlet Fever Diagnosed?
The diagnosis of scarlet fever can be made by your healthcare provider utilizing information obtained from your medical history, physical exam, and laboratory testing.
- Because the majority of cases of scarlet fever are associated with strep throat, your healthcare provider may gently swab the back of the throat and tonsils using a cotton swab to evaluate for this illness.
- A rapid antigen detection test sometimes referred to as a rapid strep test, may provide results within several minutes, while a throat culture (which is more sensitive) may require 24-48 hours before the results are available.
- In some cases, your healthcare provider may choose to obtain blood work. A complete blood count may demonstrate evidence of infection, and streptococcal antibody testing (for example, the antistreptolysin O test) can provide evidence of a previous streptococcal infection, though this test is not useful in the acute phase of the illness.
- Finally, in the uncommon scenario that the streptococcal infection is arising from an alternative site, appropriate evaluation and testing of these areas to confirm a streptococcal infection needs to be undertaken.
What Is the Treatment for Scarlet Fever?
- Antibiotics are the cornerstone of treatment for scarlet fever, and they are generally curative.
- Antibiotics not only prevent the potential complications associated with streptococcal infection (for example, acute rheumatic fever), but they also shorten the duration of symptoms (by up to one day) and decrease contagiousness.
- In general, individuals with scarlet fever are not contagious after taking antibiotics for at least 24 hours.
- The most commonly used antibiotics include either oral penicillin VK for 10 days or the administration of a one-time intramuscular injection of penicillin G benzathine.
- Alternative antibiotics include the first-generation cephalosporin drug class. For those individuals allergic to penicillin, erythromycin (E.E.S. Granules, E.E.S.-200, E.E.S.-400, E.E.S.-400 Filmtab, EryPed, EryPed 200, EryPed 400, Ery-Tab, Erythrocin Stearate Filmtab, PCE Dispertab) is recommended.
- It is very important to complete the full course of antibiotics prescribed to you, as early cessation of antibiotics can lead to an inadequately treated infection, thus increasing the risk of possibly developing potential complications.
Are There Home Remedies for Scarlet Fever?
After being diagnosed with scarlet fever, there are various measures that can help alleviate the symptoms and hasten recovery at home. The vast majority of cases of scarlet fever can be managed at home unless the rare serious complications of the disease develop.
- Individuals with scarlet fever can take over-the-counter medications such as acetaminophen (Tylenol) or ibuprofen (Advil or Motrin) for pain control and fever reduction.
- Adequate rest and increased fluid intake are also important for promoting more rapid recovery.
- If pharyngitis is present, various throat lozenges can provide temporary relief for a minor sore throat. Gargling with warm salt water may also be helpful.
What Is the Follow-up for Scarlet Fever?
A follow-up visit with your healthcare provider is recommended to make sure that your recovery is complete and without complications. If you have been diagnosed with scarlet fever and you are not improving or if your symptoms are worsening, you must consult your healthcare provider promptly.
Immediate treatment with an antibiotic after a positive rapid strep test may not always make you well faster. but it will shorten the time you are able to spread the disease to others. Antibiotics also lower the risk of the infection spreading to other parts of your body. There is no harm in delaying medicine treatment 1 to 2 days to wait for the results of a throat culture. Antibiotics will prevent rheumatic fever even if it is started up to 9 days after symptoms begin
How Can I Prevent Scarlet Fever?
- The best preventative measure against scarlet fever is early and appropriate treatment with antibiotics for group A streptococcal infection. This will significantly decrease or eliminate an individual's chances of developing scarlet fever.
- The introduction and widespread use of antibiotics has been the most important factor in diminishing the cases of scarlet fever.
- Minimizing the risk of transmitting group A streptococcal infection is also important.
- Try to avoid close contact with individuals who have been diagnosed with strep throat, and avoid sending children to school or daycare until they have been treated with antibiotics for at least 24 hours.
- Those individuals diagnosed with strep throat should try to avoid spreading the disease to others by maintaining good hygiene practices (wash hands frequently, use separate utensils and cups, and cover the mouth and nose when coughing or sneezing).
What Is the Prognosis for Scarlet Fever?
Generally speaking, the prognosis for individuals diagnosed with scarlet fever is excellent when properly treated. There are typically no long-term sequelae in uncomplicated cases of scarlet fever. Individuals will generally begin to improve after a few days. Historically, scarlet fever resulted in mortality rates of 15%-20%, however, with the advent of antibiotics, mortality rates are now less than 1%.
Rarely, several serious complications can occur as a result of scarlet fever and streptococcal infection. The potential complication may include the following:
Reviewed on 2/16/2022
Medically reviewed by Robert Cox, MD; American Board of Internal Medicine with subspecialty in Infectious Disease
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