Definition

Scarlet fever is a bacterial infection that produces a sore throat , upper respiratory symptoms, and a characteristic rash. It was once a serious childhood ailment, but it is quite treatable today with antibiotics.

Sore Throat Due to Inflammation

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Causes

Scarlet fever is caused by Group A beta-hemolytic Streptococcus pyogenes . This type of bacteria produces a toxin that causes a rash. Scarlet fever usually develops in conjunction with strep throat .

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition.

Risk factors include:

  • Age: 3-15 years old
  • Untreated strep infection
  • Close contact with someone who has an untreated strep infection
  • Overcrowded environments, or close proximity, such as a daycare facility, school, or home

Symptoms

The first signs of strep throat are:

  • A red, swollen throat
  • Fever above 101°F

If strep is diagnosed and treated with antibiotics, the infection may progress to scarlet fever.

Additional symptoms:

  • Vomiting
  • Headache
  • Swollen glands in the neck
  • White or yellow coating on the tongue
  • Bright red tongue ("strawberry tongue")
  • Loss of appetite
  • Abdominal pain
  • Body aches
  • Chills

Rash

Scarlet fever has a characteristic rash. Small red spots usually appear on the neck and chest within 24-48 hours after onset of the illness. This rash will spread quickly over the body to the abdomen, arms, and legs. The rash feels rough, like sand paper, and the redness blanches with pressure. There may also be flushing in the face with paleness around the mouth. Elbows, underarms, and other body crease areas may show red streaks called "Pastia's lines." In 7-10 days, the rash will peel off.

Diagnosis

The doctor will ask about your symptoms and medical history, and perform a physical exam. The doctor will swab the back of your throat for testing. The sample may be sent to a lab for a throat culture or a rapid strep antigen test ("rapid" strep test) may be done in the office.

Treatment

Scarlet fever can be treated with an antibiotic, such as penicillin or amoxicillin. It is usually taken for about 10 days. Erythromycin or azithromycin can be used for those with penicillin allergy. It is important to take all the prescribed medication to prevent recurrence or complications. People with an active strep infection are usually contagious until the antibiotic has been taken for at least 24 hours.

In rare cases, untreated strep throat infection may cause:

Prevention

Steps to prevent scarlet fever include:

  • Get early treatment for strep infections, including strep throat.
  • Do not return to school or work until you have taken your antibiotic at least 24 hours or your provider has given you approval.
  • Avoid contact with people who have untreated strep infections.
  • Do not share cups, utensils, towels, bed linen, or personal items with infected people.
  • Wash your hands often, especially after touching someone who may have an infection.
  • Several vaccines are currently under development.