Definition | Causes | Risk Factors | Symptoms | Diagnosis | Treatment | Prevention

Definition

Scarlet fever is an infection caused by a type of bacteria. This bacterial infection produces a sore throat, fever, and a specific rash. The bacterial infection is very treatable 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:

  • 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 symptoms of scarlet fever are usually sore throat and fever.

Scarlet fever has a specific rash. Small red spots usually appear on the neck and chest within 24-48 hours after the illness starts. This rash will spread quickly to the abdomen, arms, and legs. The rash feels rough, like sand paper. If you press down on the red areas, they will turn pale under the pressure. There may also be flushing in the face with paleness around the mouth. Elbows, underarms, and other body crease areas may have red streaks called "Pastia's lines." The rash then fades. The skin peels for as long as several weeks.

Additional symptoms can include:

Diagnosis

Your doctor will ask about your symptoms and medical history. A physical exam will be done. The back of your throat will be swabbed for testing. The sample may be sent to a lab for a throat culture. A rapid strep antigen test ("rapid" strep test) may be done in the office. Your doctor will make the diagnosis if you have the scarlet fever bacterial infection and rash.

Treatment

The infection that causes scarlet fever can be treated with an antibiotic. It is important to take all the prescribed medication. Doing so will prevent scarlet fever from returning, and also prevent 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:

  • Getting early treatment for strep infections, including strep throat
  • Avoiding contact with people who have untreated strep infections
  • Washing your hands frequently