Scarlet fever

Signs of scarlet fever

Scarlet fever is a disease caused by an infection with group A beta-hemolytic streptococcal bacteria that occurs in a small percentage of people with strep throat. The illness typically begins with a fever and sore throat. It may be accompanied by chills, vomiting, abdominal pain and malaise. The streptococcal bacteria produces a toxin that causes a rash that appears one to two days after the onset of illness. The rash initially appears on the neck and chest, then spreads over the body. While the rash is still red, the patient may develop Pastia’s lines, bright red coloration of the creases under the arm and in the groin.

Also known as: Scarlatina

Definition

Scarlet fever is a disease caused by infection with the group A Streptococcus bacteria (the same bacteria that causes strep throat).

Causes, incidence, and risk factors

Scarlet fever was once a very serious childhood disease, but now is easily treatable. It is caused by the streptococcal bacteria, which produce a toxin that leads to the hallmark red rash of the illness.

The main risk factor is infection with the bacteria that causes strep throat. A history of strep throat or scarlet fever in the community, neighborhood, or school may increase the risk of infection.

Symptoms

The time between becoming infected and having symptoms is short, generally 1 - 2 days. The illness typically begins with a fever and sore throat.

The rash usually first appears on the neck and chest, then spreads over the body. It is described as "sandpapery" in feel. The texture of the rash is more important than the appearance in confirming the diagnosis. The rash can last for more than a week. As the rash fades, peeling (desquamation) may occur around the fingertips, toes, and groin area.

Other symptoms include:

  • Abdominal pain
  • Bright red color in the creases of the underarm and groin (Pastia's lines)
  • Chills
  • Fever
  • General discomfort (malaise)
  • Headache
  • Muscle aches
  • Sore throat
  • Swollen, red tongue (strawberry tongue)
  • Vomiting

Signs and tests

  • Physical examination
  • Throat culture positive for group A strep
  • Rapid antigen detection (throat swab)

Treatment

Antibiotics are used to kill the bacteria that causes the throat infection. This is crucial to prevent rheumatic fever, a serious complication of strep throat and scarlet fever.

Expectations (prognosis)

With proper antibiotic treatment, the symptoms of scarlet fever should get better quickly. However, the rash can last for up to 2 - 3 weeks before it fully goes away.

Complications

Complications are rare with the right treatment, but can include:

Calling your health care provider

Call your health care provider if:

  • You develop symptoms of scarlet fever
  • Your symptoms do not go away 24 hours after beginning antibiotic treatment
  • You develop new symptoms

Prevention

Bacteria are spread by direct contact with infected people, or by droplets exhaled by an infected person. Avoid contact with infected people.

References

Bisno AL, Stevens DL. Streptococcus pyogenes. In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009:chap 198.

See also:

  • Symptoms

    Rashes

    Poison oak rash on the arm

    Rashes involve changes in the color or texture of your skin.

  • Disease

    Strep throat

    Throat anatomy

    Strep throat is caused by Group A Streptococcus bacteria. It is the most common bacterial infection of the throat.

Review date:
May 9, 2010
Reviewed by:
Linda Vorvick, MD, Seattle Site Coordinator, Lecturer, Pathophysiology, MEDEX Northwest Division of Physician Assistant Studies, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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