Health Encyclopedia

Scarlet fever

Definition

Scarlet fever is caused by an infection with bacteria called group A streptococcus. This is the same bacteria that cause strep throat.

Alternative Names

Scarlatina; Strep infection - scarlet fever; Streptococcus - scarlet fever

Causes

Scarlet fever was once a very serious childhood disease, but now it is easy to treat. The streptococcal bacteria that cause it produce a toxin that leads to the red rash the illness is named for.

The main risk factor for getting scarlet fever is infection with the bacteria that cause strep throat. An outbreak of strep throat or scarlet fever in the community, neighborhood, or school may increase the risk of infection.

Symptoms

The time between infection and symptoms is short, most often 1 to 2 days. The illness will likely begin with a fever and sore throat.

The rash first appears on the neck and chest, then spreads over the body. People say it feels like sandpaper. The texture of the rash is more important than the appearance to confirm the diagnosis. The rash can last for more than a week. As the rash fades, the skin around the fingertips, toes, and groin area may peel.

Other symptoms include:

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

Exams and Tests

Your health care provider may check for scarlet fever by doing a:

Physical examination
Throat culture that shows bacteria from group A streptococcus
Throat swab to do a test called rapid antigen detection

Treatment

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

Outlook (Prognosis)

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

Possible Complications

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

Acute rheumatic fever, which can affect the heart, joints, skin, and brain
Ear infection
Kidney damage
Liver damage
Pneumonia
Sinus infection
Swollen lymph glands or abscess

When to Contact a Medical Professional

Contact your 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 an infected person coughs or exhales. Avoid contact with infected people.

References

Bryant AE, Stevens DL. Streptococcus pyogenes. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 197.

Michaels MG, Williams JV. Infectious diseases. In: Zitelli BJ, McIntire SC, Nowalk AJ, Garrison J, eds. Zitelli and Davis' Atlas of Pediatric Physical Diagnosis. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 13.

Shulman ST, Reuter CH. Group A streptococcus. In: Kliegman RM, St Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 210.

Stevens DL, Bryant AE, Hagman MM. Nonpneumococcal streptococcal infections and rheumatic fever. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 274.

Review Date:1/29/2022
Reviewed By:Linda J. Vorvick, MD, Clinical Associate Professor, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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