Scarlet fever is caused by an infection with bacteria called A streptococcus. This is the same bacteria that cause strep throat.
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.
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
- General discomfort (malaise)
- Muscle aches
- Sore throat
- Swollen, red tongue (strawberry tongue)
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
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.
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.
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
- Sinus infection
- Swollen lymph glands or abscess
When to Contact a Medical Professional
Call 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
Bacteria are spread by direct contact with infected people, or by droplets an infected person coughs or exhales. Avoid contact with infected people.
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. 8th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 199.
Shulman ST. Group A Streptococcus. In: Kliegman RM, Stanton BF, St. Geme JW, Schor NF, eds. Nelson Textbook of Pediatrics. 20th ed. Philadelphia, PA: Elsevier; 2016:chap 183.