Scarlet fever

What is it?

Scarlet fever is an infection caused by Group A Streptococcus (andquot;strep") bacteria. It causes a finely textured rash that can appear like sandpaper along with other symptoms. It usually occurs after a strep infection of the throat (strep pharyngitis, or strep throat), but occasionally after a strep skin infection. The rash of scarlet fever is caused by a toxin that the strep bacteria produce.

Scarlet fever once was common among children ages 2 to 10, but now it is relatively rare. The reason for this remains a mystery, especially because there has been no decrease in the number of cases of strep throat or strep skin infections.

Symptoms

Scarlet fever usually is triggered by a strep throat infection, which causes the following symptoms:

• fever and chills
• headache
• a red and sore throat
• enlarged tonsils
• swollen lymph nodes (andquot;swollen glands") in the neck.

Within 12 to 48 hours after these symptoms appear, the typical scarlet fever rash begins.

The scarlet fever rash is as bright red as sunburn, and it often has a fine texture like sandpaper (andquot;sandpaper rash") or gooseflesh (goosebumps). It usually starts in the underarm area, groin and neck, then spreads to the trunk, back, arms and legs. Other symptoms of scarlet fever include:

• a pale area around the mouth
• white strawberry tongue—A white coating with red dots on the tongue's surface
• red strawberry tongue or raspberry tongue that occurs when the white tongue coating peels and leaves a red coating with red dots
• pastia's lines—A darkening or redness of the normal skin creases, especially in the crook of the arm.

Occasionally, scarlet fever follows a streptococcal skin infection, such as an infection of burns or wounds, or impetigo. When this happens, the rash and related skin symptoms appear, but there are no symptoms related to strep throat.

Diagnosis

Your doctor will suspect scarlet fever based on the appearance of your rash and its timing in relation to other symptoms. During the physical examination, your doctor will check for the symptoms of scarlet fever. To confirm the diagnosis of a strep infection, your doctor will take a swab of throat secretions. If no sore throat is present, then the exam will focus on other possible sources of strep infection, such as impetigo.

Expected duration

Although the scarlet fever rash generally fades after 6 to 7 days, it is followed by a period of skin flaking and peeling that lasts for 10 to 14 days. Occasionally, in patients with severe rash, peeling and flaking may persist for a few weeks.

Prevention

The best prevention is thorough hand washing, especially by those who have a sore throat or other symptoms of strep infection. If you live with someone who has a strep infection, and you develop a sore throat or fever, make an appointment with a health care professional.

Treatment

Scarlet fever is treated with antibiotics, usually penicillin or azithromycin. However, other antibiotics may be effective as well.

In addition to antibiotic treatment, patients with scarlet fever and severe throat symptoms may try:

• acetaminophen (Tylenol) or ibuprofen (Advil, Motrin and others) to relieve pain and reduce fever
• soothing gargles to fight sore throat (in adults and older children who can gargle safely)
• a cool-mist humidifier to soothe the breathing passages and throat
• a liquid diet, including warm soups or cold milkshakes, if the patient's sore throat makes it difficult to swallow solid foods.

When to call a professional

Call your doctor promptly whenever you or someone in your family develops a rash that is accompanied by fever or other symptoms of infection.

Prognosis

In most cases, all signs of the scarlet fever rash are gone within two weeks, and there is no long-term scarring. However, because scarlet fever is a strep infection, patients with this illness have the same risk of strep complications (otitis media, pneumonia, rheumatic fever, glomerulonephritis, etc.) as patients without a rash.

Additional info

Centers for Disease Control and Prevention (CDC)
https://www.cdc.gov/