Scarlet Fever Surging in the U.K.: Should Parents Be Worried?

In early December 2022, the United Kingdom Security Agency issued a warning about the rise of scarlet fever cases. The relatively common infection can sometimes cause serious complications, including death.

From mid-September to early December, the country documented 6,601 cases of scarlet fever, which is a substantial increase from 2,538 cases in the same time period during the last regional surge from 2017 to 2018.

Scarlet fever can sometimes progress into a more serious illness called invasive group A strep (iGAS). In the U.K., cases of iGAS have been high this season as well and have resulted in 60 deaths, 13 of which were children under 18.

Here in the United States, the Centers for Disease Control and Prevention (CDC) issued a health advisory on December 22, 2022 about an increase in pediatric iGAS infections. The CDC says the goal of issuing the advisory is to let healthcare providers and public health officials know about the recent increase. But the CDC does say the overall number of cases is relatively low and iGAS cases are rare in children.

With all of the germs circulating, it's understandable for parents to be concerned about yet another illness. You may also be wondering whether what's happening in the U.K. could happen here.

What Causes Scarlet Fever?

Scarlet fever is an infection caused by group A streptococcus, or strep throat. The illness is fairly common in the United States with symptoms that include red rashes, red lines, flushed faces, and "strawberry tongues," ones that appear red and bumpy.

Though usually easily treated with antibiotics like amoxicillin and penicillin, scarlet fever can sometimes cause complications like abscesses or collections of pus.

“They usually occur in the neck or in the lymph nodes/glands of the neck,” explains Zachary Hoy, MD, a pediatric infectious disease specialist at Pediatrix Nashville. “There can also be post-infectious complications, such as kidney issues, or more invasive infections, such as bone/joint infections that require intravenous (IV) antibiotics and hospitalization.”

If a scarlet fever infection progresses, it can result in bloodstream bacterial infections, meningitis, low blood pressure, and multi-organ failure.

How Dangerous is Scarlet Fever?

Scarlet fever itself is not very dangerous and is usually easily treated with a round of common antibiotics. As a vulnerable population, children are at a higher risk of more serious complications from the infection.

“The main concern about scarlet fever is that affected persons can predispose people to acute rheumatic fever,” says Anthony Hudson, MD, a pediatrician at Children’s Hospital New Orleans.  “Acute rheumatic fever can cause more severe disease affecting the heart and brain.”

If a child is allergic to penicillin, they are at an even greater risk for harmful outcomes of scarlet fever as doctors have to seek potentially less effective antibiotics like clindamycin.

What's Behind the Surge in the U.K.?

There are many different theories behind the current scarlet fever surge in the U.K. Dr. Hudson suggests the increase in cases is a common occurrence with the disease. 

“Not all strains for the strep bacteria produce the toxin,” Dr. Hudson says. “These toxin-producing strains appear to come and go. We have seen very little of it for years. The increase in cases in the U.K. suggests that these toxin-producing strains are starting to circulate again there. With so much global travel, I suspect that they will appear in the U.S. in the not-too-distant future.”

Others, like Dr. Hoy, cite the illness’ possible genetic mutations allowing it to make toxins that increase spread and severity. 

“Sometimes strep can occur as a secondary infection after a respiratory viral illness," Dr. Hoy says. "We have seen an increase in respiratory viral infections at this time of year, including influenza and respiratory syncytial virus (RSV), so that may make patients more susceptible to bacterial infection with strep.”

A rise in scarlet fever has also recently been seen in China but even there it’s not clear why. Oladele A. Ogunseitan, PhD, a professor of population health & disease prevention, UCI Program in Public Health says it could possibly be due to the return to crowded spaces post-COVID lockdown, as with many other airborne infections.

Should U.S. Parents Be Worried About Scarlet Fever?

Many experts speculate the U.K. scarlet fever outbreak could soon migrate to the United States if it hasn't already. While parents shouldn’t worry too much, they should take precautions to keep themselves and their children safe. Luckily, many of the tips for preventing scarlet fever are similar to what you are probably already doing to prevent other infections, like COVID-19. 

“One of the best prevention strategies is hand washing and avoiding others who are sick,” Dr. Hoy advises. “Also, do not share drinks with others because strep infection can be spread via contact with respiratory droplets.”

Parents should also be aware of concerning symptoms and have them addressed in order to get treatment early. Seeing a doctor within 24 hours of symptoms is best.

“If children have a severe sore throat, they should be evaluated by their pediatrician and tested for strep even if they don’t have a rash,” says Dr. Hudson. “If positive, they should receive antibiotics and take the entire course prescribed by their doctor.”

Once given antibiotics, parents should still keep their children home for at least 24 hours. Strep is typically less transmissible 12 hours after starting antibiotics but children should still be kept home from school or daycare until fever free.

Overall, it's best for parents to be aware of and treat early symptoms, follow through with treatment plans and alert your child's healthcare provider if symptoms worsen or more symptoms develop.