Public Health England has reported a dramatic increase in the number of reported cases of Scarlet Fever in England and Wales in the past three years. About 17,500 cases were reported in the 2014 season, compared to less than 5,000 in 2013 and less than 2,000 for many years before that. The current rate is about 600 reported cases per week. Incidence rates have not been this high since the 1960’s. Researchers have not been able to determine the cause of the re-emergence of this Victorian-era disease.
What is Scarlet Fever?
Scarlet Fever is a streptococcal disease, like strep throat and impetigo. Group A streptococci bacteria are normally found in the nose and throat. Most streptococci excrete enzymes and toxins that break down red blood cells. The poisonous toxins produced by Group A streptococci cause of the red rash of Scarlet Fever.
Scarlet Fever (or ‘Scarlatina’) was a very serious infection in the Victorian era, killing 15-20% of those affected by the disease. Better living conditions, improved diagnostic tools, the natural evolution of the bacterium and better medicines are all credited with improving the prognosis of patients diagnosed with Scarlet Fever. Most cases will clear up within one week of starting the course of antibiotics with no long-term effects.
The initial symptoms of Scarlet Fever will begin within 1-4 days of exposure to the bacteria. The rash will appear 1-4 days after the onset of illness. Symptoms include:
- sore, very red throat
- whitish coating on the surface of the tongue
- fever of 38°C (101°F)
- swollen glands in the neck
- red, rough rash, starting on chest or stomach, then spreading
Potential complications include ear infection, throat abscess and pneumonia. Untreated Scarlet Fever can cause severe complications, including rheumatic fever, sepsis, necrotising fasciitis, toxic shock syndrome and kidney disease.
Scarlet Fever is extremely contagious, with the highest incidence rates during the winter and spring. Transmission is usually via airborne droplets projected through coughing and sneezing. The organism is able to survive on surfaces, meaning that someone can touch a contaminated surface (door handle, railing, counter) and contract the infection by then touching his eyes, nose or mouth.
Although older children and adults can be infected, Scarlet Fever is typically a childhood disease, most prevalent in 1-10 year olds. Over time, a person will develop immunity to the most prevalent Group A streptococci serotypes.
A confirmed diagnosis of Scarlet Fever must be made before treatment can be administered. The physician will look for outward evidence of Scarlet Fever (red throat, rash, white tongue, fever), then confirm the suspicion with a rapid strep test or throat culture.
Once confirmed, penicillin will be prescribed unless the patient has an allergy to penicillin, in which case erythromycin will be prescribed.
There is no vaccine for Scarlet Fever, so the best method for prevention is to practice good hand hygiene. Children should be taught to wash their hands frequently, especially before eating and after sharing toys with friends.
Those affected by Scarlet Fever are most contagious in the acute stages of the illness and should avoid contact with others until 24 hours after first dose of antibiotics.
Why the Sudden Increase in Scarlet Fever Cases?
Health officials in the United Kingdom are still trying to answer this question. After testing of more than 400 isolates of the disease, a new strain of Scarlet Fever has been ruled out. Likewise, there is nothing to support a theory that the bacteria have developed an increased resistance to antibiotics. Dr. Theresa Lamagni of Public Health England has suggested that the re-emergence of the disease may reflect the long-term natural cycle in disease incidence, as is seen in many types of infection.
A dramatic increase in cases was also observed in Hong Kong and mainland China, starting in 2011. A 2015 study that used genome sequencing techniques to investigate those outbreaks (Scientific Reports) did indicate increasing levels of resistance to some antibiotics (including erythromycin), although no resistance to penicillin was detected. The authors also suggested that environmental factors, such as temperature and rainfall, bacterial determinants and the immune status of the patient may all play a significant role in the latest outbreaks.
Whatever the cause of the increased incidence rates, the Scarlet Fever currently affecting England and Wales remains a mild childhood illness that is easy to both diagnose and treat. Continued reporting, analysis and tracking will help researchers and public health officials determine the long-term effect and trajectory of the disease.
- Ben Zakour, Nouri L. et al. (2015). Transfer of scarlet fever-associated elements into the group A Streptococcus M1T1 clone.Scientific Reports. Accessed March 29, 2016: DOI: 10.1038/srep15877
2. Centers for Disease Control and Prevention (2016, January). Scarlet Fever: A Group A Streptococcal Infection. Accessed March 29, 2016: http://www.cdc.gov/features/scarletfever/
3. Public Health Agency of Canada (2011, September). Scarlet Fever Fact Sheet. Accessed March 29, 2016: http://www.phac-aspc.gc.ca/id-mi/scarl-eng.php
4. Sotoodian, Bahman and James, William D (2016, March 7). Scarlet Fever. Accessed March 29, 2016: http://emedicine.medscape.com/article/1053253-overview#a4