A new study says England is seeing a "dramatic increase" in cases of scarlet fever - an infectious disease that mostly affects children. So how do you get it, what are the symptoms, and how is it treated?
Cases of scarlet fever had been declining for decades until a "dramatic increase" was spotted in England in 2014. Now researchers writing in The Lancet say England is experiencing an "unprecedented rise in scarlet fever with the highest incidence for nearly 50 years."
But they say the reasons for the escalation are unclear and that identifying the cause "remains a public health priority."
Their findings are based on a survey of notifications of scarlet fever from January 1, 1911 to December 31, 2016, in England and Wales.
"Population rates of scarlet fever increased by a factor of three between 2013 and 2014," write the researchers. That saw the rates of infection go from 8.2 to 27.2 per 100,000 people.
Further increases were observed in 2015, when the rate was 30.6 per 100,000, and then again in 2016 (33.2 per 100,000).
At a total of 19,206 in 2016, it was "the highest number of cases and rate of scarlet fever notification since 1967.
So what is scarlet fever?
Scarlet fever, or scarlatina, is a bacterial infection. Specifically, it's a "group A streptococcal," infectious disease, which usually occurs in childhood and most commonly in winter and spring.
Scarlet fever is a group A streptoccus infectious diseases. It spreads easily among crowds of people
In England, the median age of cases in 2014 was 4 years, "with an incidence of 186 per 100,000 children" under the age of ten, say the researchers in The Lancet. Though adults do also get it.
The US Centers for Disease Control and Prevention says a group A Strep can cause a range of infections "from minor illnesses to very serious and deadly diseases."
Most cases of scarlet fever are mild, according to Key Facts provided by the World Health Organization, "however complications can develop, including acute rheumatic fever and/or acute kidney disease."
What are the symptoms?
The WHO lists the following symptoms: high fever, a sore throat or a skin infection and a rash around the neck, underarm or groin, which spreads around the body. After about 2-7 days of the rash, the skin slowly peels off. The rash can feel like sandpaper.
Symptoms also include a whitish coating on the tongue early in the illness, or what the CDC describes as a "strawberry (red and bumpy)" tongue, and swollen glands in the neck.
"Scarlet fever usually occurs following infection with group A streptococcus in the throat or on the skin," continue the WHO's Key Facts. "Only about 10 percent of the group A streptococcus that cause disease produce the toxin, or poison, that causes scarlet fever."
But the CDC says cases can also occur "along with strep throat," a throat infection caused by group A Strep.
The incubation period - the time from the infection to the first symptoms appearing - is between two and six days.
You, or you child, may also experience headache or body aches, nausea, vomiting or abdominal pain.
It's quite a range of often quite common symptoms, so check with a doctor if you are unsure.
How is scarlet fever transmitted?
Scarlet fever is spread from person to person through "respiratory droplets or through direct contact with mucus, saliva or the skin of infected people," advises the WHO.
Respiratory droplets are water-based but potentially dried-out residuals, caused when humans breathe, talk, sneeze or cough, and they contain infectious pathogens.
As with most infectious diseases, scarlet fever spreads quickly where there is close contact with other people in crowded situations and in large groups, such as households, public transport, daycare centers and schools.
So avoid direct contact with people who are known to have scarlet fever.
Most cases of scarlet fever are mild, but strepotoccus bacteria can be deadly, as seen in this illustration from 1880
And wash your hands regularly and properly, especially after coughing or sneezing and before preparing or eating food. It is the best way to lower the risk of getting scarlet fever, or spreading it.
Children between the ages of 5 and 15 years are most at risk.
How is scarlet fever treated?
The most common treatment remains antibiotics, such as penicillin or amoxicillin for people who are not allergic to penicillin. There are other antibiotics for people allergic to penicillin.
While there is a growing resistance to antibiotics, the CDC says "antibiotics help shorten how long someone is sick, prevent spreading the disease to others, and prevent getting complications like rheumatic fever."
If you are taking antibiotics for scarlet fever, and have done so properly for 24 hours or longer, the CDC says you will usually no longer be infectious for other people.
But always check with a health professional for the best advice for your specific condition.
*The main image in this article depicts the difference between scarlet fever (on the left) and measles (on the right)