More than 3,500 cases of scarlet fever – the vast majority in children – have been reported since September in a “significant” rise, health officials have said.
Some 3,548 new cases have been recorded in England - more than double the normal average for the season, according to data from Public Health England (PHE).
Over the previous decade, around 1,420 cases were reported in the same period each year.
“The last season to have this level of scarlet fever activity was 1989/1990 when 4,042 notifications were received,” PHE said. Most of the new cases (95 per cent) were in under-18s.
Scarlet fever is a highly contagious bacterial illness that causes a distinctive pink-red rash which feels like sandpaper to touch.
It can be itchy and start in one area, but soon spreads to many parts of the body, such as the ears, neck and chest.
Other symptoms include a high temperature, vomiting, a flushed face and a red, swollen tongue.
Scarlet fever usually follows a sore throat or skin infection and is most common between the ages of two and eight.
It is caught by breathing in bacteria in airborne droplets from an infected person’s coughs and sneezes, or through touching their skin.
Sharing contaminated towels, baths, clothes, bedding, cups and utensils can also pass on the infection.
It is treated by antibiotics which must be taken for 10 days, even though most people recover after four to five days.
Dr Theresa Lamagni, PHE’s head of streptococcal infection surveillance, said: “The first symptoms of scarlet fever often include a sore throat, headache, fever, nausea, and vomiting.
“Between 12 to 48 hours after this, a characteristic rash develops. Cases are more common in children, although adults can also develop scarlet fever.”