The number of cases of the highly-contagious scarlet fever have soared to a 24-year-high, figures show.
Health officials said that t here have been "widespread" increases in the number of cases in England.
During February there were significantly more cases of the bacterial illness than would normally be expected for this time of year, according to Public Health England (PHE).
In the four weeks to February 23, health officials were notified of 868 cases of scarlet fever - over the last four years experts have noted an average of 444 cases.
Officials said that the figure is at its highest for this time of year since 1990.
The increase has been noted across England apart from in the north west.
An interim report on the infection states: "Routine monitoring of surveillance data has identified widespread increases in scarlet fever notifications in February 2014, beyond those seasonally expected. These are the highest notification totals for this time of year since 1990."
A PHE spokeswoman said that there are seasonal rises in scarlet fever between December and April each year.
Every few years there is also a notable increase in the number of cases and the latest bout of infections is likely to be part of that cycle, she added.
The organisation has warned health officials to be "mindful" of the current rise in figures when treating patients.
The most noticeable symptom of scarlet fever is a distinctive pink-red rash that feels like sandpaper to touch. Other symptoms include a high temperature, a flushed face and a red, swollen tongue.
It is "extremely contaigous" and can be caught by breathing in bacteria from an infected person's coughs and sneezes, touching the skin of a person with a streptococcal skin infection and sharing contaminated towels, baths, clothes or bed linen.
PHE's head of streptococcal infection surveillance Dr Theresa Lamagni 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. Symptoms usually clear up after a week and in the majority of cases remain reasonably mild providing a course of antibiotics is completed to reduce the risk of complications.
"Children or adults diagnosed with scarlet fever are advised to stay at home until at least 24 hours after the start of antibiotic treatment to avoid passing on the infection.
"We will continue to closely monitor these increases and work with healthcare professionals to try and halt the spread of infection."