The number of cases of highly contagious scarlet fever has hit a 24-year peak, according to new figures.
Health officials were notified of 868 cases of the bacterial illness in the four weeks to February 23 compared with an average of 444 cases over the last four years.
Public Health England (PHE) said the increase had been recorded in most parts of England apart from the North West.
A report into scarlet fever outbreaks said: "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 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.
Symptoms of the illness including a distinctive pink-red rash that feels like sandpaper to the touch, a high temperature, a flushed face and a red, swollen tongue.
Scarlet fever can be caught by breathing in bacteria from an infected person's coughs and sneezes, touching the skin of someone with a streptococcal skin infection, or sharing contaminated clothing or towels.
Dr Theresa Lamagni, head of streptococcal infection surveillance at PHE, 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."
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