Scarlet fever cases have rocketed nationwide with a reported 11,981 cases in the past 24 weeks.
Compared to the same period for the past five years this is an average 4,480 more.
Doctors are now urging parents to recognise the symptoms, particularly if their child has them, and to consult their GP straight away.
The majority of cases, 89 per cent, have been reported in under-10s.
While Scarlet fever is not usually serious and can be treated with antibiotics from your GP.
But complications that can arise include rheumatic fever and kidney problems. In rare cases death can occur.
Symptoms of scarlet fever develop within a week of being infected.
According to the NHS, early signs include a sore throat, a headache, a high temperature (38.3C or above), swollen glands in the neck and being sick.
This can then be followed by a rash on the body, a red face and a white or red tongue.
Dr Theresa Lamagni, of Public Health England, said: “Whilst current rates are nowhere near those seen in the early 1900s, the magnitude of the recent upsurge is greater than any documented in the last century.”
Once you’ve had scarlet fever, you’re unlikely to get it again.
What do the rash ad red face look like?
The rash usually starts on the chest or tummy, before spreading to other areas, it is made up of pink-red blotches that may join up, feels like sandpaper (this may be the most obvious sign in someone with dark skin), and may be brighter red in body folds, such as the armpits or elbows. It also turns white if you press a glass on it.
The rash doesn’t usually spread to the face, but the cheeks may turn very red. This may look a bit like sunburn, and the area around the mouth usually stays pale.
What does the white or red tongue look like?