Parents have been warned to look out for signs of scarlet fever as children prepare to go back to school next week.
Yesterday, Public Health England (PHE) reported a surge in the number of cases in the Gloucestershire, Avon and Wiltshire area over the last year.
England is split into 15 core areas, with Gloucestershire being grouped with nearby Avon and Wiltshire.
The health body had 147 reports of the disease between September 2012 and April 2013, but that figure has since risen to 557 in the same period in 2013/14.
That means cases have increased by nearly four fold over the last year.
Scarlet fever shows similar symptoms to chicken pox, but is rarer and have serious consequences, especially in children.
Once considered a serious infectious disease triggered by the streptococcus bacteria, it can now be treated through a course of antibiotics.
Dr Theresa Lamagni, PHE's head of streptococcal infection surveillance, said they hoped the Easter holidays would help with breaking the chains of transmission in school, but said they cannot rely on this being the case.