These bacteria are commonly found on the skin or in the throat where they can live without causing disease. Under particular circumstances, however, these bacteria can cause disease. Scarlet fever is an illness characterised by a rash which usually accompanies a sore throat, with the rash being caused by the bacteria releasing specific toxins into the bloodstream. Scarlet fever is a 'notifiable' disease which means that doctors in England and Wales have a legal obligation to inform the 'Proper Officer' of the Local Authority of suspected cases.