Scarlet fever - Diagnosis 

Your GP can usually diagnose scarlet fever by looking at the characteristic rash and other symptoms.

To confirm the diagnosis, a sample of saliva is taken from the back of the throat, known as a throat swab, and tested in a laboratory. This reveals which bacteria have caused the infection. A blood test is sometimes required.

Scarlet fever is a notifiable disease. This means that doctors must report any cases to the local health protection unit so they can monitor the spread of disease.