There has been a rise in the number of scarlet fever cases reported across SE London, but what is it and how can you spot it?

Scarlet fever is a highly contagious disease that is most common in children under 10 years old.

Reasons for the escalation are unclear and identifying these continues to remain a public health priority, says The Lancet Journal.

In particular 2016 saw a huge rise in the number of reported cases, nearly 20,000 children were diagnosed which was the highest number on record since 1967.

The disease was a common cause of death in the Victorian era, but had largely been in decline since the introduction of antibiotics.

What is scarlet fever?

Scarlet fever is caused by bacteria known as group A streptococcus and is spread through close contact with people carrying the organism, often in the throat.

Symptoms include a sore throat, headache and fever, accompanied by a red rash that is rough to the touch.

What are the signs?

Early signs also include a pinkish/red sandpapery rash appearing within a day or two.

The rash usually first appears on the chest and stomach before spreading to other parts of the body. Scarlet fever is highly contagious and children aged two to eight are most at risk.

How is it treated?

The infection needs prompt treatment with antibiotics owing to the potential for complications and more severe illness caused by its group A strep bacteria.

How long does it last?

Symptoms of scarlet fever usually clear up in a week and most cases are uncomplicated as long as children finish the course of antibiotics.

Potential complications include ear infection, throat abscess and pneumonia. PHE said the parents of any child who does not show signs of improvement within a few days of starting treatment should seek urgent medical advice.

Long-term health problems from scarlet fever may include rheumatic fever, kidney disease or arthritis.

What should I do if my child has it?

Any child diagnosed with scarlet fever should not go to school until at least 24 hours after the start of antibiotic treatment while any adult affected should stay off work for at least 24 hours after starting treatment. There is currently no vaccine for scarlet fever.