Scarlet fever is a bacterial illness that mainly affects children. It causes a distinctive pink-red rash.

The illness is caused by Streptococcus pyogenes bacteria, also known as group A streptococcus, which are found on the skin and in the throat.

Generally, scarlet fever is much less common than it used to be but in recent years there have been a number of significant outbreaks.

For example, figures published by Public Health England show that from September 2013 to March 2014 there were 2,830 cases of scarlet fever. For the same period in 2014/15 a total of 5,746 cases were recorded. The reason for recent increase is unclear.

It’s important to be aware of the signs and symptoms of scarlet fever so that early treatment with antibiotics can be given.

Scarlet fever symptoms

Scarlet fever usually follows a sore throat or a skin infection, such as impetigo, caused by particular strains of streptococcus bacteria.

Initial symptoms usually include a sore throat, headache and a high temperature (38.3C/101F or above), flushed cheeks and a swollen tongue.

A day or two later the characteristic pinkish rash appears. It usually occurs on the chest and stomach before spreading to other areas of the body, such as the ears and neck.

The symptoms of scarlet fever usually develop two to five days after infection, although the incubation period (the period between exposure to the infection and symptoms appearing) can be as short as one day or as long as seven days.

The rash feels like sandpaper to touch and it may be itchy. On darker skin the rash may be more difficult to see although its rough texture should be apparent.

When to seek medical advice

Scarlet fever usually clears up after about a week, but if you think you or your child may have it, see your GP for a proper diagnosis and appropriate treatment.

Your GP should be able to diagnose scarlet fever by examining the distinctive rash and asking about other symptoms. They may also decide to take a sample of saliva from the back of the throat so it can be tested in a laboratory to confirm the diagnosis.

There's no evidence to suggest that catching scarlet fever when pregnant will put your baby at risk. However, if you're heavily pregnant, tell the doctors and midwives in charge of your care if you've been in contact with someone who has scarlet fever.

How scarlet fever spreads

Scarlet fever is very contagious and can be caught by:

• breathing in bacteria in airborne droplets from an infected person's coughs and sneezes
• touching the skin of a person with a streptococcal skin infection, such as impetigo
• sharing contaminated towels, baths, clothes or bed linen

It can also be caught from carriers – people who have the bacteria in their throat or on their skin but don't have any symptoms.