Scarlet fever: a doctor's advice

When is a fever or sore throat more than that? When does it become scarlet fever? A couple of months ago our 3-year-old developed a fever, promptly vomited and then felt better. This is our third child, so we are well-versed in how to manage constant fevers, runny noses, and being sick - so we put it down to a bug. A day later, he was off his food and had quite a high temperature. Looking into his mouth, I saw signs of scarlet fever. He had also developed a rash - another clue to the diagnosis.

As a GP, I knew the signs, so I rang 111, and a couple of hours later I had a prescription for antibiotics. Within 48 hours he was a lot better and starting to eat more. We later heard that there were a few children in his nursery that had been treated for scarlet fever.

What is scarlet fever?

Bacteria called Group A streptococcus (GAS) can cause a number of different infections such as impetigo, cellulitis, and strep A throat (bacterial tonsillitis) These bacteria can also cause scarlet fever. This infection usually affects children under 10 but can infect adults too - It is very infectious.

Scarlet fever has been around for centuries and every few years, we see a rise in cases. It was the main cause of death in children under 10 in the 1800s, due to people living in overcrowded houses. Now, as people are more spread out, the infection tends to be more contained so there are fewer deaths.

During previous scarlet fever outbreaks, there have been new strains of Group A streptococcus, but this does not seem to be the case in 2022. The rise in cases has been put down to more social mixing - less masks and no social distancing.

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Why has there been a scarlet fever alert?

In the UK there are normally a few cases of scarlet fever every year - these tend to be in children and usually come with mild symptoms. Every few years, there is usually a period that is particularly worse than others. The last outbreak was in 2017-2018 when the highest number of cases since 1960 were recorded. There have been more cases in 2022 than were seen during this same time period in 2021 indicating an outbreak. More importantly, we have seen increased cases of unwell children with pneumonia or invasive Group A streptococcus - causing more widespread infection.

When Group A streptococcus goes into the blood stream or anywhere else it shouldn't, such as in the muscles or the lungs, it can make people very unwell and can lead to death. This is what's known as invasive Group A strep (iGAS). Invasive Group A streptococcus is quite rare, but in 2022 there has been four times as many cases as there were during the 2017 surge. As of 4th December 2022, there have been six deaths in children under 10, compared to four during the same period in 2017.

What are the symptoms of strep A?

The classic symptoms of Group A strep throat are those of tonsillitis - the Centor criteria - are used by GPs to consider when someone may need antibiotics. Two or more of these symptoms usually means that a sore throat is likely to be caused by Group A streptococcus. This criteria is hard to use in children as children often have various symptoms that may not fit. In these cases we do a thorough examination to see how likely their symptoms are due to strep A.

Strep A symptoms

• Sore throat.
• Fever - temperatures are usually over 38°C.
• No cough.
• White spots on the tonsils.
• Painful, swollen neck lymph nodes.

It is often very difficult to predict when Group A strep throat can become scarlet fever.

How to tell if it's scarlet fever

My son had a sore throat with red and white spots on his tonsils first, and then I noticed he had a 'strawberry tongue' - a red tongue covered in white spots. On his tummy, he had developed a red, bumpy rash that felt like sandpaper.

Strawberry tongue

In people with darker skin, the rash is often difficult to see so doctors usually go by feel. This rash can spread throughout the body and can make the skin peel.

In most cases, antibiotics will make patients better. All that's needed to prevent spreading Group A streptococcus is to stay clear of others while you have the symptoms, and for 24 hours after you start antibiotics. The rash can last for up to seven days and often children can feel quite tired during the whole episode.

You can go back to school or work once you have been on antibiotics for 24 hours and you no longer have a fever.

When should we worry?

What are the complications of scarlet fever?

As well as the increase in children with complications from scarlet fever, there has also been an increase in pneumonia and invasive Group A streptococcus, as mentioned earlier. Both can cause serious illness.

Practical tips for managing a sore throat

• Ice lollies - they provide energy and fluids. They are also soothing when you have a burning throat.
• Water - drink often and take sips - try not to glug down too much at once as this can make you feel sick.
• Food - just eat what you can and want to eat, same goes for kids. Even if, like in my child’s case, it is just yogurt and white chocolate buttons. They can catch up on nutrition when they feel better.
• Take paracetamol and ibuprofen as they need it for fever and pain. Look at the packet for recommended doses and never give more than this.

As a parent, it can be hard to work out when to worry and call for help. I often tell my patients that you know your child the best, so if you are concerned, call your doctor.

Scarlet fever is still not common - and more often than not your child will have a sore throat from a virus, or it could be strep throat - in which case your child may need antibiotics. The scarlet fever alert is really there to let GPs and parents know to explore further if confronted with a fever and sore throat, and to then act quickly when there may be a chance it could be scarlet fever or iGAS.