What causes scarlet fever?
“Scarlet fever is caused by a bacteria called Group A streptococcus (group A strep),” explains Dr Colin Brown.
The bacteria is very contagious and spreads from person to person very easily. You can catch it by breathing in droplets when an infected person coughs or sneezes, or from touching surfaces that an infected person has touched. After becoming infected, it takes between two and five days to develop symptoms.
Diagnosis
A doctor can often diagnose scarlet fever simply by looking at the rash, throat and tongue. Sometimes they may also take a swab from the back of the throat in order to get a bacterial culture, and arrange a blood test. These will then be sent to the lab to confirm the diagnosis.
How is scarlet fever prevented?
The best way to prevent scarlet fever infections is to observe the good hygiene habits that we all adopted during the height of the Covid-19 pandemic. The most important step is to wash your hands regularly, particularly after coughing or sneezing, and before preparing food or eating. If this isn’t possible, using an alcohol-based hand sanitiser is the next best thing.
The following tips will also help to prevent infections:
- Cover your mouth and nose with a tissue when you cough or sneeze.
- Put used tissues in the bin.
- If you don’t have a tissue, cough or sneeze into your upper sleeve or elbow.
- Keep rooms well ventilated.
- Thoroughly wash glasses, utensils, and plates after someone who is sick uses them. These items are safe for others to use once washed.
There’s some evidence that there have been fewer group A strep infections in areas of the country where all children have been offered the live attenuated influenza vaccine (LAIV) via a nasal spray. This is available to children from the age of two, via a GP, or through the school vaccination service.
If you suspect that your child has scarlet fever, be aware that they can pass it on to someone else until 24 hours after their first dose of antibiotics. If they don’t take antibiotics, they could be contagious for two or three weeks after symptoms first start. It’s possible to get scarlet fever more than once, so having it doesn’t protect you from getting it again in the future.
How should you treat scarlet fever
“Scarlet fever is treated with antibiotics, typically a penicillin,” says Dr Amuthalingam. “It’s important to complete the full course of antibiotics as prescribed by a doctor. While mild cases may be managed at home with rest and supportive care, it’s essential to consult a healthcare professional for proper diagnosis and treatment, especially in severe or complicated cases.” He adds: “Early identification and treatment of streptococcal infections in household contacts can help prevent the spread of scarlet fever.”
While the antibiotics take effect, most symptoms can be managed by drinking cool fluids, eating soft foods if you have a sore throat and taking painkillers like paracetamol to bring down a high temperature. Calamine lotion and antihistamine tablets can also be helpful to relieve itching.
Complications of scarlet fever
Complications are rare, but they can happen during the height of the infection or for a few weeks afterward. These include ear infections, throat abscesses and sinusitis, along with more serious issues like pneumonia, meningitis and rheumatic fever. If left untreated, there’s also a risk that the bacteria which causes scarlet fever could spread to the heart, lungs and kidneys.
The most serious complication is sepsis, caused by invasive group A strep (iGAS). Thankfully this is very rare, especially in children. There have been 919 cases of iGas reported in the 2023/24 season, 116 of which were in 2024, but the majority of these were in older age groups – particularly those aged 75 and over.
According to Great Ormond Street Hospital, sometimes iGAS can cause scarlet fever, which is why it’s vital to seek treatment if you suspect your child has any of the telltale symptoms, and to stay vigilant for signs of complications.
“If a parent thinks their child is getting worse, for instance, if they are feeding or eating less than normal, are dehydrated, have a high temperature that won’t go down, are very hot and sweaty or seem more tired or irritable than normal, then contact your GP or call NHS 111,” advises Dr Brown. “An ambulance should be called if their child has difficulty breathing, will not wake up, has a spotty, purple or red rash anywhere on their body that does not fade when you press a glass against it, or has a seizure for the first time. Parents should trust their instincts and always seek help if they notice worrying behaviour in their child.”
Dr Amuthalingam adds: “Prompt diagnosis and treatment can help prevent these complications.”