Scarlet fever

Scarlet fever is a rash caused by toxins which are made by Group A streptococcus bacteria. This is the same bacteria that causes strep throat. If you're sensitive to these toxins and you get a streptococcal throat or skin infection they give you a whole-body rash.

If you’re not sensitive to the toxins you can still get a streptococcal infection, but you won’t get the scarlet fever rash.

Most children have developed antibodies to the toxin by the age of 10, and the antibody is passed on in breast milk. For this reason, most scarlet fever happens in children 4 to 8 years of age. It used to be very common, but it’s not often seen anymore.

How streptococcal bacteria are spread

• By breathing in air droplets coughed or sneezed by a person with a streptococcal infection.
• By directly touching the skin of someone who has a skin infection, or someone who has the bacteria on their skin without knowing it. Up to 1 in 5 school children may carry streptococcal bacteria on their skin.
• By touching contaminated surfaces, hands or objects (such as towels, sheets, cups, plates, and eating utensils) used by an infected person.

Symptoms usually start 1 to 4 days after contact with the bacteria.

• The illness usually begins quickly with fever and a sore throat.
• You may have tender lumps in your neck – these are lymph nodes.
• There may also be vomiting (being sick) and tummy pain.
• You may get muscle aches, lose your appetite and feel unwell.
• The rash usually starts 1 to 2 days after the illness begins.
• The rash starts on your neck, underarms and groin, then spread over your body. It usually starts as small, flat, red blotches that gradually become small bumps with a rough surface. This sandpapery feel helps tell the difference between scarlet fever and other rashes.
• A child often gets a pink or red face, with a pale area around their mouth.
• Your tongue may get a white coating with red spots, often called 'strawberry tongue'. Once this coating comes off your tongue is bright red.
• The scarlet fever rash usually fades in 7 days.
• There is usually some skin peeling as the rash fades. This can last 6 weeks.

Image credit: DermNet NZ

Your healthcare provider will ask you questions and do a physical examination. Scarlet fever can be diagnosed through:

• the typical history and appearance
• a throat swab to test for the presence of Streptococcus bacteria.
• a rapid antigen test (in some clinics only)
• blood test to test for Streptococcus antibodies.

See your doctor or nurse practitioner if you think you or your child may have scarlet fever. Early treatment can prevent complications.  

Scarlet fever is treated with antibiotics, usually penicillin for 10 days. You’ll need to rest and drink plenty of water. You can use paracetamol and ibuprofen for throat pain and fever if they are safe for you to use. Your pharmacy has over-the-counter sprays, gargles and lozenges for throat pain.

You should isolate yourself in 1 room to try and protect other people in your home. Careful handwashing is important for preventing the spread. Wash your hands thoroughly with soap. Avoid sharing towels, eating utensils such as spoons, forks, knives, plates and cups or other personal items.

You should stay home from school, preschool or work for at least 24 hours after starting antibiotics or when you are feeling better if you have not taken antibiotics.

There is no vaccine available to prevent scarlet fever.

Scarlet fever is usually mild. However, streptococcal infections can cause serious complications such as rheumatic fever and kidney problems. Read more about rheumatic fever in children.