Condition Basics

What is scarlet fever?

Scarlet fever is an infection that can happen with strep throat. The illness is named for its scarlet-coloured rash. Scarlet fever is most common in children and teens, but it can affect people of any age.

What causes it?

Scarlet fever is caused by streptococcal (strep) bacteria, the same bacteria that cause strep throat. There are many different strains of strep bacteria, some of which cause more serious illness than others. The type of strep that infects the throat and causes scarlet fever is called group A strep.

What are the symptoms?

Scarlet fever causes a rough, red rash along with symptoms of strep throat. These may include:

• A fever.
• A sore throat and pain when swallowing.
• A red, swollen throat or tonsils.
• White spots or coating on the throat and tonsils.
• Bright red spots on the tongue ("strawberry tongue").
• Swollen lymph nodes in the neck.

The rash usually appears one or two days after the fever starts. The rash starts on the neck, underarm, and groin area and then spreads to the rest of the body. The rash usually fades in about a week. Then the skin may start to peel.

Other symptoms that may appear before the rash include general body aches, headache, stomach ache, nausea, vomiting, or listlessness. These symptoms are more common in children than in adults.

How is scarlet fever treated?

Scarlet fever is treated with antibiotics. Treatment can prevent serious problems. If it's not treated, scarlet fever can lead to problems such as middle ear infection, sinusitis, and pneumonia. In rare cases, it can lead to rheumatic fever.

How is it diagnosed?

Diagnosis of scarlet fever is usually based on a medical history, an examination of the throat, and a rapid strep test or throat culture to test for strep bacteria. One or both of these tests are needed to confirm infection with strep bacteria.