Scarlet fever should be strongly suspected in a child or adolescent who presents with the triad of sore throat, fever (>100.4°F [>38.0°C]), and a scarlatiniform abdominal rash (i.e., a diffuse, finely papular, erythematous rash that feels like sandpaper and blanches with pressure).
Scarlet fever can occur at any age but mainly affects children ages 1-10 years, and it is most common in those ages 3-6 years. It is uncommon in children <1 year old and in adults.
A rapid antigen detection test for group A streptococcus (GAS) from a throat swab should be performed in all patients ages 3-14 years who present with GAS pharyngitis and a scarlatiniform rash. Testing is not routinely recommended in children <3 years old and in children with obvious viral clinical and epidemiologic features (e.g., rhinorrhea, hoarseness, mouth ulcers).
Antibiotics (e.g., oral penicillin V or amoxicillin) should be given only to patients with microbiologically confirmed GAS infection (i.e., positive rapid antigen detection test, polymerase chain reaction test, or throat/skin swab culture).
Scarlet fever and the scarlatiniform rash generally self-resolve within 7 days. However, early treatment with antibiotics shortens the intensity and duration of symptoms of the primary GAS infection, reduces the risk of early and late complications such as rheumatic fever and invasive GAS infection, and reduces the risk of onward transmission.
Scarlet fever (scarlatina) is an exotoxin-mediated infectious disease associated with a characteristic erythematous rash of the skin and tongue. It commonly results from group A streptococcus (GAS) infection of the throat or, less commonly, the skin. Patients typically present with sore throat, fever (>100.4°F [>38.0°C]), and a scarlatiniform abdominal rash (a diffuse, finely papular, erythematous rash that feels like sandpaper and blanches with pressure).
Scarlet fever can occur at any age but mainly affects children ages 1-10 years and is most common in those ages 3-6 years. It is uncommon in children <1 year old or in adults. GAS pharyngitis and scarlet fever have similar epidemiology, evaluation, and treatment. See Acute pharyngitis.
This topic covers scarlet fever in children and adults.
History and exam
Key diagnostic factors
- scarlatiniform rash
- fever (>100.4°F [>38.0°C])
- sore throat
- tonsillopharyngeal inflammation
- tonsillopharyngeal exudate
- palatal petechiae
- anterior cervical adenitis
- no cough
Other diagnostic factors
- strawberry tongue
- skin desquamation
- abdominal pain
- group A streptococcus (GAS) pharyngitis
- close contact with a person with scarlet fever or other group A streptococcus (GAS) presentation
- age 1-10 years
- winter and spring seasons
- crowded environment
- close contact with children ages 1-10 years
- nonpharyngitis group A streptococcus (GAS) infection
1st investigations to order
- rapid antigen detection test (RADT) for group A streptococcus (GAS)
Investigations to consider
- bacterial culture (throat, skin, wound)
- polymerase chain reaction for group A streptococcus (GAS)
- Kawasaki disease
- Erythema infectiosum (parvovirus B19, fifth disease)
- Scarlet fever: information for clinicians
- Group A streptococcal (GAS) pharyngitis: a practical guide to diagnosis and treatment
TonsillitisMore Patient leaflets
Sore Throat (Pharyngitis) Evaluation and Treatment Criteria (McIsaac)More Calculators
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