Scarlet fever

Scarlet fever should be strongly suspected in a child or adolescent who presents with the triad of sore throat, fever (>38.0°C [>100.4°F]), 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 aged 1 to 10 years, and it is most common in those aged 3 to 6 years. It is uncommon in children <1 year old and in adults.

Diagnosis is mainly clinical. However, a throat swab for culture of group A streptococcus (GAS) can be considered in some patients (e.g., if the diagnosis is uncertain), although antibiotics should be given without waiting for the result. In some countries, microbiological confirmation of GAS infection is required via a positive rapid antigen detection test, polymerase chain reaction test, or throat/skin swab culture prior to starting antibiotics.

Scarlet fever is a notifiable disease in China, South Korea, and many European countries including England, Wales, Northern Ireland, Austria, and Poland.

Scarlet fever and the scarlatiniform rash generally self-resolve within 7 days. However, early treatment with antibiotics (e.g., phenoxymethylpenicillin) 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.[1]Vorel E, Greenfield M. Scarlet fever. In: Ferri FF, ed. Ferri's clinical advisor 2022. New York, NY: Elsevier; 2022:1340.e2-1340.e3. Patients typically present with sore throat, fever (>38°C [>100.4°F]), and a scarlatiniform abdominal rash (a diffuse, finely papular, erythematous rash that feels like sandpaper and blanches with pressure).[2]Shulman ST, Bisno AL, Clegg HW, et al. Clinical practice guideline for the diagnosis and management of group A streptococcal pharyngitis: 2012 update by the Infectious Diseases Society of America. Clin Infect Dis. 2012 Nov 15;55(10):e86-102. [Erratum in: Clin Infect Dis. 2014 May;58(10):1496.] https://academic.oup.com/cid/article/55/10/e86/321183 http://www.ncbi.nlm.nih.gov/pubmed/22965026?tool=bestpractice.com [3]American Academy of Pediatrics. Group A streptococcal infections. In: Kimberlin DW, Barnett ED, Lynfield R, et al, eds. Red book: 2021-2024 report of the Committee on Infectious Diseases, 32nd ed. Itasca, IL: American Academy of Pediatrics; 2021. https://publications.aap.org/redbook ​​[4]World Health Organization. International statistical classification of diseases and health related problems (ICD). 11th revision. 2022 [internet publication]. https://icd.who.int/en

Scarlet fever can occur at any age but mainly affects children aged 1 to 10 years and is most common in those aged 3 to 6 years. It is uncommon in children aged <1 or in adults.[5]Lamagni T, Guy R, Chand M, et al. Resurgence of scarlet fever in England, 2014-16: a population-based surveillance study. Lancet Infect Dis. 2018 Feb;18(2):180-7. https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(17)30693-X/fulltext http://www.ncbi.nlm.nih.gov/pubmed/29191628?tool=bestpractice.com [6]Liu Y, Chan TC, Yap LW, et al. Resurgence of scarlet fever in China: a 13-year population-based surveillance study. Lancet Infect Dis. 2018 Aug;18(8):903-12. https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(18)30231-7/fulltext http://www.ncbi.nlm.nih.gov/pubmed/29858148?tool=bestpractice.com [7]Staszewska-Jakubik E, Czarkowski MP, Kondej B. Scarlet fever in Poland in 2014. Przegl Epidemiol. 2016;70(2):195-202. http://www.ncbi.nlm.nih.gov/pubmed/27779834?tool=bestpractice.com GAS pharyngitis and scarlet fever have similar epidemiology, evaluation, and treatment. See our topic Acute pharyngitis.

This topic covers scarlet fever in children and adults.