Scarlet fever is a nonsuppurative complication of group A streptococcal infection. While it usually occurs following a throat infection, a minority of cases result from a skin infection.
Presentation
Scarlet fever usually begins with fever, sore throat, and systemic symptoms (e.g., nausea, vomiting, malaise). The patient may also complain of headache, abdominal and myalgias. A characteristic rash with diffuse erythema and small papular elevations usually appears within 48 hours of illness onset. The patient may also develop a bright red tongue with prominent papillae (a.k.a., strawberry tongue). Resolution of the rash is followed by desquamation of the skin.
Pitfalls
The strawberry tongue is NOT pathognomonic; it can occur in other conditions as well (e.g., Kawasaki disease, toxic shock syndrome, multisystem inflammatory syndrome in children).
Images from patients with scarlet fever
Rash characteristics |
|---|
Diffuse erythema that blanches with pressure |
Most marked in the skin folds, where Pastia lines (i.e., confluent petechia) may appear |
Numerous small papular elevations give a sandpaper quality on palpation |
Visually likened to a boiled lobtser or a bad sunburn |
Circumoral pallor |
​The palms and soles are usually spared |
Evaluation
The diagnosis is made clinically. Microbiologic testing (e.g., throat culture, rapid antigen detection test) can confirm infection with group A streptococcus.
Management
Treatment is the same as for a streptococcal throat infection; antibiotics must target Streptococcus pyogenes. Twenty-four hours after the child begins taking antibiotics, they may return to school or daycare without posing a risk to the other children.
Pitfalls
The rash does NOT need to be treated separately.
Recommended Reading
Video Lectures
References
Wessels MR. Pharyngitis and Scarlet Fever. 2016 Feb 10 [Updated 2016 Mar 25]. In: Ferretti JJ, Stevens DL, Fischetti VA, editors. Streptococcus pyogenes : Basic Biology to Clinical Manifestations [Internet]. Oklahoma City (OK): University of Oklahoma Health Sciences Center; 2016-. Available from: https://www.ncbi.nlm.nih.gov/sites/books/NBK333418
Basetti S, Hodgson J, Rawson TM, Majeed A. Scarlet fever: a guide for general practitioners. London J Prim Care (Abingdon). 2017;9(5):77-79. Published 2017 Aug 11. doi:10.1080/17571472.2017.1365677
Kliegman, Robert. Nelson Textbook of Pediatrics. Edition 21. Philadelphia, PA: Elsevier, 2020.