Scarlet fever

ABSTRACT Scarlet fever is an acute infectious disease caused by toxin-producing strains of Streptococcus pyogenes (Group A β-hemolytic Streptococcus). Although the disease is classically characterized by fever, pharyngitis, and a diffuse erythematous rash, its clinical presentation can overlap with several other febrile exanthems, making timely diagnosis essential for preventing complications. In recent years, multiple countries have reported a noticeable resurgence in scarlet fever cases, driven by factors such as increased transmission in school-aged populations, emergence of new streptococcal emm types, improved surveillance systems, and changes in population immunity. This review compiles evidence from clinical studies, laboratory investigations, epidemiological reports, and national guidelines to provide a comprehensive understanding of scarlet fever in the modern context. The methods summarize current diagnostic approaches including clinical assessment, rapid antigen detection tests (RADT), throat culture, and nucleic acid amplification tests, while also comparing variations in diagnostic recommendations across countries. Results highlight distinct clinical characteristics, evolving epidemiological patterns, and the influence of health-system limitations such as access to testing and antibiotic stewardship policies. Overall, the review underscores the importance of early diagnosis, public health surveillance, and guideline harmonization to reduce disease burden. Continued monitoring of antimicrobial resistance, development of preventive strategies, and research into Group A Streptococcus vaccine development remain essential priorities. INTRODUCTION Scarlet fever, also known as scarlatina, is a toxin-mediated illness resulting from strains of Group A Streptococcus producing pyrogenic exotoxins. The disease primarily affects children aged 5–15 years but can occur in any age group. Classic manifestations include sore throat, “sandpaper” rash, strawberry tongue, and fever. Historically a severe childhood disease, the incidence dramatically decreased following the introduction of antibiotics. However, the past decade has seen notable resurgences in regions such as the United Kingdom, East Asia, and Europe. Multiple factors—including bacterial strain mutations, improved surveillance, and population density—may contribute. Understanding the disease’s clinical patterns, diagnostic approaches, and challenges is essential for effective control.