What is the etiology of scarlet fever in patients with group A streptococcal (GAS) infections?

Updated: Sep 07, 2018
  • Author: Zartash Zafar Khan, MD, FACP; Chief Editor: Pranatharthi Haran Chandrasekar, MBBS, MD  more...
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Answer

Scarlet fever results from pyrogenic exotoxin released by GAS and is characterized by a scarlatiniform rash that blanches with pressure. The rash usually appears on the second day of illness and fades within a week, followed by extensive desquamation that lasts for several weeks.

A history of recent exposure to another individual (eg, classroom or household contact) with streptococcal infection is a helpful clue. Isolation of S pyogenes from the pharynx confirms the diagnosis in uncertain cases, and serologic evidence of recent GAS infection may be present (ASO or anti-deoxyribonuclease B [anti-DNase B] antibody response).


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