The differential diagnosis of scarlet fever with pharyngitis includes multiple viral pathogens that can cause acute pharyngitis with a viral exanthema. Crowding, such as found in schools, military training facilities, and daycare centers, increases the risk of disease spread. The most common risk factor is close contact with another person with scarlet fever. It is rare in children younger than 3 years of age. It is most common among children 5 through 15 years of age. Scarlet fever can occur in people of all ages. The incubation period of scarlet fever is approximately 2 through 5 days. 12–24 hours after starting appropriate antibiotic therapy *.People with scarlet fever should stay home from work, school, or daycare until: Treatment with an appropriate antibiotic for 12 hours or longer limits a person’s ability to transmit group A strep. There is no evidence to indicate that pets can transmit the bacteria to humans.

Humans are the primary reservoir for group A strep. However, evidence from outbreak investigations indicate that environmental transmission of group A strep may be possible, although it is likely a less common route of transmission. Environmental transmission via surfaces and fomites was historically not thought to occur. Foodborne outbreaks of group A strep have occurred due to improper food handling. Although rare, spread of group A strep infections may also occur via food. Crowded conditions - such as those in schools, military training facilities, or daycare centers - facilitate transmission. People with scarlet fever are much more likely to transmit the bacteria to others than asymptomatic carriers. Typically transmission occurs through saliva or nasal secretions from an infected person. Group A strep infections, including scarlet fever, are most commonly spread through direct person-to-person transmission. The eventual disappearance of the coating can result in a “strawberry tongue.” Transmission A yellowish white coating with red papillae may initially cover the tongue. In addition, the face may appear flushed and the area around the mouth may appear pale (i.e., circumoral pallor). The rash usually persists for about one week and desquamation may follow. Streptococcus pyogenes (group A Streptococcus) on Gram stain. Begins on the trunk, then quickly spreads outward, usually sparing the palms and solesįigure 1.Accentuation of the red rash in flexor creases (i.e., under the arm, in the groin), termed “Pastia’s lines”.Erythematous rash that blanches on pressure.It can also follow group A strep pyoderma or wound infections.Ĭharacteristics of the rash typically include: Scarlet fever, also called scarlatina, is characterized by a scarlatiniform rash and usually occurs with group A strep pharyngitis. They belong to group A in the Lancefield classification system for β-hemolytic Streptococcus, and thus are called group A streptococci. They exhibit β-hemolysis (complete hemolysis) when grown on blood agar plates. pyogenes are gram-positive cocci that grow in chains ( see figure 1). Scarlet fever is an illness caused by pyrogenic exotoxin-producing S. Streptococcus pyogenes, which is also called group A Streptococcus (group A strep), cause scarlet fever.

Clindamycin skin rash