A child is seen in the emergency department for scarlet fever. Which of the following descriptions of scarlet fever is not correct?
A. Scarlet fever is caused by infection with group A Streptococcus bacteria.
B. “Strawberry tongue” is a characteristic sign.
C. Petechiae occur on the soft palate.
D. The pharynx is red and swollen.
Correct Answer: C. Petechiae occur on the soft palate.
Petechiae on the soft palate are characteristic of rubella infection. Postnatal infection with rubella can be asymptomatic in approximately 25% to 50% of the patients, especially in young children. The incubation period ranges from 14 to 21 days and is followed by a prodromal illness characterized by low-grade fever, malaise, anorexia, headaches, sore throat, and adenopathy.
Option A: It is caused by streptococcal pyrogenic exotoxins (SPEs) types A, B, and C produced by group A beta-hemolytic streptococci (GABHS) found in secretions and discharge from the nose, ears, throat, and skin. The causative bacteria is Streptococcus pyogenes, which generates an endotoxin mainly responsible for the skin manifestation of the infection. This is further classified as group A and referred to as Group A Strep (GAS).
Option B: On day 1 or 2, the tongue is heavily coated with a white membrane through which edematous red papillae protrude (classic appearance of white strawberry tongue). By day 4 or 5, the white membrane sloughs off, revealing a shiny red tongue with prominent papillae (red strawberry tongue).
Option D: Red, edematous, exudative tonsils are typically observed if the infection originates in this area. Typically, scarlet fever is associated with acute pharyngitis. As a result, fever, sore throat, pain with swallowing, and cervical adenopathy is present.