Physiological Adaptation Q 61
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 is characteristic of rubella infection.
Option A: Bacteria called group A Streptococcus or group A strep cause scarlet fever. The bacteria sometimes make a poison (toxin), which causes a rash- the “scarlet” of scarlet fever. As the name “scarlet fever” implies, an erythematous eruption is associated with a febrile illness. The circulating toxin, produced by GABHS and often referred to as erythemogenic or erythrogenic toxin, causes the pathognomonic rash as a consequence of local production of inflammatory mediators and alteration of the cutaneous cytokine milieu. This results in a sparse inflammatory response and dilatation of blood vessels, leading to the characteristic scarlet color of the rash.
Option B: The tongue may have a “strawberry”-like (red and bumpy) appearance, which is a characteristic sign of scarlet fever. 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). Red, edematous, exudative tonsils are typically observed if the infection originates in this area.
Option D: The throat and tonsils may be very red and sore with scarlet fever, and swallowing may be painful. The mucous membranes usually are bright red and scattered petechiae and small red papular lesions on the soft palate are often present.