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Scarlet Fever
Abd El-Salam Dawood MD
Interventional Pediatric Cardiologist
FIBMS-Ped FIBMS-PedCard
Scarlet fever is the result of infection by group A
streptococci that elaborate any of the 3 pyrogenic
(erythrogenic) exotoxins (A, B, or C).
It is now encountered less commonly and is less
virulent than in the past.
The primary focus of infection is most commonly
pharyngitis, but infection may be secondary to a
wound or skin infection (surgical scarlet fever) or
have some other focus.
The incubation period: 1-7 days.
The onset is acute and is characterized by fever, chills,
vomiting, headache, and toxicity.
A
generalized
sunburn
like,
“scarlatiniform”
exanthem soon becomes apparent accentuated in the
axillae, groin, and neck and is characterized by
punctate red macules or fine papules that blanch on
pressure. Petechiae may be present, especially on the
distal extremities. In some individuals, it may feel like
coarse sandpaper (goose-pimple or sand paper).
Areas of hyperpigmentation that do not blanch with
pressure may appear in the deep creases, particularly
in the antecubital fossae (i.e., Pastia lines). The
cheeks appear flushed, with sparing of the area around
the mouth (i.e., circumoral pallor). The pharynx is
inflamed, and the tonsils are hyperemic and
edematous and may be covered with a gray-white
exudate. The tongue may be edematous and
reddened initially, with a white coating through which
protrude red papillae (i.e., white strawberry tongue).
After several days the white coat desquamates,
leaving a red tongue studded with prominent papillae
(i.e., red strawberry tongue, raspberry tongue). The
palate and uvula may be reddened and covered with
petechiae.
The exanthem and enanthem of scarlet fever tend to
parallel the fever course, lasting 5 to 7 days in the
untreated patient; early antibiotic treatment may
mitigate the physical findings. Desquamation begins
on the face in fine flakes toward the end of the first
week and continues over the trunk, ultimately involving
the hands and feet.
The exanthem of streptococcal scarlet fever is not
diagnostic of a streptococcal infection; other
organisms can cause a similar rash, including several
toxigenic stains of S. aureus and Arcanobacterium
haemolyticum.
Because of the difficulty in distinguishing the causative
agent, when the cause of illness is uncertain it may be
prudent to treat patients with scarlet fever with a
cephalosporin or ß-lactamase– resistant penicillin
10 days (erythromycin for allergics). Supportive
treatment is needed.
Scarlet fever must also be
differentiated from other exanthematous diseases,
including measles, rubella, human parvovirus disease,
and other viral exanthems. Kawasaki syndrome should
also be considered, especially in younger children.