Scarlet fever is an acute febrile illness, primarily affecting young children, caused by group A b-hemolytic streptococci. Recently group C streptococci have been implicated as well. Clinical manifestations include acute onset with fever, sore throat, headache, vomiting, and abdominal pain followed by a distinctive exanthem in 1 to 2 days.
There are both an exanthem and an enanthem associated with scarlet fever. They are caused by an erythrogenic toxin elaborated by the streptococcal organism. The tonsils and pharynx are red and covered with exudate, although occasionally pharyngeal findings are minimal. The tongue has a white coating through which red and hypertrophied papillae project, creating the appearance of a "white strawberry tongue." The white coating disappears by day 4 or 5, and the tongue acquires a bright-red appearance, the "red strawberry tongue." Bright-red or hemorrhagic spots may be seen on the soft palate or anterior pillars of the tonsillar fossae.
The exanthem of scarlet fever begins 1 or 2 days after the onset of the illness. It starts on the neck, axillae, and groin, spreading to the trunk and extremities. The rash is red and finely punctate, consisting of 1- to 2-mm papules giving the rash a characteristic rough, sandpaper feel. It is sometimes easier to identify the rash by palpation. The rash blanches with pressure. Linear petechial eruptions, Pastia's lines, are often present in the antecubital and axillary folds. There is facial flushing with circumoral pallor. A brawny desquamation occurs at 2 weeks, yielding fine flakes of dry skin.
The diagnosis of scarlet fever is readily made on clinical grounds. Throat swabs usually culture group A b-hemolytic streptococci, although group C may be cultured as well. Treatment with antibiotics is necessary to reduce the incidence of rheumatic fever and nephritis and will probably ameliorate the course of the disease. Penicillin is the antibiotic of choice, or erythromycin for those who are penicillin-allergic.
Was this article helpful?