Scarlet fever is an exanthematous disease caused by an infection of Group A streptococcus.
Group A streptococcus is also responsible for other conditions such as pharyngitis, erysipelas, and impetigo.
In the case of scarlet fever, it involves bacteria producing a distinctive toxin. This infection primarily affects individuals lacking antibodies against the toxin or those who exhibit an exaggerated response to it.
The infection manifests in the tonsils and is characterized by a distinctive skin rash associated with the toxin.
Scarlet fever typically begins with fever and a sore throat. Within a couple of days, a red rash emerges on the neck, extending down to the trunk and subsequently spreading to the limbs, but it does not affect the palms of the hands and the soles of the feet.
The skin presents a fine, sandpaper-like rash with a vivid red appearance in the armpits and groin. Characteristically, applying pressure to the skin results in a color change from red to white.
The rash may persist for about a week and can lead to peeling, particularly in areas such as the fingertips, hands, feet, and groin.
The condition is often accompanied by general discomfort, chills, abdominal pain, headache, vomiting, and, notably, a red and swollen tongue (referred to as strawberry tongue) and pronounced paleness around the mouth.
Scarlet fever is transmitted through direct contact with respiratory secretions, such as coughing or sneezing, from infected individuals.
Additionally, transmission can occur by contact with contaminated objects and through the sharing of utensils, like plates, glasses, or cutlery.
Scarlet fever can be diagnosed by physical examination and the characteristic rash.
A throat swab may be conducted to culture Group A streptococcus for confirmation.
Scarlet fever is treated with antibiotics, primarily from the penicillin group, to prevent the rheumatic, renal, and cardiac complications typical of an inadequately treated streptococcal infection.