scarlet fever

scarlet fever
Name	Scarlet fever
Synonyms	Scarlatina
Caption	Characteristic "strawberry tongue" often seen in patients.
Field	Infectious disease, Pediatrics
Symptoms	Sore throat, fever, red rash, strawberry tongue
Complications	Rheumatic fever, Post-streptococcal glomerulonephritis, Otitis media
Onset	2–5 days after exposure
Duration	About 1 week
Causes	Group A *Streptococcus pyogenes*
Risks	Close contact, crowded settings
Diagnosis	Based on symptoms, Rapid strep test, Throat culture
Prevention	Hand hygiene, avoiding sick individuals
Treatment	Antibiotics (e.g., Penicillin, Amoxicillin)
Prognosis	Excellent with treatment
Frequency	Common in children

Scarlet fever, historically known as scarlatina, is an infectious disease caused by specific strains of the bacterium *Streptococcus pyogenes* that produce erythrogenic toxins. The illness is classically characterized by a distinctive red rash, sore throat, and high fever, primarily affecting children. While once a major cause of childhood mortality, the advent of Antibiotics has dramatically reduced its severity and incidence in many parts of the world.

Signs and symptoms

The initial phase often resembles Strep throat, featuring a sudden onset of fever, sore throat, headache, and chills. Within one to two days, the characteristic fine, red, sandpaper-like rash appears, typically starting on the chest and abdomen before spreading to other areas like the Neck and Groin. The face may appear flushed with circumoral pallor, and the tongue may progress through a "white strawberry" to a "red strawberry" appearance. Other signs can include Pastia's lines, which are red lines in the skin folds, and subsequent desquamation, or peeling, of the skin on the fingertips and toes as the rash fades.

Causes and transmission

The disease is caused exclusively by infection with strains of the bacterium *Streptococcus pyogenes*, also known as group A *Streptococcus*, that carry bacteriophages encoding for pyrogenic exotoxins, historically known as the Dick test toxins. These toxins, including types A, B, and C, are responsible for the characteristic rash. Transmission occurs primarily through respiratory droplets from coughs or sneezes of an infected person, or less commonly through contact with contaminated objects or skin lesions in cases of Impetigo. Outbreaks are often associated with settings like Schools and Day care centers.

Diagnosis

Diagnosis is primarily clinical, based on the presentation of the characteristic rash alongside symptoms of Pharyngitis. Confirmation typically involves testing for the presence of the causative bacterium. A Rapid strep test performed on a throat swab can provide quick results, though a negative test is often followed by a Throat culture, which is considered the gold standard for detecting GAS. In some cases, blood tests such as an Anti-DNase B titer or Antistreptolysin O titer may be used to confirm a recent infection, particularly when investigating potential complications.

Treatment and prevention

The mainstay of treatment is a course of Antibiotics, which reduces the duration of symptoms, limits transmission, and most importantly, prevents serious complications. Penicillin or Amoxicillin are typically the first-line agents, with alternatives like Azithromycin or Clindamycin used for patients with Penicillin allergy. Supportive care includes rest, fluids, and medications like Acetaminophen for fever. Prevention focuses on good respiratory hygiene, frequent handwashing, and avoiding close contact with infected individuals. There is no Vaccine available, though historical efforts were made, such as those by George Frederick Dick and Gladys Henry Dick.

Complications

Although now rare with prompt antibiotic treatment, potential complications can be serious and are typically divided into suppurative and non-suppurative types. Suppurative complications arise from direct spread of the infection and can include Otitis media, Sinusitis, Peritonsillar abscess, and Pneumonia. The more significant non-suppurative, immune-mediated complications include Acute rheumatic fever, which can lead to Rheumatic heart disease, and Post-streptococcal glomerulonephritis, a kidney disorder. Other rare sequelae can involve the Central nervous system, such as Sydenham chorea.

Epidemiology

Scarlet fever was a common and feared disease of childhood in the 19th century and early 20th century, with major epidemics occurring in places like the United States and United Kingdom. Its incidence declined sharply in the Antibiotic era but has shown periodic resurgences in some regions, including parts of Asia and the United Kingdom in the 2010s. It most frequently affects children between the ages of 5 and 15 years and is uncommon in adults due to acquired immunity. Seasonal patterns are observed, with higher rates typically in Winter and early Spring.

Category:Bacterial diseases Category:Pediatrics