Scarlet Fever
Scarlet fever is a bacterial infection caused by group A β-hemolytic streptococci (GAS) that produces pyrogenic exotoxins, characterized by fever, sore throat, and a distinctive sandpaper-like rash accompanied by specific oral manifestations including strawberry tongue. 1
Clinical Presentation
Cardinal Features
- Fever: High-grade fever typically ranging from 101°F to 104°F (39°C to 40°C) 1
- Sore throat: Sudden onset, severe with pain on swallowing 2, 1
- Distinctive rash: Appears within 1-2 days after fever onset 1
- Erythematous, sandpaper-like, papular rash
- Extensive involvement of trunk and extremities
- Accentuation in the perineal region with early desquamation
Oral and Pharyngeal Findings
- Tonsillopharyngeal erythema with or without exudates 2, 1
- Strawberry tongue (erythematous with prominent fungiform papillae) 1, 3
- Erythema, dryness, fissuring, peeling, cracking, and bleeding of the lips 1
- Soft palate petechiae 1
- Beefy red, swollen uvula 2, 1
Other Clinical Features
- Headache, nausea, vomiting, and abdominal pain (especially in children) 2, 1
- Tender, enlarged anterior cervical lymph nodes (lymphadenitis) 2, 1
- Desquamation of fingers and toes beginning 1-3 weeks after initial symptoms 2, 1
- Beau's lines (deep transverse grooves across the nails) may appear 1-2 months after onset 2
Epidemiology
- Primarily affects children between 5-15 years of age 2, 4
- More common in winter and early spring in temperate climates 2
- Highly contagious, transmitted through direct contact with saliva and nasal fluids 4
- May also arise from streptococcal wound infections or burns 4
Diagnosis
- Clinical diagnosis based on characteristic signs and symptoms 2, 1
- Microbiological confirmation is required through:
- Throat culture (gold standard) or
- Rapid antigen detection test (RADT) for GAS 1
Differential Diagnosis
- Viral infections (measles, adenovirus, enterovirus, Epstein-Barr virus) 2
- Staphylococcal scalded skin syndrome 2
- Toxic shock syndrome 2
- Kawasaki disease 2
- Drug hypersensitivity reactions 2
- Other bacterial causes of pharyngitis 2
Treatment
- Antibiotic therapy is essential to:
- Eradicate the infecting organism from the pharynx
- Prevent complications
- Reduce contagiousness 2
First-line Treatment
- Penicillin is the drug of choice for non-allergic patients due to its:
- Narrow spectrum of antimicrobial activity
- Infrequent adverse reactions
- Modest cost 2
Alternative Treatments (for penicillin-allergic patients)
- First or second-generation cephalosporins (if no immediate hypersensitivity to β-lactams) 2
- Macrolides (though resistance rates can be high) 5
Duration of Treatment
- Oral therapy: Complete 10-day course 2
- Intramuscular benzathine penicillin G: Single dose (preferred for patients unlikely to complete oral therapy) 2
Complications
Without appropriate treatment, scarlet fever can lead to:
Management of Contacts
- It is generally not necessary to perform throat cultures or provide treatment for asymptomatic household contacts 2
- Exception: Situations with increased risk of frequent infections or non-suppurative sequelae 2
- In institutional outbreaks (schools, day care centers):
- Throat cultures should be performed for all patients
- Only those with positive cultures should receive antimicrobial treatment 2
Prognosis
- With appropriate antibiotic therapy, fever typically resolves within 2 days 2
- Without treatment, fever may persist for a mean of 11 days (up to 3-4 weeks) 2
- Complete recovery is expected with proper treatment 4
Prevention
- No vaccine is currently available 4
- Early diagnosis and treatment are crucial to reduce complications and transmission 4, 3
- Basic hygiene measures help limit spread in community settings 6