Scarlet Fever
Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management
Definition
Scarlet fever is an infectious disease caused by toxin-producing strains of Group A Streptococcus (GAS), characterised by fever, pharyngitis, and a characteristic erythematous rash.
Aetiology
- Caused by Streptococcus pyogenes (Group A Streptococcus).
- Transmission occurs via respiratory droplets or direct contact with infected secretions.
Pathophysiology
- Bacteria produce erythrogenic toxins, leading to widespread capillary dilation and rash formation.
- Inflammatory response causes pharyngitis and systemic symptoms.
Risk Factors
- Children aged 5-15 years (most commonly affected).
- Close contact with infected individuals.
- Winter and early spring (higher transmission rates).
Signs and Symptoms
- Fever: often high grade and sudden onset.
- Sore throat: erythematous pharynx with exudates.
- Strawberry tongue: white coating initially, followed by bright red tongue with prominent papillae.
- Rash: fine, sandpaper like texture, starting on the trunk and spreading.
- Facial flushing: with circumoral pallor.
- Skin peeling: occurs during the convalescent phase.
Investigations
- Throat swab culture: confirms Group A Streptococcus infection.
- Rapid antigen detection test (RADT): useful for rapid diagnosis.
- Full blood count (FBC): may show leukocytosis.
Management
1. Antibiotic Therapy:
- Penicillin V for 10 days (first-line treatment).
- Azithromycin or clarithromycin if penicillin allergy.
2. Supportive Care:
- Paracetamol or ibuprofen for fever and throat pain.
- Encourage fluid intake and rest.
3. Prevention:
- Good hand hygiene and avoidance of close contact with infected individuals.
- Children should be excluded from school until at least 24 hours after starting antibiotics.
4. Referral:
- Paediatrics: if complications such as rheumatic fever, post-streptococcal glomerulonephritis, or peritonsillar abscess develop.