Scarlet Fever (Scarlatina)
🌸 Scarlet fever (Scarlatina) is unlikely if the patient has cough, coryzal symptoms, or diarrhoea.
⏳ Without treatment, individuals may remain infectious for 2–3 weeks.
💊 Antibiotics reduce the infectious period to ~24 hours after treatment begins.
📖 About
- 👶 Primarily a childhood disease, most common between ages 2–8 years.
- 📈 UK notifications have increased in recent years, with outbreaks in schools and nurseries.
🦠 Aetiology
- Caused by toxin-producing strains of Streptococcus pyogenes (Group A Streptococcus, GAS).
- 💨 Spread via respiratory droplets or direct contact with infected secretions.
- ⏱️ Incubation: usually 2–5 days.
🔍 Clinical Features
- 🌸 Rash:
- Fine, punctate, papular rash starting on the trunk → spreads to neck & arms.
- Accentuated in flexures (Pastia’s lines).
- Spares palms & soles; feels like sandpaper.
- 👅 Strawberry tongue: red, swollen papillae, sometimes with a white coating initially.
- 🔥 Fever, sore throat/tonsillitis, malaise.
- 🤕 Tender anterior cervical lymphadenopathy.
⚠️ Complications
- Suppurative: Otitis media, peritonsillar abscess, sinusitis.
- Invasive GAS disease: Pneumonia, meningitis, septic arthritis, necrotising fasciitis.
- Post-infectious: Rheumatic fever, post-streptococcal glomerulonephritis.
🧾 Differential Diagnoses
- Measles (cough, coryza, conjunctivitis, Koplik spots).
- Rubella (milder, post-auricular nodes).
- Roseola (high fever then rash).
- Kawasaki disease (persistent fever >5 days, mucosal changes, coronary risk).
- Drug eruptions or allergic rashes.
🧪 Investigations
- 🔎 Usually a clinical diagnosis - classic rash + sore throat.
- Throat swab for Group A Strep (if diagnostic uncertainty).
- Bloods (ASO titre, inflammatory markers) only if complications suspected.
💊 Management
- Prevention:
- 🧼 Regular hand washing.
- 🚫 No sharing of utensils, bottles, or towels.
- 🗑️ Dispose of used tissues promptly.
- 🏫 Exclude from school/work until 24h after starting antibiotics.
- Treatment:
- 📌 First-line: Penicillin V for 10 days.
- 💊 Alternatives: Amoxicillin or Azithromycin if penicillin-allergic.
- Actions:
- Seek medical advice promptly if suspected.
- Complete the full antibiotic course to prevent complications.
- Reassure that with prompt treatment, prognosis is excellent.
📚 References
