Scarlet fever is an infectious disease caused by Group A Streptococcus (Streptococcus pyogenes), the same bacteria responsible for strep throat. It is characterized by a bright red sandpaper-like rash and a strawberry tongue, making it a recognizable pediatric condition.
Although scarlet fever was once considered life-threatening, modern antibiotic treatment has made it highly manageable. However, untreated cases can still lead to serious complications, including rheumatic fever and kidney disease.
Pathophysiology
Scarlet fever arises when certain strains of Group A streptococcus release erythrogenic exotoxins, which trigger the characteristic rash and systemic symptoms.
Transmission: Droplet infection via coughing, sneezing, and close contact.
Signs and Symptoms
The disease typically begins with abrupt onset and progresses quickly.
Early Symptoms:
- Fever, chills, body aches
- Sore throat and painful swallowing
- Headache and malaise
Classic Features of Scarlet Fever:
Red, sandpaper-like rash
- Starts on the neck and chest, spreading outward to trunk and extremities
- Usually spares palms and soles
- Feels rough to touch, resembling sandpaper
Strawberry tongue
- Tongue appears red and bumpy with a white coating early, later bright red
These classic findings are often remembered as the “S’s of Scarlet Fever”:
- Strawberry tongue
- Sandpaper rash
Complications
Without prompt treatment, scarlet fever may progress to serious complications:
- Rheumatic fever → A post-streptococcal autoimmune condition affecting heart valves, joints, and skin.
- Glomerulonephritis → Inflammatory kidney disease following streptococcal infection.
- Peritonsillar abscesses → Localized throat infections that can obstruct the airway.
- Pneumonia → Spread of infection to the lungs.
Diagnosis
Diagnosis is primarily clinical, supported by laboratory tests:
- Rapid strep test or throat culture confirms Group A streptococcus.
- Physical exam reveals the classic rash, strawberry tongue, and pharyngitis.
Treatment
Scarlet fever is effectively treated with antibiotics.
1. Antibiotics
- Penicillin V: First-line treatment for 10 days.
- Amoxicillin: Common alternative.
- Erythromycin or azithromycin: For penicillin-allergic patients.
2. Supportive Care
- Plenty of fluids, soft foods, and soothing warm teas.
- Popsicles, slushies, and soups help ease throat pain.
- Cool mist humidifier to relieve throat dryness.
- Rest until fever subsides.
Important: Antibiotics must be taken for the full prescribed course to prevent relapse and complications, even if symptoms improve early.
Prevention
Scarlet fever is highly contagious. Preventive measures include:
- Hand hygiene and respiratory etiquette (covering coughs, sneezes).
- Avoid sharing utensils, cups, or toothbrushes.
- Keeping children home from school until at least 24 hours after starting antibiotics.
Prognosis
With early diagnosis and treatment, the prognosis of scarlet fever is excellent. Symptoms usually improve within 48 hours of antibiotic therapy, and the rash fades over a week. Rarely, untreated cases lead to long-term complications such as rheumatic heart disease.
Table: Scarlet Fever at a Glance
| Feature | Description |
|---|---|
| Cause | Group A Streptococcus (Streptococcus pyogenes) |
| Transmission | Droplet spread, close contact |
| Key Symptoms | Fever, sore throat, red sandpaper rash, strawberry tongue |
| Rash Distribution | Begins on neck & chest → spreads outward, spares palms & soles |
| Complications | Rheumatic fever, glomerulonephritis, abscesses, pneumonia |
| Treatment | Penicillin (or erythromycin if allergic), fluids, comfort measures |
| Prognosis | Excellent with early treatment, risk of severe complications if untreated |
FAQs on Scarlet Fever
Q1. Is scarlet fever still dangerous today?
Not usually, since antibiotics make it treatable. However, untreated infections can still cause life-threatening complications.
Q2. How long is scarlet fever contagious?
Without treatment, up to 2–3 weeks. With antibiotics, patients are usually non-contagious after 24 hours.
Q3. Can adults get scarlet fever?
Yes, but it is far more common in children aged 5–15.
Q4. What is the difference between strep throat and scarlet fever?
Strep throat is the primary infection. Scarlet fever occurs when the bacteria release toxins that cause the rash and strawberry tongue.
Q5. How quickly does scarlet fever improve with antibiotics?
Fever and sore throat often improve within 1–2 days, and rash fades within 5–7 days.
