What are the signs and symptoms of scarlet fever?

Signs and Symptoms of Scarlet Fever

Scarlet fever presents with a distinctive constellation of features: severe sore throat with pain on swallowing, high fever (typically 101-104°F), a characteristic sandpaper-like rash that begins on the trunk and spreads to extremities with perineal accentuation, and "strawberry tongue" (initially white-coated, then bright red with prominent papillae). 1, 2

Cardinal Clinical Features

Pharyngeal Manifestations

• Severe sore throat with pain on swallowing is the hallmark symptom 1
• Tonsillopharyngeal erythema with or without exudates is commonly present 1
• Palatal petechiae are frequently observed 1
• The pharyngeal findings distinguish scarlet fever from viral causes, which rarely produce exudative pharyngitis 1

Fever Pattern

• High fever typically ranging from 101-104°F (38-40°C) 1, 2
• Fever persists for at least 5 days if untreated 2
• The presence of fever is common, though its absence does not completely exclude the diagnosis 1

Characteristic Rash

• Distinctive sandpaper-like, maculopapular rash that is pathognomonic for the condition 3, 4, 5
• Begins on the trunk and spreads to extremities 2
• Accentuation in the perineal region with possible early desquamation 2
• Appears earlier in the illness course compared to other exanthematous diseases 2
• Rarely becomes petechial, helping distinguish it from Rocky Mountain Spotted Fever 2
• Does not typically involve palms and soles initially 2

Oral Cavity Changes

• "Strawberry tongue" or "raspberry tongue" - initially white-coated, then evolves to bright red with prominent papillae 1, 5
• This finding is indistinguishable from that seen in streptococcal infections 6
• May be the first sign noted by dental professionals 5

Other Clinical Features

• Headache and nausea/vomiting, especially in children 2
• Cervical lymphadenopathy, usually unilateral 2
• Bilateral bulbar conjunctival injection is NOT typical of scarlet fever (this distinguishes it from Kawasaki disease) 1

Key Distinguishing Features from Similar Conditions

Unlike Kawasaki Disease:

• Scarlet fever has exudative pharyngitis and responds rapidly to antibiotics within 24-48 hours 1
• Lacks bilateral bulbar conjunctival injection without exudate 6, 1

Unlike Viral Pharyngitis:

• Scarlet fever rarely presents with cough, hoarseness, or conjunctivitis 1
• Has sudden onset with severe throat pain, unlike the gradual onset of viral causes 2
• Lacks coryza (runny nose) typical of viral infections 2

Epidemiological Context

• Most common in children aged 5-15 years 1, 4
• Typically occurs in winter and early spring in temperate climates 1
• Highly contagious in crowded settings like kindergartens and schools 4, 7

Critical Clinical Pitfalls

Do not wait for the "classic" complete presentation before considering the diagnosis, as all features may not be present simultaneously and watchful waiting can delay treatment and increase complications 1. The diagnosis remains clinical, but laboratory confirmation with throat culture or rapid antigen detection test (RADT) is essential, as clinical scoring systems predict positive results only ≤80% of the time 1, 2.

Be aware of atypical presentations, particularly in adults where rash distribution may be limited to dorsum of hands and feet only 8. A high degree of suspicion is required to diagnose these rare presentations 8.