Scarlet Fever

Question 1

Definition of scarlet fever

Answer 1

A notifiable infectious disease caused by toxin-producing strains of the bacterium Streptococcus Pyogenes (Group A Strep)

Question 2

Definition of a scarlet fever ‘outbreak’

Answer 2

‘a credible report of two or more probable or confirmed scarlet fever cases attending the same school or nursery or other childcare setting, notified within 10 days of each other.’

Question 3

Peak age of incidence of scarlet fever

Answer 3

• Most common between the ages of 2-8 (median age 4 years)

Question 4

Pathophysiology of scarlet fever including transmssion

Answer 4

• GAS bacteria can colonise the throat (primary site is pharyngitis) or skin (3-26% of children carry GAS asymptomatically)
• The rash and fever associated with scarlet fever are due to exotoxin and superantigen release by GAS
• Scarlet fever is highly contagious and is transmitted when a person’s mouth, throat, or nose comes into contact with infected saliva or mucus by aerosol transmission or by direct contact with contaminated surfaces

Question 5

Incubation period for scarlet fever

Answer 5

Usually 2–3 days but can range from 1–6 days

Question 6

Risk factors for developing scarlet fever

Answer 6

Children who are immunocompromised or immunosuppressed, have skin breakdown, concurrent chickenpox or influenza

Question 7

Complications of scarlet fever infection

Answer 7

Suppurative complications due to local spread of infection (otitis media, throat infection and abscess, acute sinusitis and mastoiditis), non suppurative complications (rheumatic fever, glomerulonephritis) and life-threatening complications (meningitis, endocarditis, cellulitis, sepsis)

Question 8

Presentation of scarlet fever

Answer 8

• Initial clinical features may be non-specific and include: sore throat, fever (typically greater than 38.3 degrees), headache, fatigue, vomiting
• An erythematous blanching rash (macular papular) usually develops on the trunk 12–48 hours after initial symptoms, before spreading to the rest of the body and flexures
• The rash will have a pinpoint sandpaper like texture
• It usually spreads rapidly to the face, trunk and extremities with increased density around the neck, axillae or groin
• Palms and soles are typically spared
• Skin may peel after resolution
• Strawberry tongue— initially the tongue is covered with a white coat through which red papillae may be seen. Later, the white covering disappears, leaving the tongue with a beefy red appearance. There may be circumoral pallor
• May be associated with cervical lymphadenopathy
• May also get desquamation of the fingers

Question 9

Investigations for scarlet fever

Answer 9

• Consider taking a throat swab for culture of Group A streptococcus (GAS) if there is uncertainty about diagnosis, the case is suspected to be part of an outbreak, or the child has a true penicillin allergy

Question 10

Management of scarlet fever

Answer 10

• Notify the local Health Protection Unit (HPU)
• Arrange urgent hospital admission if the child has severe symptoms or high-risk of developing complications
• If hospital admission is not needed prescribe phenoxymethylpenicillin (penicillin V) four times a day for 10 days first-line
• Consider amoxicillin as an alternative if phenoxymethylpenicillin is not tolerated
• Prescribe azithromycin one a day for 5 days for children with a true penicillin allergy
• Advise on the use of over-the-counter paracetamol or ibuprofen for symptom relief, encourage fluid intake and cleaning of any skin breaks

Question 11

Is school exclusion required for scarlet fever

Answer 11

Exclusion from nursery, school, or work is needed for at least 24 hours after starting appropriate antibiotic treatment

Question 12

How should scarlet fever be followed up

Answer 12

Advise the person to arrange follow up if symptoms worsen or have not improved after 7 days