Scarlet Fever

Duration

depends on agent used

First Line

Phenoxymethylpenicillin PO for 10 days 500 mg every 6 hours; increased if necessary up to 1 g every 6 hours

or  Clarithromycin PO for 5 days 250 - 500 mg twice daily

Clarithromycin should not be prescribed concurrently with ciclosporin, sirolimus and tacrolimus.

Notes

Scarlet fever is a notifiable infectious disease caused by toxin producing strains of Group A streptococcus (S. pyogenes). Group A Streptococci are universally penicillin susceptible.

The primary site of infection is usually the throat and the initial symptoms of Scarlet fever are those of streptococcal pharyngitis. A faint red rash, which feels like sand-paper, develops after 12-48hrs. Sparing of the area around the mouth is typical. As the rash fades, the skin of the fingertips, toes and groin peels off. The tongue first shows a white coating, then peels a few days later and looks red and swollen ('strawberry tongue').

Consider admission for any patient with valvular disease or significant immunocompromise or if you suspect a complication of streptococcal infection such as acute rheumatic fever or a deep neck space infection. 'Septic' or 'toxic' scarlet fever is associated with invasive Group A streptococcal disease. Patients develop a high fever and marked systemic toxicity, and may have symptoms such as diarrhoea and vomiting, arthralgia and jaundice. This is a medical emergency with a high mortality that should be admitted immediately.

Scarlet fever is a clinical diagnosis and throat swabs to identify S. pyogenes may not be helpful, due to poor specificity and sensitivity.

Advise the patient to stay away from school or work for at least 1 day after starting antibiotic treatment, wash their hands frequently, avoid sharing eating utensils and towels, dispose of handkerchiefs promptly, and avoid contact with anyone at particular risk of infection (e.g. people with valvular disease or who are immunocompromised). Advise to return for follow up if symptoms have not improved or have worsened after 7 days.