Photo Credit CDC
Although not as common as it was in our great-grandparent's day, Scarlet Fever (aka scarlatina) remains a seasonal threat, affecting a small percentage of people who contract strep throat. It’s incidence usually peaks during the winter and spring.
Scarlet fever is caused by the same bacteria that causes `strep throat’ (Group A Streptococcus), and is characterized by fever, a very sore throat, a whitish coating or sometimes `strawberry’ (red & bumpy) tongue, and a rough feeling `scarlet rash’ that first appears on the neck and chest.
It primarily affects children under the age of 12. Adults generally develop immunity as they grow older. Untreated, this bacterial infection can lead to:
- Rheumatic fever
- Kidney disease
- Ear infections
- Skin infections
- Abscesses of the throat
In 2011 and 2012 we followed an unusual erythromycin resistant (but still sensitive to Penicillin & other 1st generation cephalosporins) scarlet fever outbreak in Hong Kong (see Hong Kong: Scarlet Fever In 2012), which sadly, resulted in a small number of fatalities.
While less common, a more serious yet related illness is call iGAS (invasive Group A Strep), which indicates infection of the bloodstream, deep tissues, or lungs, and may result in severe (and frequently fatal) cases of necrotizing fasciitis and streptococcal toxic shock syndrome.
This year, Public Health England is reporting a sharp rise in scarlet fever cases, with the highest number of cases reported in the first two months of the year since 1990; a number roughly double that seen in recent years. Scarlet fever outbreaks tend to be cyclical, with peaks occurring roughly every 4 years.
Advance Access report published on: 4 March 2014
Group A streptococcal infections: seasonal activity, 2013/14
Surveillance data for group A streptococcal (Streptococcus pyogenes; GAS) infections are indicating higher levels of scarlet fever incidence so far this season (2013/14) than seen in recent years. Increased levels of invasive and non-invasive GAS infection typically occur between December and April, with peak season usually in March/April. An update on the current seasonal activity for group A streptococcal infections is given below.
Routine monitoring of surveillance data has identified widespread increases in scarlet fever notifications in February 2014, beyond those seasonally expected. A total of 868 notifications of scarlet fever with onset dates during weeks 5 to 8 of 2014 were made to Public Health England (PHE) compared to an average of 444 for the same period over the past four years (range: 365 to 591; figure 1). These are the highest notification totals for this time of year since 1990.
The increase has been seen across England with regional totals for weeks 5 to 8 of 2014 (compared to 2013) as follows: 99 in the East of England (81 for same period in 2013), 74 in East Midlands (30), 92 in London (45), 67 in the North East (53), 179 in the South East (101), 109 in the South West (46), 62 in the West Midlands (32) and 108 in Yorkshire and Humber (95). The only region where fewer notifications have been made in weeks 5 to 8 in 2014 is the North West region with 78 notifications compared with 108 in weeks 5 to 8 of 2013.
Invasive Group A streptococcusA total of 106 invasive GAS (iGAS) isolates, defined as isolation of GAS from a normally sterile site, were referred to the Respiratory and Vaccine Preventable Bacteria Reference Unit at Colindale PHE from laboratories in England, Wales and Northern Ireland for specimens taken between weeks 5 and 8 2014, a slight reduction on the average (125 reports) but with the range (101-160 reports) for the same period in the previous five years (figure 2).
Three English regions have referred slightly higher than average (2009 to 2013) iGAS isolates for February 2014, North East (12 isolates), London (18 isolates) and the North West (21 isolates). All other regions in England are referring lower numbers of isolates than normal for this time of year.
Antimicrobial susceptibility results from routine iGAS laboratory reports for January indicate erythromycin non-susceptibility is at 5%, which is within the usual range. The susceptibility testing of iGAS isolates against other key antimicrobials (tetracycline, clindamycin and penicillin) indicate no changes in resistance being observed. There have been no reports of penicillin resistance in iGAS isolates in England to date.
The good news here is that, unlike in Hong Kong in 2012, only about 5% of the strep cases tested have shown resistance to erythromycin.
The PHE recommends:
Clinicians, microbiologists and HPTs should be mindful of potential increases in invasive disease and maintain a high index of suspicion in relevant patients as early recognition and prompt initiation of specific and supportive therapy for patients with iGAS infection can be life-saving.
If history is any guide, we should begin to see the number of scarlet fever/iGAS cases in England begin to decline over the next 6 to 8 weeks.