Scabies may play role in later developing rheumatic fever, new research shows Friday, 16 February 2018

Source: Stuff, 16 February 2018

Children who have had scabies are 23 times more likely to develop rheumatic fever than children who haven't, new research shows. 

The research, published in the Journal of Paediatrics and Health on Thursday, found the risk factors for scabies, rheumatic fever and chronic rheumatic heart disease are "strongly associated". 

Joint research from the Auckland Regional Public Health Service, University of Auckland and AUT highlighted the importance of treating scabies as a preventative measure, researcher Simon Thornley said. 

Scabies is an itchy rash caused by microscopic parasitic mites that burrow under the skin. 

It, like rheumatic fever, is a disease associated with poverty.

Dr Simon Thornley said the research highlighted the need to identify and treat scabies early on - in order to possibly prevent the development of rheumatic fever or chronic rheumatic heart disease at a later stage.

High numbers of cases are reported among young Māori and Pacific Island children - the same groups most affected by rheumatic fever, public health physician Thornley said. 

The study looked at health records of more than 200,000 Auckland children aged three to 12 who attended an oral health service for the first time between May 2007 and October 2014. 

Some of these children had previously had scabies, while others had not. None had previously had rheumatic fever. 

Within five years of their scabies diagnosis, 440 were diagnosed with either rheumatic fever or chronic rheumatic heart disease. 

The findings showed children who had scabies were 23 times more likely to develop rheumatic fever than children who had not. 

Animal studies have shown pigs infected with scabies developed skin infections Staphylococcus aureus and Streptococcal pyogenes. 

The latter is strep throat, a common cause of rheumatic fever.

Most strep throats get better.

However, in a small number of people - mostly children - an untreated strep throat develops into rheumatic fever, where their heart, joints, brain and skin become inflamed and swollen.

The risk of getting rheumatic fever gets higher when someone has repeated untreated strep throat infections.  

While the symptoms of rheumatic fever may disappear on their own, the inflammation from even one rheumatic fever attack could develop into rheumatic heart disease, where there is scarring of the heart valves. 

Children in south Auckland were disproportionately affected by both scabies and rheumatic fever, Thornley said. 

Treatment and prevention of rheumatic fever has been targeted at swabbing and treating the throat as a result, but this research has "stepped a level back," to find why these infections occur in the first place, he said. 

He said while hospital diagnoses of scabies are rare and tricky to diagnose, it is easily preventable.

"The fact that it is one of the simplest diseases in medicine to treat raises the issue: if we did more to treat scabies maybe we wouldn't see these high numbers of rheumatic fever." 

Those diagnosed with scabies also later presented with cellulitis, dermatitis, impetigo and asthma. 

Thornley said he hopes the research will encourage healthcare providers to not overlook scabies, given the link between it and rheumatic fever. 

Roger Marshall, Paul Jarrett, Gerhard Sundborn, Edwin Reynolds and Grant Schofield co-authored the paper.