Scabies and rheumatic fever strongly linked, Kiwi researchers find

Scabies - an itchy rash caused by a mite burrowing into the skin - is treated as a "trivial" disease in New Zealand but it is linked to rheumatic fever, researchers have found. Photo / 123RF

New Kiwi research has found strep throat may not be the only cause of rheumatic fever in children - it's also strongly linked to scabies infections.

Researchers analysed data from more than 200,000 New Zealand children, and found that those with scabies were 23 times more likely to develop rheumatic fever or chronic rheumatic heart disease.

The study, which was led by University of Auckland public health physician Dr Simon Thornley, has been published in the Journal of Pediatrics and Child Health.

Scabies is an itchy rash caused by a mite that burrows under the skin. It is transmitted by skin contact and sometimes through bedding or furnishing. Living in an overcrowded house increases the risk of getting scabies.

In New Zealand scabies infections are most common among Māori and Pacific Island children.

Acute rheumatic fever - a "third world illness" which can lead to heart disease and early death - is also far more prevalent in these groups.

Streptococcal throat infections are believed to be the key cause of rheumatic fever, with New Zealand efforts focusing on finding and treating strep throat cases quickly.

But there has been speculation scabies could also be behind some rheumatic fever cases. Scabies can lead to streptococcal cellulitis, and researchers now believe that could also lead to rheumatic fever.

In Australia, Aboriginal communities have high rates of rheumatic fever even though strep throat is rare - but there is a high rate of scabies. A 1978 paper also found an outbreak of scabies in Trinidad was closely followed by a spike in rheumatic fever cases.

New Zealand efforts to prevent rheumatic fever have focused on detecting cases of group A streptococcus infection through throat swabbing. File photo / Doug Sherring

Thornley and his co-authors analysed data from the Auckland Regional Dental Service and hospital diagnoses to measure how closely scabies, acute rheumatic fever and chronic rheumatic heart disease were linked.

Children who had been diagnosed with scabies were 23 times more likely to develop rheumatic fever or chronic rheumatic heart disease, they found.

After adjusting for ethnicity, scabies sufferers were still eight times more likely to get rheumatic fever or rheumatic heart disease, Thornley said.

Scabies treatment is by a prescription cream or a tablet. The entire family needs to be treated at the same time as the mites will quickly return, especially in crowded homes or if a high number of local children have scabies.

Research led by Dr Simon Thornley has found children with scabies are 23 times more likely to get rheumatic fever or chronic rheumatic heart disease. Photo / Supplied

Thornley hoped the research would see scabies taken more seriously in New Zealand.

"Scabies is probably the most easily treatable infectious disease that we know of," he said.

"In some parts of the world scabies is a notifiable disease - in Denmark and Belgium, they take it very seriously. But in New Zealand it's just considered a trivial disease."