Tic Development Not Associated With Strep in Children of Parents With Chronic Tic Disorders

A study published in Neurology found there was no link between a strep throat infection and the development of tics in children who have a parent or sibling with a chronic tic disorder.

In the study, 24% of the children (n=61) developed tics. At 2-year follow up assessments, 7 more children had developed tics, with no found association between tics and strep. Female children had a 60% lower risk of developing tics than male children, which is similar to the findings of previous studies, independent of strep.

“There has been much debate about whether the bacteria that causes strep throat, group A streptococcus, plays a role in the development of tic disorders, with previous research providing mixed results,” said study author Anette Eleonore Schrag, MD, PhD, of University College London in the United Kingdom. “Our research looked at a population of children at a higher risk of developing tics due to having a first-degree relative with a tic disorder and did not find an association between exposure to strep and the development of tics.”
 
Schrag said, “Future studies are needed to investigate whether pathogens other than strep, or other factors that affect the immune system, play a specific role in the development of tics.”

The study involved 259 participants, ages 3 to 10, who did not have tics but had a parent or sibling diagnosed with chronic tic disorder. These children were tested for strep infection at the start and throughout the study, used with throat swabs, blood tests to detect antibodies that indicate a strep infection, or a combination of these tests.

The participants were followed for an average of 1.6 years, with alternating medical evaluations either in person or over the phone every 2 months. Parents of the participants kept a weekly diary and were told to report any possible sign of tics in their child as soon as possible.