Children can develop tics and compulsions associated with OCD after contracting infections like strep throat, experts are warning.

A common and painful infection for young children, strep throat is typically treated using antibiotics.

However, for a small number of patients it can cause bizarre behavioural disorders such as severe tantrums, obsessive-compulsive disorder (OCD) and even tics.

So, what is strep throat?

Otherwise known as ‘streptococcal pharyngitis’, the infection affects the back of the throat causing pain, swollen glands and discomfort when swallowing, and can be spread in droplets in coughs and sneezes, the NHS says.

But, while most people with a minor strep infection go on to make a full recovery, there is a small risk that it could cause a rare complication that attacks the brain.

One family affected by the condition revealed that their son, Brandon, who was five and a half at the time, suddenly changed, going from a happy-go-lucky kid to having extreme tantrums and exhibiting signs of debilitating OCD.

“It was almost psychotic,” Brandon’s mother, Bonnie Markowitz, told CBS New York.

Doctors say that the shift in the young boy’s behaviour was the result of a complication called PANDAS, which stands for Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections.

“What that basically means is a child gets an infection and the antibodies to that infection end up attacking the brain instead of the germs,” PANDAS expert Dr. Elizabeth Spaar told the news station.

Despite PANDAS being estimated to affect one in 200 children, the condition is often misdiagnosed and antibiotics are given as the standard form of treatment.

However, Spaar warns that for children who aren’t properly treated, “there can be lifelong effects from it.”

While many children have OCD, tantrums and tics, the tell-tale sign that they are suffering from PANDAS is the sudden and dramatic onset of symptoms in such a closely-related time frame to contracting strep.

“Patients with PANDAS have a very sudden onset or worsening of their symptoms, followed by a slow, gradual improvement.

If they get another strep infection, their symptoms suddenly worsen again,” according to the National Institute of Mental Health.

In most cases, children will get better with antibiotics but symptoms can take weeks to go away and many experience relapses.

If you are concerned or have persistent or severe symptoms of a strep A infection, the NHS suggest arranging an appointment to see your GP.