Over-zealous parents can be doing more harm than good if they blitz their children's hair with head lice treatment without inspecting it first.
The return to school this month means that many parents are receiving letters warning about the spread of 'nits'.
And the rise of selfies - which involve children crowding together to capture the perfect picture - is also contributing to the spread of lice from head to head.
The Irish Independent has learned that some schools have sent out letters to parents following head lice outbreaks just a week after they reopened their doors.
But pharmacists and GPs are warning parents against being over-reliant on chemical products, as head lice can mutate and actually become resistant to treatment.
Some parents use these shampoos as prevention methods, although they only work if the child actually has head lice.
The Irish Pharmacy Union (IPU) estimates that one in 10 schoolchildren suffer from head lice at any time, and that 80pc of infestations occur between the ages of four and 16.
However, there is a growing resilience among head lice when they are treated with over-the-counter products.
A study in Southern Illinois University found that the majority of lice in America are now resistant to shop-bought treatments, due to their over-use.
The report stated that lice in 25 out of 30 US states surveyed are now immune to chemical shampoos.
Dr Rukshan Goonewardena of the Irish College of General Practitioners (ICGP) insisted that parents should check their children's hair for lice before turning to treatments.
"Parents should not use chemical treatment for prevention of lice. This is of no benefit and can give rise to the emergence of lice that are resistant to the treatment," he said.
"Lice treatment should only be used if the diagnosis is confirmed."
Dr Goonewardena said head lice are not able to jump or fly from person to person, and can only spread through head-to-head contact.
He advised that children's hair should be combed daily, until no lice or eggs are found for two weeks.
"The hair can be moistened with conditioner to make the process easier, and the comb should be cleaned by wiping it with clean paper or a cloth after each pass," he said.
Dr Goonewardena added that once a case of head lice is detected, all people in the household should be examined to ensure they are not affected.
Social media is also being blamed for the rapid transmission of nits.
Several experts have warned that selfies are an ideal opportunity for lice to spread, as people put their heads together while posing.
California-based lice expert Mary McQuillan said: "I've seen a huge increase of lice in teenagers. Typically, it's younger children I treat, because they're at higher risk for head-to-head contact.
"But now, teens are sticking their heads together every day to take phone pictures.
"Every teen I've treated, I ask about selfies - and they admit that they are taking them every day. I think parents need to be aware, and teenagers need to be aware too."