Eggs from head lice are notoriously difficult to remove because the female lice lay them directly onto strands of hair and cement them in place with a glue-like substance.
They are so well attached to the hairs that they can stay in place even after hair has been treated with pediculicides – substances used to kill lice.
Now, new research, published in the Journal of Medical Entomology, suggests people who pay for these products are wasting their money as the eggs can be removed equally effectively using conditioner.
The news comes just after an expert claimed that selfies are causing an epidemic of lice in teenagers.
Marcy McQuillan, a lice-treatment expert who runs two lice-treatment centers in California, says she has seen a dramatic rise in the incidence of lice among young people.
She maintains it is due to teenagers bumping heads to take selfie photos.
In this study,scientists in Belgium gathered 605 hairs from six different children. Each hair had a single egg attached to it.
Of these eggshells, 14 per cent contained a dead egg and the rest were empty, having already hatched.
The researchers tried to remove the eggs and tested the amount of force needed to do so.
They found that nits on the hairs that were left completely untreated were the most difficult to remove.
Eggs on hairs that had been soaked in deionized water were much easier to remove, as were the eggs on hairs that had been treated with ordinary hair conditioner and with products specifically marketed for the purpose of nit removal.
However, the researchers found no significant differences between the ordinary conditioners and the special nit-removal products.
In all cases, less force was required to remove the nits after the hair had been treated, but the effectiveness of the products was essentially the same.
‘There were no significant differences in measured forces between the ordinary conditioner and the commercial nit removal product,’ the authors wrote.
‘The commercial nit removal products tested in the current study do not seem to have an additional effect.’
The authors hypothesise that the deionized water was effective because it acts as a lubricant, so less friction is needed to remove the nits from the hairs. The same goes for the conditioners.
‘Treatment with conditioner reduces the coefficient of friction of undamaged and damaged hair,’ they write. ‘As a consequence, conditioners will facilitate nit removal.’
While removing eggs is a vital part of treating head lice, and they are hardest thing to remove because they are glued to the hairs, just removing them is not enough to remove an infestation.
The lice themselves also have to be removed and, ideally, they need to be removed within seven days of hatching because, otherwise, they will start to lay more eggs.
‘Head lice are spread through head-to-head contact,’ Ms McQuillan added.
‘Lice don’t jump or fly, so you actually have to touch heads.
‘Every teen I’ve treated, I ask about selfies, and they admit that they are taking them every day.’