Except it isn't. Head lice, widely thought to be an almost universal affliction of the pre-teens, are far less common than believed. We parents have spent needless hours wet-combing and shampooing our children, schools have fostered unnecessary alarm by issuing repeated "alert" letters, and many GPs, nurses and pharmacists have been handing out the wrong advice.
My authority for this remarkable claim is a report from the Public Health Medicine Environmental Group, which is the national professional association for consultants in communicable medicine - the medical officers covering every health district in the UK who are responsible for the prevention and control of disease.
Their report is the most comprehensive independent investigation into the control of head lice and has been produced by experts with impeccable credentials. It comes as something of a shock to discover, as a health reporter, that what you thought you knew was far wide of the mark and worse, as a parent, that what you did to your children may not have been in their best interests.
I have served my time by the bathtub, applying lotions with the scent of crude oil to my children's heads. With my youngest daughter, we gave up on the shampoos because the infection recurred so regularly, as we thought, and switched to wet-combing to remove the lice. Now I learn the infections were probably imagined, the shampooing probably unnecessary and the combing useless.
The experts say head lice are more a social than an infectious disease in the UK. They are hard to catch and rarely passed on in the classroom.
Most parents confuse head lice with nits, the pearly white eggs they lay which cling to the hairs. The only certain way to tell if your child is infected (no matter how many nits are present) is to find a living louse.
The best of way of dealing with an infection is to use a licensed shampoo - but only when an active infection has been found. Overuse of the shampoos can cause dermatitis and is anyway useless when there are no living lice present. The best way of detecting them is by wet-combing, but this is hopeless at eliminating them. Of such small advances in understanding is medical progress made.
The advice to head teachers is uncompromising. "Do not send out alert letters, do not exclude children with head lice, do not support any mass action, including wet-combing and do not agree with angry parents that routine head inspections should be re-introduced. They were never effective." It adds: "You may worsen the problem in your school if you are under the same misapprehensions as many of your parents."
Readers who wish to learn more can find the full report on the Internet at www.fam-english.demon.co.ukReuse content