‘In some societies, the act of grooming for nits is deemed a perfectly acceptable social activity and why not? One Asian mother I spoke to at nursery said she had happy memories of cracking the nits in her dad’s hair. Another mother said she derives immense pleasure from sliding the live nits off her children’s hair with her nail tips and then trying to elicit the “little snap” from each one.’
Theresa, Croydon
‘On occasion, I have been asked to check my friends’ heads over a glass of wine in the kitchen. It is a necessity and we always have a laugh about it. After all, if you have kids you are going to catch nits at some time or another, but how can you check the back of your own head?’
Helen, Croydon
A piece of advice if your children are about to begin primary school 
make sure you always have a nit comb and tissues. But no matter how prepared you are, the first time your child gets nits is always a surprise. If it happens, remember that you are not a bad parent. Infestation is an inevitable part of growing up. If we arm ourselves with the facts, then we can deal with the problem once we get over the shock of it.
Head lice like heads. Whether they are clean or dirty heads – lice don’t have a preference. While it is true they flourish in the warm, moist conditions on the scalp, they also require pretty precise temperature and humidity to survive. You can make life nigh on impossible for lice to proliferate by the simple act of combing with a fine-toothed comb once a week.
Nits and lice cannot be ‘washed off’ with water, nor can they be drowned. Occasionally a live louse may get brushed out, but you can keep your hair as clean and tidy as you like and it will not keep the critters away. Washing your hair once a day or once a year makes no difference.
The current resurgence we appear to be experiencing has everything to do with our notions of our own hygiene – ‘it can’t happen to us!’ – and our expectations of the efficacy of over-the-counter products once infestation does occur. While there is some reliable historical data showing that head lice infestation was once more common among the poor because they were forced to share beds and live in squalid conditions, there is also most definitely a case for arguing that once upon a time families were more skilled at recognising symptoms and treating them because they had no recourse to a pharmacist or doctor.
Our reluctance to use routine grooming as a preventative measure – despite our desire to rid ourselves of unclean beasts – is evident in the amount we spend in the chemist on anti-louse shampoos in the hope of an instant cure.
It makes sense to keep haircuts short, manageable and tangle-free – especially in school-age children – so that when infestation occurs, you are not tearing out your hair (or indeed theirs) in your attempts to deal with it.
Lice are very particular about where they lay their eggs. An adult female louse lays just a few eggs (perhaps only 55 60 in her short lifetime), but each one is laid with deliberate care and attention.
A human head louse lays each egg somewhere warm and moist. This is usually right at the very base of a human hair, hard up against the scalp. The loving mother louse sticks it in place with a tough, quick-setting glue that forms a tight sheath around the hair shaft. This special glue is one of the secrets of louse success.
The glue is made in glands inside the louse’s abdomen. Like that other important insect secretion, silk, it is squeezed out as a liquid, but quickly hardens on contact with air. The female louse has two special appendages (‘gonopods’) on her tail to smear and wrap the glue around the hair stalk.
This egg cement has spawned plenty of research projects. Technically, it is ‘composed of four bands of protein, possibly cross-linked to aliphatic components with a tertiary structure of beta sheeting’. In other words, it is a highly complex compound, and very similar in its chemical make-up to human hair.
This is good news for the louse, because it means that the glue attaching the egg grips extremely tightly to the hair stand. It’s bad news for the pharmaceutical companies trying to develop nit-removing shampoos, though. It means that chemicals likely to break down the cement also attack and break down human hair. So far, none of these supposed nit-loosening lotions show any such signs of success.
The Life of a Louse
A drama in three acts
ACT I The Hair of the Head – A Simple Place But Warm and Cosy
ACT II The Infestation – It’s Getting Mighty Crowded
ACT III The Denouement
Cue: dramatic sweeping music
Lice, nymphs and nits exit stage left, pursued by comb
Head lice spend a lot of time having sex. Female insects usually have a sperm-storage organ (spermathaeca), and one mating is often enough to fertilise all the eggs they will lay in their entire lives. But in head lice, the part of the reproductive tract that ought to be a spermathaeca is so small its existence was long denied by louse researchers. One or two fertile eggs are laid after each mating; rarely three, never four. Anyway, they spend a lot of time at it. To save time, they usually feed while mating.
Eggs (nits) are laid at a rate of about 6–10 a day, mostly at night. The eggs start to hatch in around seven to nine days. Lice do not go through a magical metamorphosis like caterpillar to butterfly; instead, the baby louseling, the nymph, is already a miniature version of the adult. It starts feeding immediately. The newly hatched lice are about 1mm long roughly the size of the commas on this page. They are a devil of a job to spot.
After two days (about 10 blood meals), the louse nymph outgrows its skin, which splits open and is cast off. It will shed its skin twice more before reaching adulthood; the whole process takes about 10 days.
The empty skins discarded by the moulting lice are whisper-thin but they retain the size and exact shape of the louse down to the last claw, like a louse ‘ghost’. In very heavy infestations, these empty skins can be seen on our shoulders or pillows. It is these which probably gave rise to the myths about ‘wind-blown transfer’ or contamination via hats and hair-bands.
One generation of head lice takes just two or three weeks to change from newly deposited nit to sexually hyperactive adult 
DID YOU KNOW?
Aristotle had nits. Or his children did. Or his pupils, maybe.
Anyway, he knew they were produced by head lice, but he wasn’t quite sure exactly what they were.
He thought that head lice appeared, spontaneously, from the scalp (something to do with the reaction of the skin and the moisture within).
He thought that nits were the ‘imperfect’ offspring of the lice.
He thought this because he knew that nothing ever hatched from nits.
That’s because they had already hatched DUMBO
Nits are empty eggshells. It’s the live head lice you need to look for. The trouble is that nits are very obvious, and lice are not. When the eggs were laid, they were a dull grey, and they blended in perfectly against the scalp. Now they are empty, bright white and stand out like beacons.
Nits can remain attached to hair strands for months. We have that excellent nit glue to thank for that, and there they remain – as obvious as ever, until we do something about it.
As the hair grows, the nits move further away from the scalp. Human hair grows about 13mm per month. So four months after they were laid, the nits will be about 50mm along the hair. This also gives the impression that head lice live up in the thick hair. But head lice live on the scalp; this is the place, after all, from which the blood is sucked.
Nits’ brilliant whiteness is no accident. While the lice can hide safely, scurrying about on the scalp and hidden under the hair thatch, the nits now become the perfect target for any grooming. They are so easy to see that they divert attention away from the lice at play beneath them.
But, they can also linger on long after the lice that laid them have been combed away. It suddenly becomes clear that a ‘no nits’ policy in schools is pointless. Nits are empty eggshells. They are left over even after the head lice may have been removed. The living head lice are the things that bite, that itch and that move about from head to head.
Look for living lice