Head Lice Facts
The scientific name for a head louse is pediculus humanus capitis.
Head lice are found in people of all ages. Head lice are often seen as something that afflicts children. Although most commonly found in young children anyone with hair can catch them.
Head lice aren't particularly fussy. When I was young many decades ago the perceived wisdom of the day was that only people with dirty hair caught lice. By the time my daughter was born this had changed to lice prefer clean hair. Both of these statements are false. Head lice like scalps with hair on them, they don't actually have a preference for either clean or dirty hair.
Head lice cannot jump or hop and they have no wings. This means you can't catch them by standing close to someone who has them. Your head needs to be in contact with an infected head for at least 30 seconds as that's how long it takes a head louse to move from one head to another. This is why girls are more likely to catch them as they huddle together more than boys.
Only a third of people develop an itchy scalp. That means that two thirds of those infected are virtually symptomless when it comes to a head lice. The unfortunate third are allergic to the bites (actually it's the saliva rather than the bite itself) and/or faeces of lice but even so they usually don't feel particularly itchy until there there's been a large number of bites or a substantial colony has built up. This can take several weeks.
Head lice cannot live on pets so don't look accusingly at poor Fido or Felix everytime they scratch.
Having long hair does not increase your chances of catching head lice. It's the head to head contact which is important.
Although not impossible you’re unlikely to become infected from using bedding or wearing a hat of someone who is infected. Any head louse that has fallen off a head is probably sick or dying and will be unable to re-attach itself.