The mere mention of head lice can get people scratching their heads, and not just as a symptom of head lice! There are a myriad of myths surrounding these pesky little critters and it can often be difficult to sort out the fact from the fiction.
In this article we aim to challenge 22 myths and misconceptions and set the record straight around head lice.
Head lice are tiny wingless, six-legged insects1 - as a result they cannot fly. The six legs are also not very good for jumping. However, their legs end in hook-like claws, which makes them perfect for holding onto hair.2 As head lice cannot fly or jump from person to person, they can only be spread by direct head-to-head contact as the head lice crawl from one head to another. This is why kids putting their head together while playing is a common way to spread head lice.3
Imagine receiving a letter from the school to make you aware that someone in your child’s class had head lice… Does your mind fill with thoughts of yet another round of battle with head lice. You might be thinking it is only a matter of time before you are going to be going through your own child’s hair catching these contagious critters. Well luckily it is not as easy as you think to catch head lice. As head lice need close head to head contact to spread, transmission can be prevented through precautions such as not sharing personal items and avoiding close contact.3
Many schools used to have ‘no-nit’ policies which required a child to have all head lice, dead or alive, removed before a child returned to school.4 These policies have been eradicated due to the lack of evidence around transmission in schools, and the damage to mental health through shame and stigma.4 Therefore, isolation of a child who has head lice or keeping them out of school is not necessary.5 Instead follow simple back to school head lice advice.
Long gone are the days of the ‘nit-nurse’ and in the UK there are very few schools who conduct classroom checks for head lice. However, there remains a common perception that the spread of lice would be limited if we brought back classroom checks or the ‘nit-nurse’. Studies have shown that school screenings are not an accurate way of assessing or predicting which children are or will become infested, and such screenings have not been proven to have a significant effect on the incidence of head lice in a school. 4 Hence, we no longer need classroom checks or nit nurses.
The people most commonly affected by head lice is usually children between the ages 4-11 ,2 but does this mean that they caught them at school? Surprisingly, schools rarely present an opportunity for close head-to-head contact to enable transmission, except for nurseries or pre-schools.4 In reality, the likelihood is that head lice are a community health issue that is brought into the school.4 Although there appears to be a spike in head lice cases, usually at the start of school terms, studies show that the inflated number of cases is more likely to do with the extended time in the community while the kids are off for their school break.4
Do head lice prefer dirty hair or clean hair? Realistically, a head louse has only one preference and that is for a warm human host. Catching head lice has nothing to do with dirty or clean hair,2,5 and washing your hair will not rid you of head lice or nits. A head louse can expertly cling to the hair follicles during washing and the nit eggs are glued to the hair shaft.
Although there is evidence that head lice are more common in children with long hair, this has nothing to do with the preference of the head louse, but that transmission may be made easier with long hair.2 Head louse does not care whether that hair is long, short, clean or dirty; a head louse just wants a warm scalp it can feed and breed on.3
An itch is not the most reliable symptom of a head lice infestation, especially if it is the first encounter with head lice.1 Itching only occurs if the person affected becomes sensitised to the lice saliva. This sensitisation can take 4 to 6 weeks.1 This means you could go 4 to 6 weeks without an itchy head and potentially wouldn’t even know you had an infestation. Not everyone gets sensitised to the lice saliva and will never itch.1 Therefore, the diagnosis of an infestation can only be confirmed when you find a live louse.1
Only a live louse can indicate an active infestation of head lice.1 Nits are simply the empty shells of hatched louse eggs, and are often confused with dandruff. As a result, the presence of nits only indicates a past infestation that may or may not be currently active.1 But, what do head lice look like? Adult lice are about the size of a sesame seed and can move quickly. This can make them difficult to detect.1 It can help to know their favourite places to hide, which is usually where they lay their eggs. These hotspots include the nape of the neck, temples and behind the ears.6
Thankfully, there is no evidence to suggest head lice transmit infectious diseases, unlike other blood-sucking parasites like ticks, fleas, and mosquitos.1 They may be annoying and irritating little creatures, but they are not dangerous.4
For some people there is the belief that in order to eliminate these pests you must also treat the house as well as the person. Head lice and nits cannot survive very long without living on a human host, therefore there is no need to treat bedding, furniture, carpets or clothes. To survive, head lice need to feed on blood several times a day; without blood a head louse will die within 1-2 days.7 Eggs can survive a little longer away from its human host. Sometimes for up to 3 days, however, they need the warmth of being close to the scalp to hatch.1 So, the chances are your favourite pillow is safe.
Head lice are very specific to humans. Therefore, you cannot catch head lice from pets and pets cannot catch head lice from humans.4
The term 'nits' is often used to describe eggs lice lay. However, nits are technically the empty shells of hatched louse eggs that turn white and remain attached to the hair, but further from the scalp surface.2 If you have treated head lice and all that remains are empty nit shells glued to the hair shaft, then there is nothing to be concerned about as they will eventually grow out and fall off the head on their own. This may be why not all over the counter treatments come with complementary fine-toothed combs.
Household members and close contacts should be checked if someone in the house has been found to have head lice, but only treat those who actually have lice present.2 If there is more than one person in the house found to have live louse, it is advisable to treat all affected members of the same household together.2 It is important to treat anyone in the household, where a living louse has been found, on the same day as it helps reduce the risk of re-infestation.2 For more detail see our advice on what to do next once you discover a head lice infestation.
Newer insecticide-free treatments contain active ingredients which have a physical mode of action.2 They kill head lice and nits by physically coating their surfaces which cause them to suffocate and dehydrate.2 Due to this physical mode of action, resistance is unlikely to develop.2
Treatments are no longer restricted to older insecticide lotions or sprays which needed to be in contact with head lice for several hours to be effective. Head lice treatments have evolved and are now available in a variety of formats to suit the needs of different families and different hair types and lengths, such as head lice treatment shampoos, sprays, and mousse.
Treatment shampoos are an effective, fast-acting option for busy parents. If a previous treatment has not worked, it is worthwhile considering if enough treatment has been applied for long enough before assuming the treatment did not work. It is also worthwhile ruling out the possibility that a re-infestation occurred from someone else in the household or close contacts.
These days it is very rare for a GP to write a prescription for treatment since so many effective products are available and affordable at local pharmacies. In fact, some areas of the country have prohibited the prescribing of head lice products.8
The recommended directions of use for older insecticide treatments used to be two applications since they were not as effective at killing lice eggs. The treatments were applied one week apart due to the nature of the head lice life cycle. It takes approximately seven days for lice eggs to hatch, hence the treatment would target the newly hatched lice. However, these days there are insecticide free treatments that have been proven to be effective in only one application.
It is understandable that parents and guardians want to protect their children’s delicate skin. Rest assured that there are sensitive head lice treatments available over the counter specially tested for safety on children’s skin, just ask your pharmacist.
Sometimes reports on social media and chatter at the school gate create confusion. Of course, it would be much easier if parents could reach for something in the kitchen cupboard. Unfortunately, most home remedies simply don’t work. Home remedies identified that have been shown to be ineffective are mayonnaise, essential oils and hair straighteners. Be wary of any natural products that are untested in treating head lice.
Thankfully, these pesky little parasites do not live very long, especially when they don’t have a human host to feed from. Head lice cannot survive longer than one to two days without feeding, and their average lifespan is 30 to 40 days.2 The detection and treatment of head lice is fraught with misinformation, myths, and mismanagement.4 We hope this article has managed to demystify some common myths and support effective detection and management. Lyclear offers a wide range of effective head lice treatments that are clinically proven to kill head lice and eggs – so you can choose the best treatment options for you and your family. If you need more support, the most accessible healthcare professional you can talk to about head lice is in your local pharmacy.