2017 HCHB_digital

Head Lice
Head lice (pediculosis capitis) are small, brownish-grey, wingless insects, about
the size of a sesame seed (2–3mm), which feed on blood from the scalp. They are
most common in children, but can also spread to adults.
Their stumpy legs make them incapable of jumping and they cannot fly,
instead they use their single claw and “opposing thumb” on their legs to
grasp the hair shaft and quickly crawl from head to head. Most are grey,
although some may look black and after feeding their body may take on a
reddish colour. They spread easily among people in close contact, such as
family members and school friends. Head lice only feed on human blood and
only infect the scalp – they are a different species to body lice and pubic
lice and in the natural environment will not interbreed. Unlike body lice,
they do not carry disease, and apart from a risk of secondary infection from
scratching, are unlikely to cause medical harm. Some experts regard head lice
as more of a cosmetic, rather than a medical, problem.
An itchy scalp is the most common symptom of head lice, caused by a delayed
allergic reaction to the lice’s saliva or faeces. This reaction may take between a week
and three months to develop which means that many customers may have been
infested for some time without knowing. Some people may not actually itch at all.
Female head lice can lay up to eight eggs per day. These egg cases are brown
and hard to see until the louse nymph hatches seven to 10 days later. By this time
the empty egg case has moved up the hair shaft as the hair has grown and now
appears white, so is much more easy to detect. When people talk about nits, they
are actually referring to the empty egg cases. The nit is stuck on the hair shaft
close to the scalp with a strong, highly insoluble cement which makes it hard to
get off, but easy to distinguish from flakey bits of skin, dried hairspray or dandruff.
Females may lay 50–100 eggs during their lifespan of around 30–40 days.
It takes about 10 days for a nymph to mature and be able to breed, and each
louse lives for about a month on the scalp, but for only 48 hours off it. Optimum
conditions and a moderate temperature and humidity are required for hatching
which explains why head lice are more prevalent over summer.
TREATMENT OPTIONS
Category Examples Comments
Egg removal products and
combs
Products to detect head lice
Products with a physical
action
Products with a neurological
action
Products with both a physical
and neurological action
(usually contain essential oils)
Preventive products
[GENERAL SALE] eg, NeutraLice Conditioner
Shampoo Lice Egg Remover*, Neutralice
Nitcomb, Parasidose Long Tooth Comb, Robi
Comb Pro
[GENERAL SALE] eg, Moov Combing
Conditioner for Head Lice Detection
[GENERAL SALE]
eg, benzyl alcohol 5% (eg, NeutraLice Advance
Lotion*) biococidine (eg, Parasidose Lice-Nits
Treatment), isopropyl myristate (eg, Moov Head
Lice Treatment Sensitive)
[GENERAL SALE]
eg, permethrin (Lice Clear*), d-Phenothrine
(Parasidose Extra-Strength Shampoo)
[GENERAL SALE]
eg, combination of essential oils (Moov Head
Lice Solution*, NeutraLice Natural Spray*, Nit-
Enz Organic)
eg, neem oil (Licener Single Treatment)
eg, anise oil, cinnamon leaf, citronella,
eucalyptus oil, geranium, lavender oil, mint,
tea-tree oil, thyme
[GENERAL SALE]
eg, Ladibugs Mint Spray, Moov Head Lice
Defence Spray, Nit-Enz Head Lice Repellant,
Parasidose Lice Repellant Spray
Egg removal products allow eggs to be brushed out easily from the hair. Fine metal-toothed
combs with rounded teeth are used to detect and remove head lice. Use on wet hair with
conditioner. Not usually 100% effective if used without treatment products. Electric combs
stun or kill lice and are used on dry hair. Hard to use on very thick and curly hair or on young
children.
Combing conditioners stun lice and help detect the presence of head lice and eggs.
These products do not kill lice or nits.
Benzyl alcohol suffocates lice by affecting their respiratory spiracles; dimeticone coats the
louse, disrupting its ability to manage air and water exchange across its body surface;
and isopropyl myristate kills lice by dehydrating them. Biococidine claims to suffocate
and dehydrate head lice; however, the actual active ingredient is undisclosed, making it
impossible to check for allergies. Some may be used in children as young as three months
and in pregnant women. Most are suitable for asthma sufferers.
Permethrin, phenothrin, and malathion are all neurological agents, each with a slightly
different mode of action, although the end result is usually paralysis of the louse, preventing
it from feeding. Resistance is common.
Products with both a neurological and physical effect include most products that contain
essential oils, including neem oil. Neem oil interferes with the growth and reproduction of
head lice, and also suffocates their eggs. Essential oils such as eucalyptus, tea tree, lavender,
and clove oil can also be toxic if misused, and strong evidence for their effectiveness at
killing head lice or their eggs is lacking, although combinations with vegetable oils may be
more effective.
Either contain essential oils that repel lice or coat the hair making it difficult for lice to attach.
Usually used every two to three days or weekly to keep lice from infesting hair. Will not treat
already established infestations.
Other products Air Alle (www.nitcrew.co.nz) Controlled heated air is directed onto dry hair by a trained technician. Process takes 30
minutes and effectively kills head lice and nits. May need to be repeated.
Products with an asterisk have a detailed listing in the Head Lice section of OTC Products, starting on page 243.
Page 90 HEALTHCARE HANDBOOK 2017-2018 Common Disorders