Miss Francine Smith (name and details of patient altered to protect patient confidentiality), a 46-year old woman with a history of mental health problems and harmful alcohol use was admitted to a ward. Miss Smith had been homeless prior to admission. On admission, a head lice infestation was suspected. People who are homeless are at greater risk of infections than the general public as they are often in poor health and have difficulty maintaining hygiene (Fazel et al, 2014: Raoult et al, 2001). This article and its accompanying case study, outlines how head lice infection is diagnosed and treated, to illustrate possible issues in treatment and how these can be managed.
What are head lice?
Head lice (Pediculus humanus capitis) are tiny parasitic insects that infest the hairs of the human head and feed on blood from the scalp. Female head lice lay eggs near the scalp. These eggs are attached to the hair with a glue-like substance and take about a week to hatch, leaving behind empty, white egg cases called nits. Head lice infestation is known as pediculosis capitis (National Institute for Health and Care Excellence (NICE), 2021).
An adult head louse is around 3 mm long, the size of a sesame seed or a strawberry seed. Head lice do not jump or fly. They are usually picked up by head–to–head contact; it takes about 30 seconds for a single louse to transfer from one scalp to another. Less often, sharing hats, combs or pillows can spread them. Head lice live only on humans and die in a day or two away from the human scalp. They cannot be caught from animals (British Association of Dermatologists (BAD), 2021).
Normally a person with head lice has around 30 lice living on the scalp; however, in severe infections, there can be up to 1000 lice. Figure 1 illustrates the life cycle of a head louse.
Clinical features of head lice
The clinical features of a head lice infestation are: a history of an itchy scalp; scratch marks that may be visible on the scalp; the scalp that may look crusty; nits that may be visible close to the scalp; and the person may feel unwell.
Itching occurs because head lice have to feed on human blood several times a day. They obtain blood by biting the scalp. Bites and louse saliva can cause skin reactions and itching. Scratch marks may be visible because of the irritation caused by bites. Scratching can lead to a bacterial infection, impetigo and a crusty, weepy scalp. If the infection is severe, the person may feel unwell. Inspection of the scalp also shows eggs (nits); these are stuck to the hair near the scalp. They are the size of a pin head and are grey or brown. Empty egg cases are white and shiny and easier to spot. Immature lice are smaller than mature lice. All lice are difficult to spot on the head. You may see little red lumpy spots at the hair line. These are caused by a reaction to the lice feeding (BAD, 2021; Salhi, 2018). Figure 2 illustrates these clinical features.
Diagnosis of infestation
Head lice infestation is diagnosed by finding at least one live louse on visual inspection. Some clinicians use a bright light and a magnifying glass to find live lice; others use a fine-tooth comb (Jahnke et al, 2009; Gunning et al, 2019). It can be helpful to comb the lice onto a piece of white paper as this makes them more noticable. The lice may sometimes be trapped in the teeth of the comb so it is important to check that as well.
Treatment should not be given if live lice are not observed. Nits may remain on the hair for months, and dandruff and dirt can be confused as nits.
Treatment
NICE (2021) recommend either using a louse detection comb to physically remove the lice, wet combing or an insecticide. The author's personal preference is to use an insecticide.
Insecticides can be divided into two categories-those that kill lice by coating their surface and suffocating them and traditional insecticides that kill lice.
In the UK, Malathion 0.5% aqueous liquid (Derbac-M®) is the only chemical insecticide that is currently recommended. Side effects include angioedema; eye swelling; hypersensitivity and skin reactions. Resistance has also been reported (British National Formulary (BNF), 2022a).
Dimeticone 4% lotion is available as Hedrin 4% lotion by Thornton & Ross Ltd and Lyclear lotion by Omega Pharma Ltd. Side effects include alopecia; dyspnoea; eye irritation; hypersensitivity; scalp changes; and skin reactions. A spray solution is also available for the Hedrin 4% spray by Thornton & Ross Ltd. The lotion is applied to dry hair and scalp and allowed to dry naturally. It can be shampooed off after a minimum of 8 hours (BNF, 2022b).
Hair should not be dried with a hair dryer or exposed to open flames as there is a risk of serious burns as the products are flammable.
Wet combing with dimeticone 4% lotion is recommended as a first-line of treatment for pregnant or breastfeeding women, young children aged 6 months to 2 years and people with asthma or eczema.
One bottle of treatment is sufficient for hair up to shoulder length, but if hair is very long or very thick, an additional bottle may be required. A week after treatment, the hair should be treated again. A second treatment is required because the first treatment kills lice but not the eggs. Therefore, the second treatment is used to kill any lice that have hatched since the first treatment (NICE, 2021).
There is little research on which treatment is most effective. A study of primary school girls in Iran compared three treatments—permethrin, dimeticone and d-phenothrin. The cure rate was reported to be 100% with dimeticone, 63% for permethrin and 92% for d-phenothrin (Kalari et al, 2019). Of these three treatments, only dimeticone is used for head lice in the UK.
Challenges in Miss Smith's case
As discussed in the previous section, head lice are diagnosed by observing a live head louse. This is normally done using a fine-tooth or nit-comb to comb the lice out of the head.
Miss Smith's hair was so matted that it was not possible to get fingers through it. We began by applying a hair masque and leaving this on for an hour. The aim was to help soften the matted mass of hair and to enable us to detangle it. We then used Afro combs to detangle the hair. These are normally available with plastic, wooden or metal teeth. In my experience, plastic-toothed combs can break in very tangled hair and metal combs can rip out the hair. Hence, we used bamboo combs, and my colleague and I, each worked on one side of Miss Smith's hair to detangle it. It took us 2.5 hours to detangle her hair to almost shoulder length but there was a further 12.5 cm of hair to detangle. Miss Smith was getting very tired. We suggested cutting the remaining hair and she agreed. However, since her hair was too matted, it was not possible to cut it. Finally, we resorted to clippers, which got the job done.
We could now see Miss Smith's scalp and it was covered in plaque and crusts. It didn't appear infected and clinically appeared to be seborrhoeic dermatitis.
Bholah (2022) defines seborrhoeic dermatitis as:
‘…a common, chronic, or relapsing form of eczema that mainly affects the sebaceous gland-rich regions of the scalp, face and trunk.’
It is thought that seborrhoeic dermatitis is triggered by an overgrowth of a harmless yeast called malassezia that lives on the skin, or an over-reaction by the skin's immune system to this yeast. Treatment includes using medicated shampoo that contains ketoconazole, ciclopirox, selenium sulfide, zinc pyrithione, coal tar and salicylic acid. These can be used twice weekly for at least a month and if necessary, indefinitely (BAD, 2018). Two medicated shampoos are commonly used Neurogena T/Gel and Polytar (Neutrogena, 2022: Polytar, 2022). These contain coal tar and other ingredients to soften and lift plaques, reduce infection risks and sooth the scalp.
We applied water to Miss Smith's hair, massaged the shampoo into her scalp, covered her hair with a disposable shower cap and left it for 15 minutes. We then shampooed her hair and applied a deep conditioner. Medicated shampoo dries out the hair and we wanted our nit-comb to glide through her hair. Miss Smith's scalp improved with continued treatment.
When Miss Smith's hair had dried naturally, we used a fine-tooth comb to check for lice. We found several and were able to diagnose head lice.
Miss Smith had Dimeticone 4% lotion applied on her scalp that evening and then again a week later. Miss Smith was successfully treated for head lice. Prior to discharge, staff arranged for her to have support from the alcohol and social services, who helped her find accommodation.
Conclusion
Miss Smith was embarrassed to have head lice and to have matted, neglected hair. It was important to treat her with sensitivity and compassion. She responded positively to this form of treatment. Treating her hair, assisting her with bathing and providing her with clean clothes had a major impact on her mood and helped her get on the path to recovery.
Key points
- People who are homeless are at increased risk of infections due to health conditions and difficulty maintaining hygiene.
- It is essential to identify live headlice before beginning treatment
- When head lice lotions are applied the person must avoid naked flames and sources of ignition as the lotions are flammable
CPD reflective questions
- What clinical features might make you suspect that a person had head lice?
- How would you diagnose a head lice infection?
- What treatments are indicated in a person with eczema and why?