Current treatment options for head lice and scabies

Transcription

1 Drug review Current treatment options for head lice and scabies Maureen Connolly MRCPI, MRCGP Skyline Imaging Ltd Local resistance patterns and patient/parent preferences should be taken into account when prescribing for head lice and scabies. This Drug Review considers the current management options, followed by a review of prescription data, sources of further information and the Datafile. Head lice (Pediculus humanus capitis) are bloodsucking, wingless insects that live on the hairs of the head and feed on the scalp. The adult head louse is 3-4mm in length and grey white in colour. The female louse has a life-cycle of one month during which she can lay up to 7-10 eggs per day. The eggs are laid about 1cm from the scalp surface and are strongly bound to the individual hairs with a glue-like material (see Figure 1). The egg capsules are called nits and these empty shells are left cemented to the hair shaft once the louse hatches 8-10 days later. The presence of nits does not confirm infestation as nits can remain in the hair for weeks after successful eradication of the lice. Head lice mainly affect schoolchildren between the ages of 4 and 11 but can be found in any age, sex, race or social class. Head-to-head contact is the most common means of transmission, but spread may also occur through the sharing of hair brushes or accessories. 18 Prescriber 19 January

2 VM VM Figure 1. The presence of nits does not confirm head lice infestation as they can remain for weeks following eradication Patients can present with scalp itching or irritation, most commonly affecting the occipital or post auricular areas. Individuals usually present with less than 20 adult lice in the scalp but up to 5 per cent of patients can have more than 100 on presentation. Sometimes scalp excoriations become secondarily infected and cervical lymphadenopathy is found. Diagnosis is made by identification of adult lice and/or eggs seen attached to the hair. Head lice treatments Detection combing is the procedure in which wet hair is systematically combed to check for the presence of head lice and is an effective and reliable method to confirm head lice infestation as only live lice need to be treated. The choice of treatment depends on the preferences of the patient/parent and on the treatment history. Three types of treatments are available: insecticides, wet combing and dimeticone. Insecticides Worldwide resistance to several topical insecticides is growing, with head lice resistance to permethrin (Lyclear Creme Rinse) and malathion becoming an increasing problem throughout the UK. 1 There is no clear consensus as to what defines the best treatment for eradication of head lice 1 and thus management often depends on resistance patterns to various insecticides throughout different geographical areas. The Cochrane review similarly concluded that the best choice in the management of head lice would now depend on local resistance patterns 2 since the emergence of drug resistance. The rotational policy of insecticides on a district-wide basis is now considered outmoded and has been abandoned. Figure 2. Wet combing may be preferred by patients or parents who do not want to use insecticides In order to overcome the development of resistance, the BNF 3 recommends that a mosaic strategy is adopted whereby, if a course of treatment fails to cure, a different insecticide should be used on the next occasion. If treatment with either permethrin or phenothrin fails, then a non-pyrethroid parasiticidal should be used for the next course. Head lice infestation should be treated with a lotion or liquid formulation. Shampoos are best avoided as they are too diluted to be effective. Patients with eczema and asthma should be treated with aqueous rather than alcoholic preparations, so it is best to use a liquid in an aqueous base rather than a lotion in an alcoholic base for these patients. Patients should be made aware that the various myths regarding head lice should be dispelled. For example, the following statements are all untrue: head lice are only associated with dirty hair; only children can get head lice; an itchy scalp indicates infection; children should be kept away from school if infected; the remaining presence of nits or eggs still indicates active infestation; asymptomatic family members should be treated just in case ; or that lice can jump from one head to another. In fact, head lice can affect anyone s hair, are transferred by crawling from headto-head and only individuals with live lice should be treated. Pyrethroids Pyrethrin is a natural plant extract from the flower heads of Chrysanthemum cinerariaefolium. Pyrethrins are the active insecticidal component of pyrethrum. The synthetic pyrethroids phenothrin (Full Marks) and permethrin were launched in the UK in They can cause wheezing or dyspnoea in people with a known allergy to chrysanthemums, ragweed or related plants. Allergic contact dermatitis can also occur in some individuals. Prescriber 19 January

3 confirm the presence of live head lice in scalp and check all other family members for active infection choice of treatment depends on the preferences of the patient/ parent and on treatment history; 3 types of treatment are available wet combing insecticides dimeticone methodically comb wet hair with a fine-toothed comb to remove lice; hair conditioner may be used to facilitate the process; repeat every 4 days for at least 2 weeks and continued until no lice have been seen for 3 consecutive sessions use a topical liquid or lotion depending on the presence/absence of eczema/asthma in addition to head combing; the first-choice topical insecticide depends on local resistance patterns in the area; apply for 12 hours and repeat in 7 days if no improvement, use an alternative product, apply for 12 hours and repeat in 7 days apply dimeticone lotion all over scalp and include all the hair, leave on for 8 hours (or overnight) and wash off; repeat application after 7 days if no response/improvement, try wet combing or an insecticide if no improvement, consider trying dimeticone or an insecticide if still no improvement, use carbaryl liquid/lotion; apply for 12 hours and repeat in 7 days if still no improvement, try dimeticone or head combing and continue combing until head lice clear Figure 3. Recommended treatment of head lice Permethrin is a synthetic pyrethroid and was one of the first thermostable and photostable insecticides developed following the elucidation of the chemical structures of natural pyrethrins in It is more potent than its parent compound. Its insecticidal activity was 18 times greater than chlorophenothane (DDT). Permethrin is absorbed across the insect cuticle. It acts on the nerve cell membranes of the parasites causing disruption of the sodium channel current, delayed repolarisation and paralysis of the nerves in the exoskeletal muscle that allow lice to breathe. This causes the lice to suffocate. 5 Permethrin has exhibited very low mammalian toxicity. When applied topically less than 2 per cent is absorbed percutaneously and it is rapidly broken down, conjugated and excreted as inactive metabolites, primarily in the urine. Permethrin has residual activity and is supposed to remain on the hair for up to two weeks, but as it is not 100 per cent ovicidal two treatments one week apart are recommended to obtain higher cure rates. Unfortunately resistance to permethrin has developed throughout the UK with a failure rate as high as 87 per cent in one study. 5 Phenothrin, also a synthetic version of the natural pyrethrins, differs only slightly from permethrin in structure. 6 As phenothrin was one of the early synthetic pyrethroids, it still retains the heat and light instabilities of the natural pyrethrins and so a second 20 Prescriber 19 January

4 application is recommended a week later to kill lice that have hatched after the first treatment. 7 Resistance to phenothrin has also developed in recent years. However a study comparing two applications seven days apart of either 4 per cent dimeticone lotion (Hedrin) or 0.5 per cent phenotrin liquid showed a cure rate of 75 per cent and 70 per cent respectively. 8 Malathion In 1971 malathion was launched, heralding a subsequent decrease in the prevalence of head lice. 7 Malathion is an organophosphorous insecticide, which acts through cholinesterase inhibition. It irreversibly binds to and inhibits the function of acetylcholinesterase causing spastic paralysis and death. Malathion is considered safe in pregnancy and breastfeeding. Unfortunately widespread resistance has been reported throughout the UK 9,12 with one study quoting a 64 per cent failure rate. 1 Malathion can be used as a 0.5 per cent lotion (Prioderm) or more appropriately as a 0.5 per cent liquid in small children or in patients with a background history of asthma or eczema. Manufacturers recommend that it is applied to the dry hair and scalp, allowed to dry naturally and washed out after 12 hours. The treatment should be repeated one week later to kill any newly hatched lice. However, the lotion should not be used more than once a week for three consecutive weeks as the likelihood of head lice eradication is not increased. Carbaryl Carbaryl (Carylderm) is a carbamate and, like malathion, is a cholinesterase inhibitor. It is potentially carcinogenic in rodents and thus a potential human carcinogen, and so it has been restricted to prescription use in the UK. However the Department of Health has emphasised that this is only a theoretical risk and that any risk from the intermittent use of head lice preparations is likely to be exceedingly small. It is formulated as a 0.5 per cent alcoholic lotion and a 1 per cent liquid with a 12-hour application time. Ideally treatment should be repeated one week later to eradicate lice emerging from any eggs that survive the first treatment. In the UK there is still an overall good response to carbaryl but resistance is beginning to emerge in some areas. 10 Wet combing Bug-busting involves combing of wet hair with a finetoothed comb to remove all lice as they hatch, ensuring that none reach maturity to lay the next generation of eggs. In clinical studies bug-busting has 22 Prescriber 19 January 2008

5 VM reasonable to consider dimeticone as a first-line alternative to malathion, permethrin or phenothrin, particularly for parents or patients who did not want to use insecticides. 14 Alternative treatments Although several alternative treatments such as tea tree oil and aromatherapy oils have been used to treat head lice, there are no formal controlled clinical trials showing their efficacy, potential side-effects or toxicity and therefore they cannot be recommended as a treatment option for head lice. Figure 4. Permethrin is now the preferred treatment for scabies; it should be applied twice, one week apart shown variable cure rates from per cent after 14 days of treatment. 11,12 The recommended regimen is one wet combing session every four days for at least two weeks. If lice are found on the second, third or fourth wet combing session, wet combing should be continued until no lice have been seen for three consecutive sessions. Bug-busting can be used alone or in addition to a topical pediculocide and is particularly useful in cases where resistance has developed to all the topical agents. It is time-consuming and labour intensive, although it may be preferred by patients or parents who do not want to use any chemicals. Dimeticone Dimeticone 4 per cent lotion is a new treatment licensed for head lice. 13 It is a colourless and odourless fluid with a slightly oily texture that is applied to dry hair. It should be allowed to dry by evaporation without the use of hairdryers and should be washed off after eight hours. It is important that it is applied to all the hair and scalp. The manufacturer recommends that dimeticone is applied twice, seven days apart, in order to kill nymphal lice emerging from eggs that might not have been killed on the first application. Dimeticone works by a physical rather than a chemical mode of action and thus there is no evidence of resistance. 8 The dimeticone is in a silicone solvent that immobilises the lice and, as the solvent evaporates, the lice are left coated and subsequently die by reverse osmotic effects resulting from disruption of their ability to manage internal water. 13 A recent review by the Drug & Therapeutics Bulletin recommended that, based on current evidence, it was Scabies Scabies is a common skin condition caused by the mite Sarcoptes scabiei var hominis, an obligate human parasite that burrows downwards into the epidermis 15 and typically presents with a papular, intensely pruritic eruption usually involving the interdigital spaces and flexural creases. 5 Transmission is by close body contact and successful management requires treatment of the affected individual as well as close contacts. The incubation period for the first infestation is usually three to four weeks, but subsequent infections can provoke symptoms within a few days. The commonest presenting symptom is generalised pruritus, more intense at night and after a hot bath or shower. The lesions affect the interdigital web spaces of the hands, flexor surfaces of the wrists and elbows, axillae, ankles, feet, buttock areas, male genitalia and periareolar area in women. Young children and the elderly and immunocompromised can also have face and scalp involvement. Clinical presentation varies from erythematous papules with or without excoriations to vesicles, nodules, dermatitis or a secondary bacterial infection. Finding a burrow (which represents the tunnel that a female mite excavates while laying eggs) is pathognomonic for scabies, but even they can be absent. Confirmation of the diagnosis is obtained by taking a skin scraping from an affected area (ideally a burrow), placing the material on a glass slide with a drop of 10 per cent potassium hydroxide and seeing an adult mite, egg or eggshell under light microscopy. Crusted ( Norwegian ) scabies is a hyperinfestation presenting as hyperkeratotic warty crusts typically affecting the hands and feet, but all areas of skin including the scalp and trunk can be involved with patients harbouring up to millions of mites. Crusted scabies can easily become secondarily infected, present with generalised lymphadenopathy and be associated with a peripheral blood eosinophilia. 24 Prescriber 19 January

6 scabicide applied incorrectly, or missed parts of the skin nonadherence reinfestation, especially if all close contacts not treated simultaneously resistance to scabicide wrong diagnosis psychogenic itch secondary eczema mistaken for scabies sensitisation or allergic contact dermatitis to topical scabicide Table 1. Reasons for treatment failure in patients with scabies Crusted scabies usually occurs in patients with a compromised immune system (eg the elderly, transplant patients and HIV-positive individuals) as well as those with decreased sensory functions (eg paraplegics). It is highly contagious for medical and paramedical staff and is far more difficult to eradicate than classical scabies. Treatments The primary method of treatment for scabies is by topical application of a scabicide overnight to the whole body from head to toe, although oral treatment with ivermectin is an effective alternative in certain circumstances. 5 It is important to apply it to the entire skin surface except the eyes (despite manufacturers advice of applying it to the whole body except head and face), and this is particularly important in small children and the elderly who can have scalp involvement. 5 Patient information leaflets are useful as they explain the correct method of application, warn patients against overuse of products and explain to them that the itch can persist for a number of weeks even after successful treatment. It is important to treat all family members and close contacts simultaneously to avoid reinfestation. Bedclothes and clothing should be washed but do not require any special laundering such as dry cleaning. A Cochrane review 16 concluded that topical permethrin appeared to be the most effective treatment for scabies. Ivermectin (unlicensed) appeared to be an effective oral treatment, but they highlighted that more research was needed on the effectiveness of malathion, particularly when compared to permethrin. Benzyl benzoate Benzyl benzoate, an ester of benzoic acid and benzyl alcohol, was originally isolated from natural products such as balsam of Peru and has been used to eradicate scabies for over 60 years. Various treatment regimens have been employed but two to three applications on consecutive days has been recommended by the BNF. 3 The main side-effect of benzyl benzoate is skin irritation, usually developing within minutes of application and in some cases so severe that it needs to be washed off again immediately to ease the irritation. Its use in children is not recommended as the dilution necessary to reduce its irritant effect on children may also reduce its efficacy. Permethrin Permethrin is now considered the treatment of choice in the UK, USA and Australia. 5 It is well tolerated, has low toxicity and is poorly absorbed across the skin. The small percentage that is absorbed is rapidly metabolised. It is ideally applied overnight for an eight-hour period and then washed off. The BNF 3 recommends that permethrin should be applied twice, one week apart in ordinary scabies to increase its effectiveness, but patients with crusted Norwegian scabies may require two or three applications on consecutive days to ensure that enough penetrates the hyperkeratotic areas to kill all the mites. It is licensed in children under medical supervision from two months upwards. It has not been tested in pregnancy but has been used with no apparent illeffects. Malathion Malathion 0.5 per cent has also been licensed for use in scabies, with the manufacturer recommending that it be applied to the whole body and left on for 24 hours. However, as there are no randomised controlled trials showing its efficacy in the management of scabies, the Cochrane study recommends permethrin as the first-line agent in the management of scabies. 16 Ivermectin Ivermectin acts by blocking neurotransmission across nerve synapses that use glutamate or gamma-aminobutyric acid (GABA) as their neurotransmitters. It should not be used in pregnancy, breast-feeding mothers or in children under five years or 15kg. This is a broad-spectrum anthelmintic agent structurally similar to the macrolide antibiotics but without antibacterial properties. 5 It is an antiparasitic agent and effectively used in onchocerciasis, strongyloidiasis and cutaneous larva migrans. Although unlicensed in scabies, it has been successfully used on a named-patient basis for crusted Norwegian scabies in doses up to 200mg per kg. As ivermectin is not ovicidal, a second dose after 7-12 days may be necessary. 17 Crotamiton Crotamiton cream (Eurax) has also been used in scabies as an alternative scabicide. It is 26 Prescriber 19 January

7 formulated as a 10 per cent lotion or cream. It requires nightly treatments for three to five days and can cause skin irritation. It has been helpful for relieving postscabetic itch after treatment. Associated and postscabetic itch This can be managed by the use of emollients, mildto-moderate topical steroids or crotamiton 10 per cent cream on its own or in combination with a mild topical steroid ointment (Eurax-Hydrocortisone). In addition sedative antihistamines can also be helpful in relieving the itch associated with scabies. Management of scabies in nursing homes An outbreak of scabies in a nursing home should be dealt with quickly and efficiently in order to keep the outbreak to a minimum. All staff, patients and relatives of staff and patients should be treated with permethrin ideally as soon as possible but within a two-week period in order to prevent reinfestation. All staff with patient contact should be treated. Where there are clinical features or history suggestive of scabies in a staff member or resident, the family members or others with close contact should be treated. All other residents with contact or shared space with the affected individuals (staff or residents) should also be treated. Ideally, all treatments should be undertaken within 24 hours of each other to prevent re-infection through cross contact. Judgement may be needed with different situations and the help of local public health physicians or dermatologists can be helpful. Nursing homes should have a scabies protocol that has been approved by the local public health department that can be consulted if an outbreak occurs. Conclusion There are no published guidelines for the management of scabies or head lice and the factors affecting prescribing should depend on the resistance pattern in a certain geographical area. For head lice the choice of treatment should depend on the preferences of the individual/parent and on the treatment history. Unfortunately factors like cost and familiarity may be considered rather than what might be the most appropriate agent for the patient. Patient education is vital to ensure the product is correctly applied as incorrect usage may lead to a greater problem with resistance. References 1. Downs AM, Stafford KA, Harvey I, et al. Evidence for double resistance to permethrin and malathion in head lice. Br treat suspected or confirmed case and treat all close contacts at the same time for standard scabies apply permethrin all over the skin except scalp, leave on for 8 hours (ideally overnight) and then wash off reapply the cream to any areas during the 8-hour period in the elderly, immunocompromised patients or young children, the scalp in addition to the rest of the skin should be treated repeat the treatment in 1 week (particularly important if not all the skin was treated on the first application) patients can continue to be itchy for a few weeks after eradication of scabies and this is not due to treatment failure; the itch can be eased with topical emollients, crotamiton cream 10% and/or sedative antihistamines for treatment failure use an alternative scabicide or consider ivermectin treatment Figure 5. Recommended treatment of scabies J Dermatol 1999;141: Dodd CS. Interventions for treating head lice (Cochrane Review). In: The Cochrane Library, Issue 3, Parasiticidal preparations. British National Formulary 2007; 53: Burkhart CG, Burkhart CN, Burkhart KM. An assessment of topical and oral prescription and over-the-counter treatments for head lice. J Am Acad Dermatol 1998;38: McCarthy JS, Kemp DJ, Walton SF, et al. Scabies: more than just an irritation. Postgrad Med J Online 2004;80: Burgess IF. Human Lice and their management. Adv Parasitol 1995;36: Meinking TL, Taplin D. Infestations: pediculosis. In Elsner P, Eichmann A, eds. Sexually transmitted diseases: Prescriber 19 January

8 Key points worldwide resistance to several topical insecticides is growing, with head lice resistance to permethrin and malathion becoming an increasing problem throughout the UK there is still an overall good response to carbaryl as a head lice treatment in the UK, but resistance is beginning to emerge in some areas the main method of treatment for scabies is by topical application of a scabicide overnight to the whole body from head to toe in the management of scabies it is important to treat all family members and close contacts simultaneously to avoid reinfestation crusted ( Norwegian ) scabies is a hyperinfestation, more difficult to eradicate than common scabies and may require treatment with ivermectin on a namedpatient basis advances in diagnosis and treatment. Basel, Switzerland, Burgess IF, Brown CM, Lee PN. Treatment of head louse infestation with 4 per cent dimeticone lotion: randomised controlled equivalence trial. BMJ 2005;330: Downs AM, Harvey I, Kennedy CTC. The epidemiology of head lice and scabies in the UK. Epidemiol Infect Resources Further reading Primary health care guide to common UK parasitic diseases. Figueroa J, Hall S, Ibarra J, eds Available from Community Hygiene Concern (see below). Textbook of dermatology. Champion RH, Burton JL, Burns DA, et al, eds. Oxford: Blackwell Science, Patient information British Association of Dermatologists. Patient information and leaflets available online: public/leaflets. Department of Health head lice factsheet is available online: Printed copies are available from the Department of Health, tel: ; fax: ; dh@prolog.uk.com. Developing Patient Partnerships, Tavistock House, Tavistock Square, London WC1 9JP. Tel: ; fax: ; dpp@bma.org.uk; 1999;122: Downs AMR, Stafford KA, Hunt L, et al. Widespread insecticide resistance in head lice to the over-the-counter pediculocides in England and emerging carbaryl resistance. Br J Dermatol 2002;146: Roberts RJ, Casey D, Morgan DA, et al. Comparison of wet combing with malathion for treatment of head lice in the UK: a pragmatic randomised controlled trial. Lancet 2000;356: Hill N, Moor G, Cameron, et al. Single blind randomised, comparative study of the Bug Buster kit and over the counter pediculicide treatments against head lice in the United Kingdom. BMJ 2005;331: Hedrin 4 per cent lotion (dimeticone). Summary of product characteristics. Thornton & Ross Ltd, November Does dimeticone clear head lice? Drug Ther Bull 2007; 45: Chosidow O. Scabies and pediculosis. Lancet 2000; 355: Strong M, Johnstone PW. Interventions for treating scabies (Review). Cochrane Database Syst Rev 2007, Issue 3. In: The Cochrane Library, Issue 3, Heukelbach J, Feldheimer H. Ectoparasites the underestimated realm. Lancet 2004;363: Dr Connolly is a consultant dermatologist at The Adelaide & Meath Hospital, Dublin, incorporating The National Children s Hospital, Tallaght website: Leaflets available on detecting and treating head lice for patients. Groups and organisations Community Hygiene Concern, Manor Gardens Centre, 6-9 Manor Gardens, London N7 6LA. Helpline: ; fax: ; bugbusters2k@yahoo.co.uk; website: Produces Bug Buster kits ( p&p), DVD/ video ( p&p) and primary-care guide ( p&p) containing information on head lice, crab lice and scabies (see Further reading). The website also provides further advice and information for patients. Websites provides advice and patient information sheets on scabies and head lice. website links for both head lice and scabies. 28 Prescriber 19 January

9 Prescription review The number of prescriptions for parasiticidal preparations has been falling by about per year and in 2006 totalled approximately at a cost of 2.6 million about half the volume and cost recorded in For comparison, the OTC market for products to treat infestations was worth 18.6 million in Ninety per cent of scrips were for malathion or permethrin products, but preparations that are not recommended by the BNF are still widely prescribed. These include foam aerosols of phenothrin (Full Marks) and malathion shampoo (Quellada), and benzoyl benzoate, which is not recommended for scabies due to its adverse effects and lesser efficacy. One of the most popular brands in 2006 was Lyclear Creme Rinse (permethrin), even though it offers insufficient contact time against head lice. Together, these products accounted for 21 per cent of scrips and 12 per cent of spending (totalling over ) in this category. No. scrips Cost ( 000s) (000s) Benzyl benzoate Ascabiol Emulsion benzyl benzoate application Carbaryl Carylderm 1% Liquid Carylderm 0.5% Lotion No. scrips Cost ( 000s) (000s) Quellada-M 1% Cream Shampoo Suleo-M 0.5% Lotion Permethrin Lyclear 1% Creme Rinse Lyclear 5% Dermal Cream permethrin cream Malathion Derbac-M 0.5% Liquid Prioderm 0.5% Lotion Quellada-M 0.5% Liquid Phenothrin Full Marks 0.5% Foam Aerosol Full Marks 0.5% Liquid Full Marks 0.2% Lotion Table 2. Number of prescriptions and cost of drugs used to treat head lice and scabies, England, 2006 Datafile: Pediculicides and scabicides Table 1. Preparations for head lice Drug Available as Strength/form Application Cost 1 benzyl Ascabiol 25% emulsion apply to affected area, wash off after /100ml benzoate benzyl benzoate 25% emulsion hours. Repeat 2-3 times if necessary 2.50/500ml carbaryl Carylderm 0.5% alcohol-based apply to dry hair; leave for hours, then 2.28/50ml lotion shampoo 1% aqueous liquid apply to dry hair and leave for 12 hours, then 2.28/50ml shampoo malathion Derbac M 0.5% aqueous liquid apply to dry hair and wash off after 12 hours 2.22/50ml, 5.70/200ml Prioderm 0.5% alcohol-based apply to dry hair and wash off after /50ml, lotion hours 5.70/200ml 1 Basic NHS cost. Prices MIMS/Drug Tariff, November Prescriber 19 January

10 Datafile Table 1. Preparations for head lice (cont.) Drug Available as Strength/form Application Cost 1 malathion Quellada M 0.5% liquid emulsion apply and wash off after 12 hours or next 1.85/50ml, (cont.) day 4.62/200ml 1% shampoo shampoo in, leave for 5 minutes, rinse and 2.18/40g repeat procedure. Repeat 3 times at 3-day intervals permethrin Lyclear Creme 1% lotion apply after shampooing, leave for 10 minutes 2.38/59ml, Rinse then rinse off twin pack 4.32 phenothrin Full Marks 0.2% alcohol-based apply to dry hair, wash off after 2 hours and 2.22/50ml, lotion comb when wet 5.70/200ml 0.5% liquid emulsion apply to dry hair, wash off after 12 hours and 2.22/50ml, comb when wet 5.70/200ml 0.5% mousse apply to dry hair, wash off after 30 minutes 2.44/50g, and comb when wet 5.42/150g dimeticone Hedrin 4% lotion apply to dry hair, wash off after 8 hours. 2.98/50ml, Repeat after 7 days 6.83/150ml 1 Basic NHS cost. Prices MIMS/Drug Tariff, November 2007 Table 2. Scabicides Drug Available as Strength/form Application Cost 1 benzyl Ascabiol 25% emulsion after a hot bath apply to whole body except head 1.40/100ml benzoate benzyl benzoate 25% emulsion and face, repeat within 5 days if necessary 2.50/500ml crotamiton Eurax 10% lotion and after a warm bath, dry skin thoroughly and rub lotion cream well onto entire body surface except face and scalp; 2.99/100ml repeat once every 3-5 days cream 2.26/30g, 3.95/100g malathion Derbac M 0.5% aqueous apply to whole body except head and face, wash 2.22/50ml, liquid off after 24 hours 5.70/200ml Quellada-M 0.5% liquid 1.85/50ml, liquid emulsion 4.62/200ml permethrin Lyclear Dermal 5% cream apply to whole body except head and face, wash 5.71/30g Cream off 8-12 hours later. Repeat once after 7 days if permethrin 5% cream necessary 5.52/30g 1 Basic NHS cost. Prices MIMS/Drug Tariff, November Prescriber 19 January