Evidence based Dermatology - part 8 pptx

34. Bonifaz A, Martinez-Soto E, Carrasco-Gerrard E, Peniche J. Treatment of chromoblastomycosis with itraconazole, cryosurgery and a combination of both. Int J Dermatol 1997: 36 :542–7. 35. Patel P, Ramanathan J, Kayser M, Baran J Jr. Primary cutaneous cryptococcosis of the nose in an immunocompetent woman. J Am Acad Dermatol 2000: 43 :344–5. 36. Noble RC, Fajardo LF. Primary cutaneous cryptococcosis: review and morphologic study. Am J Clin Pathol 1972: 57 :13–22. 37. Antony SA, Antony SJ. Primary cutaneous cryptococcus in nonimmunocompromised patients. Cutis 1995: 56 :96–8. 38. Hamann ID, Gillespie RJ, Ferguson JK. Primary cryptococcal cellulitis caused by Cryptococcus neoformans var. gattii in an immunocompetent host. Aust J Dermatol 1997; 38 :29–32. 39. Sanchez P, Bosch RJ, de Galvez MV et al. Cutaneous cryptococcosis in two patients with acquired immuno- deficiency syndrome. Int J STD AIDS 2000; 11 :477–80. 40. Coker LR, Swain R, Morris R, McCall CO. Disseminated cryptococcosis presenting as pseudofolliculitis in an AIDS patient. Cutis 2000; 66 :207–10. 41. Naka W, Masuda M, Konohana A et al. Primary cutaneous cryptococcosis and Cryptococcus neoformans serotype D. Clin Exp Dermatol 1995; 20 :221–5. 42. Glassman SJ, Hale MJ. Cutaneous cryptococcosis and Kaposi’s sarcoma occurring in the same lesions in a patient with the acquired immunodeficiency syndrome. Clin Exp Dermatol 1995; 20 :480–6. 512 Evidence-based Dermatology Part 3: The evidence Section D: Infestations Editor: Berthold Rzany Background Definition Scabies is an itchy immune hypersensitivity reaction to infestation of the skin by the mite Sarcoptes scabiei . Adult female mites burrow through the skin at the junction of the stratum corneum and the prickle cell layer, where they lay their eggs. Burrows then move out progressively towards the skin surface with the stratum corneum. Adult males and juvenile mites (larvae and nymphs) live mostly at the skin surface but may make temporary burrows for moulting from one development stage to another. Infestation of immune-competent people is most common on the hands, digits and finger webs, and on the wrists. The flexor surfaces of the elbows, the axillae, ankles, buttocks, breasts and male genitalia may also be infested. In the elderly, infants and the immunocompromised the infestation may be more diffuse, including the head and neck, and palms and soles. Incidence/prevalence We found no recent published data on incidence or prevalence from any developed country. Scabies is a common public health problem in developing countries, where prevalence may exceed 50% in some communities, and prevalence has been estimated at 300 million cases worldwide. 1 Older studies have shown that prevalence is highest in teenagers and schoolchildren. 2–4 However, incidence has increased recently in the institutionalised elderly. Historical data from Denmark show that epidemic cycles arise at 15–20-year intervals. 2 Aetiology/risk factors Transmission of scabies mites occurs during relatively prolonged skin–skin contact. The infection is most frequent in communities with long-term conditions of overcrowding, and increases following social disruption. Reduction of immune competence increases the risk of contracting infestation, with a concomitant risk of high mite numbers. We found no evidence that hygiene influences risk, although good hygiene may ameliorate symptomatic presentation. 5 Prognosis Scabies is not life threatening, but the severe, persistent itch and secondary infections may be debilitating and disfiguring. Long-term infestations are inherently immunodepressive and in susceptible people may lead to development of a form of the disease in which large numbers of mites inhabit hyperkeratotic plaques. These shed skin plaques may be a source of reinfection and transmission. 6 In some circumstances scabies infected with haemolytic streptococci may result in acute glomerulonephritis. 5 Diagnosis A diagnosis of active infestation is confirmed only by finding mites, mite ova or faecal pellets (scybala). Mite burrows in the skin, the distribution of papular lesions and bilateral itch not affecting the head, chest or back are indicative but are not confirmation of an active infestation. Nodular lesions around the axillae, navel or on the penis or scrotum are pathognomonic, but may persist for months after cure. 37 Scabies Ian F Burgess 515 Aims of treatment The aim of treatment is to eliminate infestation by killing or removing all mites and their eggs. Outcomes There are no established standard criteria for making a diagnosis or judging treatment success. Trials used different methods, and in many cases the method was not stated. Treatment success should be given as the percentage of people completely cleared of scabies mites, ova or faecal pellets in skin scrapings viewed under magnification. Clinical success includes elimination of papular and vesicular eruptions and pruritus. Ideally, outcomes should be assessed 28 days after the start of treatment. This allows lesions to heal. If treatment fails, eggs hatch within 3 days and emerging mites become mature 9–10 days later. Methods of search 1. The initial search conducted for a systematic review compiled in 1999 7 used the following primary sources: Cochrane Central Register of Controlled Trials; Medline 1966 to 1997; Embase 1974 to 1997; records of military trials from the UK, US and Russia, and the specialist register of the Cochrane Diseases Group. 2. Clinical evidence search, May 2000 3. Medline update search for evidence-based dermatology, January 2002 4. Hand searching of relevant journals QUESTIONS How successful are topical treatments for scabies? For example, would a topical treatment be suitable for treating newly diagnosed scabies in a 16-year-old girl? (Figure 37.1) Insecticide-based pharmaceutical products Benefits We found one systematic review (search date 1997) that examined four trials. In each case a single application of treatment was given unless stated otherwise. One study (150 adults and children) compared 5% permethrin cream with 10% crotamiton cream (a non-insecticide) and 1% lindane lotion. 8 It used clinical features as the measure of success. The results showed that permethrin was slightly, but not significantly, more likely to cure (49/50 (98%) people with 516 Evidence-based Dermatology a) b) Figure 37.1 a) Papules, pustules and impetaginisation in the vicinity of scabies burrows and b) excoriated rash and papules on the wrists in simple scabies permethrin versus 44/50 (88%) with crotamiton; relative risk (RR) 1·11, 95% confidence intervals (CI) 1·0–1·2). The same study also found permethrin to be significantly more effective than lindane: permethrin cured 49/50 (98%) whereas lindane cured only 12/50 (24%) people (RR 4·08, CI 2·5–6·7). 8 A single randomised controlled trial (RCT) comparing 5% permethrin cream with 10% crotamiton cream evaluated cure by elimination of parasites. 9 It found permethrin to be more effective after 14 and 28 days. After 14 days 33/47 (70%) of people in the permethrin group and 41/47 (87%) in the crotamiton group still had lesions. At this point 10 people in the crotamiton group were withdrawn from the study because their infestation was exacerbated. However, after 28 days 42/47 (89%) people in the permethrin group were free from parasites compared with 28/47 (60%) in the crotamiton group (RR 1·5, CI 1·2–1·9). 9 This study also recorded patients’ subjective reports on the persistence of pruritus, which was found to be closely related to effectiveness of the treatments. Two trials compared the effect of 5% permethrin cream with that of 1% lindane lotion. A small study (46 people) found fewer people improved 14 days after using permethrin (13/23 (57%) versus lindane 20/23 (87%); P <0·02), but a significantly better rate of cure, by parasitological examination, for permethrin at 28 days (21/23 versus 15/23; P <0·025, RR 1·4, CI 1·0–1·9). 10 A larger trial (467 people) did not identify parasites but recorded a significant decrease in the number of lesions persisting in both groups after 14 ± 3 days. At 28 ± 7 days success rates were 181/199 (91%) after using 5% permethrin cream, compared with 176/205 (86%) after using 1% lindane lotion ( P = 0·18, RR 1·06, CI 0·9–1·1). 11 At final assessment, significantly fewer of the permethrin group (27/194 (14%)) had persistent itch compared with 49/197 (25%) of the lindane group ( P = 0·007). 11 The systematic review identified no RCTs comparing 0·5% malathion, in either aqueous or alcohol vehicles, with other treatments. Case series and one quasi-randomised trial suggest that it is effective, with a cure rate of over 80% at 4 weeks. 12–14 Drawbacks Only minor adverse effects have been reported for most insecticides. The exception is lindane, for which there are extensive reports of effects related to overdosing and absorption. 15,16 Despite recognised neurotoxicity, lindane is still widely used, partly because alternatives are not readily available in many countries. Lindane passes transdermally during treatment and other exposures, and may be stored in fatty tissues and excreted in breast milk. 17 Acute exposure to lindane during scabies treatment has potentiated seizures in people on medication that reduces seizure threshold. 18,19 Therefore, lindane appears to be contraindicated for those undergoing therapy for HIV infection, 18 or attention deficit hyperactivity disorder using amphetamine, 19 and in those who suffer from epileptiform seizures. Concern has been expressed that lindane may be a risk factor for triggering of seizures in epileptics because it may alter liver cell function. Lindane does cause oxidative stress but does not appear to modify liver microsomal function, and in experimental systems these effects were mitigated by prior treatment with phenobarbital. 20,21 Consequently, those being treated with barbiturates may be at lower risk of suffering side-effects from lindane. However, it is not clear whether people receiving anticonvulsant drugs in general are at greater risk of having seizures if exposed to lindane. Various studies have shown that the solvent vehicle plays an important role in the rate of transdermal absorption of lindane. 22,23 Additionally, much of the drug can also be absorbed as the treatment is washed off because 517 Scabies a depot of lindane builds up in the stratum corneum. 23–25 In many countries, scabicides are still applied after a hot bath but the resultant peripheral vasodilation is likely to enhance transdermal absorption. A related increase in passage of lindane through the dermis has been identified if soap and hot water are used to remove the acaricide at the end of the treatment process. Absorption can be minimised if cool water alone is used to remove residues of lindane products before bathing. 25 An investigation of the absorption of permethrin and lindane through human cadaver skin in vitro found that lindane achieved a rate of 2 microgram/hour/cm 2 in less than 5 hours, whereas the rate for permethrin was one-tenth of this after 10 hours. However, fresh guinea pig skin absorbed both at the same rate. 26 Most RCTs have reported no serious adverse events using these topical insecticide-based products. One RCT reported five serious adverse events, two possibly associated with permethrin (rash and diarrhoea) and three possibly associated with lindane use (pruritic rash, papules and diarrhoea). 11 Post-marketing surveillance of permethrin use in the USA from 1990 to 1995 found six adverse events per 100 000 units of product (equivalent to one central nervous system adverse event for each 500 000 units of permethrin used). 27 Case series based on community intervention studies have reported a burning paraesthesia as one of the most frequent adverse events following permethrin use, particularly in the immunodeficient. 27,28 A burning sensation was the most frequent adverse event, although not significantly so, in the largest RCT, with 23 events in 233 people following application of 5% permethrin, compared with 12/232 after 1% lindane lotion ( P = 0·08). 11 Comment Generally, it is believed that all mites and their eggs are killed soon after treatment. Confirmation of cure is therefore difficult because mites may not be detectable in post-treatment skin scrapings. It is therefore impossible to determine success until sufficient time has passed to permit the various lesions resulting from the infestation to heal. Many people show considerable improvement after 14 days but a definitive clinical cure cannot be concluded until about 28 days after treatment, when all lesions present at the time of treatment should either be healed or resolving, without new lesions developing. Three of the RCTs were conducted in developing countries. The fourth study was divided between the USA and Mexico. 11 It is not known whether scabies mites may be more susceptible to treatment in communities where treatments are not generally available but it is likely that prior exposure to acaricidal chemicals may select for reduced sensitivity in mites in developed countries, and some cases of suspected resistance, particularly to lindane, have been recorded. 27,29 Lindane products are still used against scabies in most western countries, despite its relative toxicity. In the UK the only lindane product was withdrawn on commercial grounds. The former market-leading product in the USA is now no longer produced for the same reason. Implications for clinical practice The evidence indicates that permethrin is more effective than crotamiton, lindane and malathion, and has been associated with fewer side-effects than lindane. However, the high cost of permethrin may limit its use in some communities. Permethrin is probably more likely to be effective with one application than are other insecticides but a second treatment may be necessary for all. 30 Non-insecticide-based acaricides Benefits Randomised studies comparing the non- insecticide antiscabies agent crotamiton with 518 Evidence-based Dermatology insecticide-based treatments were described above. We found one trial (158 adults and children) comparing 25% benzyl benzoate with sulphur ointment (concentration of sulphur not given) in a community study in India. 31 In this study patients were first scrubbed in a bath; the treatments were then applied three times in 24 hours (morning, night, next morning). Assessments were made at approximately 5-day intervals. No significant difference was found between the treatments regarding improvement of lesions at 9–10 days (benzyl benzoate 68/89 (76%) versus 45/69 (65%) with sulphur; RR 1·17, CI 1·0–1·4). At this time, if lesions remained the patients were treated again so that by 14–15 days improvement of symptoms in the benzyl benzoate group was 81/89 (91%) compared with 67/69 (97%) for sulphur (RR 0·94, CI 0·9–1·0), which was also not significantly different. Non-controlled studies and case studies have indicated a variable effectiveness for both benzyl benzoate (20% emulsion, 32 25% emulsion, 14 25% cream 33 ) and sulphur ointment (5%, 35 6%, 34 or 10% 32,35 ). Activity of these acaricides is related to the concentration of active drug in the vehicle and the number of times they are applied. In general, benzyl benzoate appears to require a minimum of two applications and sulphur may require several applications over one week or longer. 36 We found a single RCT evaluated by the systematic review comparing pork fat containing 1% salicylic acid and cold cream as ointment vehicles for delivery of sulphur. 37 The numbers in this study were small (51 confirmed cases) and differences of efficacy could have been due to chance effects. Every participant applied the sulphur ointment on three consecutive nights and then again three days later. Evaluations were made on the tenth day after the last treatment. This study is more relevant for the side-effects observed, described below. We found that other non-insecticide active materials have only been described in non- randomised studies and case series. One non- randomised study comparing 5% sulphur ointment, 1% lindane cream, 25% benzyl benzoate cream, 10% crotamiton lotion, and 0·2% nitrofurazone in a water-soluble ointment, found nitrofurazone was least effective, with a 70% cure rate. 33 A case series of 20 patients using the same nitrofurazone ointment produced “complete clinical cure” in 80% of cases. 38 Monosulfiram is now little used either as a liquid (25% before dilution for use) or a soap. Most studies are of poor quality and more than 50 years old, and more recent case studies show a high incidence of side-effects (see below). Thiabendazole has been used as a 5% and a 10% cream applied over several days. In one case series, 5/19 (26%) were still infested after 5% cream was used twice daily for 5 days. The remaining patients were cured after a further 5 days of treatment. 39 Another case series, in which 10% cream was used, achieved 80% success after 5 days. 40 Drawbacks Generally, only minor adverse reactions have been reported for non-insecticide treatments for scabies. Most of these have been related to skin irritation, often following repeated or multiple applications of the formulation. The RCT comparing vehicles for sulphur ointment 37 did not provide adequate data for a full analysis of effects. Side-effects were reported in patients and close contacts within 6 days of first being treated with either cold cream or pork fat with 1% salicylic acid: pruritus (31% versus 60%), xerosis (24% versus 34%), burning sensation (12% versus 17%), erythema (10% versus 2%), and keratosis (2% versus 15%). 37 Where sulphur is used in developed countries it is normally applied in petroleum jelly and similar skin reactions have been reported as side-effects 519 Scabies from case studies and series. 36,41 Similar irritant reactions occur with repeat treatments using benzyl benzoate, particularly if naturally derived rather than synthetic material is used. 36,42 In one RCT approximately 25% of people reported an increase in pruritus and dermatitis after treatment with two applications of 10% benzyl benzoate. 43 Monosulfiram has been associated with a systemic adverse event in a number of case reports in which the people developed dermal oedema, flushing, sweating and tachycardia, especially after ingesting alcohol within 24 hours of treatment. 44–46 This reaction occurs because monosulfiram is chemically related to disulfiram, used in the treatment of alcoholism (Antabuse). Multiple applications of crotamiton can result in dermatitis and there is one report of a suspected link with methaemaglobinaemia. 16,36,47 Comments Most studies in this group are not comparable because of differences in the formulations used, the concentrations of the active substances and the duration or number of applications. Evidence for activity is limited in each case, and it is possible that some of the effectiveness is partially related to a physical effect, for example sulphur in a heavy greasy base may physically trap and subsequently remove developmental stages of the mite from the skin surface. The mode of action of crotamiton is not understood and there is some doubt about both its acaricidal and antipruritic activities. Similar questions may apply to all of the non-insecticide-based treatments. The fact that these treatments are cheap means that they are more likely to be used in developing countries where source materials may be less well characterised. Most of these compounds have been in use for around 50 years and there is some suspicion that resistance is developing in some areas. 16 Implications for clinical practice All of these products are likely to require 2–4 applications and are not particularly cosmetic. They may therefore suffer from compliance problems. However, the low cost and relative safety, apart from skin irritancy, make non- insecticide-based acaricides attractive alternatives to insecticide-based products where mites may have developed resistance or if cost is an issue. How successful are oral treatments for scabies? Would an oral treatment be suitable for treating an 82-year-old resident in a nursing home? (Figure 37.2) Orally administered treatments Benefits We found one systematic review examining two small RCTs, one of which had inadequate follow up. A placebo-controlled RCT (55 adults and children) found that significantly more people treated with ivermectin, 200 microgram/kg, (23/29 (79%)) were free from symptoms at 7 days compared with those treated with placebo (2/26 (8%) RR 10·3, CI 2·7–39·6). The code was then broken and the controls and all patients who had not improved received ivermectin. 48 A comparative RCT (44 people) found no significant difference in improvement of 520 Evidence-based Dermatology Figure 37.2 Hyperkeratotic crusts may develop in abnormal sites. With permission from Institute of Dermatology lesions between ivermectin, 100 microgram/kg, (16/23 (70%)) and benzyl benzoate 10%, applied twice over 2 days (10/21 (48%)) at 30 days (RR 1·46, CI 0·9–2·5). 43 We also found one RCT (85 people) comparing ivermectin, 200 microgram/kg, with 5% permethrin cream, evaluated at 1, 2, 4 and 8 weeks. 49 In this study a single dose of ivermectin relieved symptoms in significantly fewer people (28/40 (70%)) than permethrin (44/45 (98%) RR 0·72, CI 0·6–0·9), but when a second dose of treatment was given after 2 weeks there was no significant difference in the improvement rate between the ivermectin group (38/40 (95%)) and the permethrin group, in which everyone was cured . A second RCT (53 people, 43 completing the study) found ivermectin, 150–200 microgram/kg, to be statistically equivalent to 1% lindane lotion. 50 After 15 days 14/19 (74%) had improved with ivermectin, compared with 13/24 (46%) treated with lindane (RR 1·36, CI 0·9–2·1). At 29 days all but one person in each group were cured (18/19 (95%) with ivermectin versus 23/24 (96%) with lindane; RR 0·99, CI 0·9–1·1). Drawbacks All the RCTs were too small to provide adequate safety data for use of ivermectin against scabies, particularly in children. Ivermectin has been used extensively in community control programmes for onchocerciasis and filariasis and there have been few reports of serious adverse events. 51,52 There has been one report of a significant increase in mortality rate in a psychogeriatric unit (15/42 (36%); P = 0·001) within 6 months of ivermectin use compared with controls in the same care facility over a 3-year period. 53 However, each resident in the unit had previously received several applications of other scabies treatments, including lindane and permethrin. Use of ivermectin in the elderly in other countries has not resulted in any similar increase in mortality. 54 Comment Ivermectin has been licensed for use against scabies only in France. However, its use on a named-patient basis has become widespread as a component of treatment for hyperkeratotic scabies in which it is often difficult to kill all the mites because of the limited penetration of the plaques by topical acaricides. In this condition, ivermectin can reach trophic mites by incorporation in the living cell layer on which the mites feed. However, ivermectin is unlikely to have any effect on mite eggs, and failures of treatment have been reported unless either dosing is repeated or a topical scabicide is used concurrently. 55–57 So far no proper dosing studies using ivermectin have been performed, and the relative underdosing using both ivermectin and benzyl benzoate in one study indicates how important a contribution to knowledge this would be. 43 Implications for practice A reliable and safe oral treatment is the most attractive option for dosing and compliance with scabies treatment. Ivermectin has not yet been evaluated sufficiently to determine the most appropriate dosing regimen, but it can be a useful adjunct to conventional treatment approaches. Additional comment The evidence for effectiveness of scabies treatments is still largely rudimentary and the majority of studies have employed inadequate criteria for diagnosis and evaluation of efficacy. What evidence exists indicates that none of the topical products is reliable with a single application. The limited evidence available for ivermectin is far from the aspirations expressed by those dealing with problems of long-term infestation. Consequently, further investigation is required for this and other treatments to determine adequate drug regimens. 521 Scabies [...]... with “bug-busting”.21 After 14 days more people treated with permethrin still had lice 527 Evidence- based Dermatology (8/ 11 (73%) versus 8/ 14 (57%); RR 1·27, CI 0·7–2·3; NNT 6, CI 0·4–1·4) An unpublished community -based pragmatic RCT (275 people), (SSL International, personal communication, 19 98) compared single applications of phenothrin 0·2% lotion with both phenothrin 0·5% mousse and “bug-busting”... immunologic follow-up of patients who stop 1997;77:315–16 33 Zhai H, Packman EW, Maibach HI Effectiveness of ammonium solution in relieving type I mosquito bite symptoms: a double-blind, placebo-controlled study Acta Derm Venereol 19 98; 78: 297 8 venom immunotherapy J Allergy Clin Immunol 1991 ;88 :339– 48 49 Mosbech H, Malling H-J, Biering I et al Immunotherapy with yellow jacket venom Allergy 1 986 ;41:95–103... children J Pediatr 1 980 ;97:177 84 HJ, Schulz KH Die Bienen-und Wespengiftallergie Therapiewoche 1 981 ;31:6371 98 Grimm I Die kausale Behandlung der Insektengiftallergie Z Hautkr 1 982 ;57: 78 85 Diez Gómez ML, Gancedo SQ, de Pàramo BJ Venom 99 Jarisch R Die Bienengiftallergie (Modell einer IgE- immunotherapy: tolerance to a 3–day protocol of rush- mediierten Soforttypallergie) Wien klin Wschr 1 980 ;92 immunotherapy... reactions • We found good evidence evaluating the effect of VIT However, because of the potentially life-threatening nature of Hymenoptera venom hypersensitivity, it seems unethical to perform double-blind, placebo-controlled trials Therefore our evaluation had to be based mainly on lower-level evidence – non-randomised, non-controlled interventional studies • We found good evidence that pretreatment... et al Anaphylactic shock after insect-sting challenge in 1 38 persons with a previous insect-sting reaction Ann Intern Med 1993;1 18: 161 8 Exp Allergy 1991;21: 281 8 42 Müller U, Mosbech H, Aberer W et al Adrenaline for emergency kits Allergy 1995;50: 783 –7 43 Tryba M, Ahnefeld FW, Barth J et al Acute therapy of anaphylactoid reactions: Results of an interdisciplinary 28 Van der Zwan JC, Flinterman J, Jankowski... assays immunotherapy J Allergy Clin Immunol 1990 ;86 :775 80 Int Arch Allergy Appl Immunol 1979;60:1 48 541 Evidence- based Dermatology 104 Näßlein H, Köstler C, Gläck H, Baenkler HW, Kalden JR Diagnostik und Therapie der Bienen-und 110 Reimers A, Hari Y, Müller U Reduction of sideeffect from ultrarush immunotherapy with honeybee Wespengiftallergie Therapiewoche 1 984 ;34:421 venom by pretreatment with fexofenadine:... positive skin-prick test received VIT for 6–10 weeks.14 A significantly reduced incidence of systemic reactions after controlled sting challenges was observed in the VIT group compared with the placebo group (5% versus 58% ) and with a group that received whole-body extract (64%) In the second trial, 74 children with a history of systemic reactions and a 535 Evidence- based Dermatology positive skin-prick... reactions in wasp-sensitive patients treated with wasp venom ranged from 0% to 34% After pooling we calculated a rate of 14% (329/2 383 patients).14, 28, 50,51,56,60,64–69 ,83 –1 08 Insect bites Comments Because Hymenoptera venom hypersensitivity is potentially life threatening, it seems unethical to perform double-blind, placebo-controlled trials This may explain why we found only two RCTs and few non-randomised... 19 98, updated February 2001 (Search date: February 2001; primary sources: Cochrane Central Register 525 Evidence- based Dermatology of Controlled Trials, Medline, Embase, BIDS SC, Biosis (biological abstracts database), and Toxline) • Dermatological Evidence update search July 2001 • Hand searching of relevant journals QUESTIONS How successful are treatments for head lice? Case scenario 1 A 10-year-old... treatment of scabies Pediatr Dermatol 1991 ;8: 64–6 38 Chowdhury SPR Nitrofurazone in scabies Lancet 1977;i:152 Bull World Health Organ 1 989 ;67:707–19 53 Barkwell R, Shields S Deaths associated with ivermectin treatment of scabies Lancet 1997;349:1144–5 54 Diazgranados JA, Costa JL Deaths associated with ivermectin treatment of scabies Lancet 1997;349:16 98 523 Evidence- based Dermatology 55 Corbet EL, Crossley . necessary for all. 30 Non-insecticide -based acaricides Benefits Randomised studies comparing the non- insecticide antiscabies agent crotamiton with 5 18 Evidence- based Dermatology insecticide -based treatments. with the acquired immunodeficiency syndrome. Clin Exp Dermatol 1995; 20 : 480 –6. 512 Evidence- based Dermatology Part 3: The evidence Section D: Infestations Editor: Berthold Rzany Background Definition Scabies. J Med 1995; 332 :612. 524 Evidence- based Dermatology 38 Head lice Ian F Burgess and Ciara S Dodd 525 Background Definition Head lice ( Pediculus capitis ) are blood-feeding insects that are obligate