Assessment of topical versus oral ivermectin as a treatment for head lice

Many medications are available for treatment of pediculosis capitis including ivermectin. Our aim is to compare the efficacy and safety of topical versus oral ivermectin in treatment of pediculosis capitis. Sixty‐two patients with proved head lice infestation were included and divided into group I (31 patients; received single topical application of 1% ivermectin) and group II (31 patients; received single dose of oral ivermectin). Treatment was repeated after 1 week for nonresponders. At 1 week after treatment, the eradication rates and improvement of pruritus were significantly higher among patients who received topical than oral ivermectin. When a second treatment, topical or oral, was given to nonresponders, the cure rates of infestation and pruritus was 100% and 97% among patients treated with topical and oral ivermectin, respectively with no significant difference between the two groups. This study suggests that both topical and oral ivermectin demonstrate high efficacy and tolerability in treatment of pediculosis capitis. However, a single treatment with topical ivermectin provides significantly higher cure of infestation and faster relief of pruritus than oral ivermectin. In addition, whether topical or oral ivermectin is used to treat head lice, a second dose is required in some cases to ensure complete eradication.     

Oral ivermectin for head lice: a comparison with 0.5 % topical malathion lotion

Background: Reports of treatment failure of head lice have become increasingly common. Oral ivermectin has been proposed as a potential alternative for the treatment of head lice infestation. The aim of this study was to compare the efficacy of oral ivermectin with topical malathion lotion in the treatment of head lice. Patients and methods: Eighty apparently healthy children with head lice infestation were randomly assigned to 2 groups, with 40 patients in each. The first group received oral ivermectin as a single dose of 200 μg/kg and the second group received single topical application of malathion lotion 0.5 %. Follow up visits were done at days 8, 15 and 29. A second dose of either drug was given at day 8 in case of treatment failure. Results: After a single dose, complete cure was achieved in 77.5 % and 87.5 % of ivermectin and malathion groups respectively. After the second dose for nonresponders, the cure rate increased to 92.5 % in the ivermectin group and 95 % in the malathion group. No major adverse effects were observed in either group. Conclusions: Oral ivermectin is a promising effective approach for the treatment of head lice and could be an ideal substitute for conventional pediculicides.     

Evidence for double resistance to permethrin and malathion in head lice

A rising prevalence of head lice among school children and rising sales of insecticides with anecdotal evidence of their treatment failure, led us to examine whether head lice in Bristol and Bath were resistant to the insecticides available for treating head lice. Ten schools in Bristol and Bath were visited to collect field samples of head lice. A comparison was made of the survival rates of fully sensitive laboratory reared body lice and field samples of head lice on insecticide exposure. To confirm the in vitro relevance of these tests we performed supervised treatments of affected subjects with malathion or permethrin. There were significant differences (P < 10-6 Fishers exact test) between head and body lice survival for malathion and permethrin exposure, but not for carbaryl. There was an 87% failure rate for permethrin and a 64% failure rate for malathion with the topical treatment of a selected number of infested school children. We conclude that there is a high resistance to permethrin and malathion, but head lice remain fully sensitive to carbaryl. This is the first report of doubly resistant head lice. As permethrin, phenothrin (a very similar synthetic pyrethroid) or malathion are the active ingredients in all the over-the-counter head lice treatments in the U.K., then it is likely that head lice prevalence will continue to increase. The resistance against permethrin employed by the head louse is probably the kdr (knockdown resistance) mechanism, and an enzyme-mediated malathion-specific esterase is the likely mechanism against malathion.     

Efficacy and safety of a combination regimen of phenothrin and ivermectin lotion in patients with head lice in Okinawa,Japan

In Japan, pyrethroid-resistant head lice have been increasing; however, only 0.4% phenothrin, a pyrethroid drug, is available as an over the counter formulation. In recent years, Sumithrin^® Lotion containing 5% phenothrin (PHT) was approved for scabies. In the USA, Sklice^® Lotion containing 0.5% ivermectin (IVM) is used for the treatment of pyrethroid-resistant head lice. Therefore, to enhance the treatment of head lice in Japan, we conducted a clinical study to confirm the efficacy and safety of a combination regimen of PHT and IVM (PI regimen). Twelve cases were enrolled and PHT was applied to all patients on day 1. On day 8, five patients (41.7%) were lice free, and PHT was applied again. Notably, seven patients were not lice free and were switched to IVM. The rate of patients who were lice free on the PI regimen, which was the primary end-point, was 75.0% on day 15 and 91.7% on day 22. No adverse events were reported. A genetic analysis of the head lice collected at each visit revealed a kdr mutation in all patients. These results suggest that the PI regimen is safe and effective for the treatment of pyrethroid-resistant head lice in Japan.     

Widespread insecticide resistance in head lice to the over-the-counter pediculocides in England, and the emergence of carbaryl resistance

BACKGROUND: Increasing resistance to insecticides used for the control of head lice infestation has been documented over the last decade. Treatment failure and tolerance to insecticides have been validated in a number of studies undertaken in several U.K. centres. OBJECTIVES: To establish the extent of insecticide resistance in head lice and acetylcholinesterase activity in the presence of carbaryl in head lice. METHODS: Head lice were collected from school children in four centres across England (Exmouth, Loughborough, Leeds and South Shields), and tested in their response to the insecticides permethrin, phenothrin, malathion and carbaryl. Data were compared with information collected in Bristol and Bath in 1998 and with susceptible body lice. The activity of louse acetylcholinesterase was measured with and without carbaryl in head lice collected in Bristol, Leeds, Loughborough and in body lice. The efficacy of a 1% carbaryl lotion was compared in children in Bristol and Leeds. RESULTS: Compared with body lice, head lice from all six centres were significantly different in their response (P < 0.0001) to permethrin, phenothrin and malathion after 2-h exposure tests. There were significant differences in louse acetylcholinesterase activity in body lice, and head lice collected in Loughborough and Bristol in the presence or absence of carbaryl (P < 0.001), indicating enzyme inhibition. However, the difference for lice from Leeds was not significant (P = 0.363) suggesting that the enzyme was resistant to carbaryl. Eighty-nine per cent of children treated in Leeds with carbaryl were cured compared with 100% in Bristol. CONCLUSIONS: The data suggest head lice resistance is present in many parts of England to over-the-counter products containing synthetic insecticides (permethrin, phenothrin and malathion). They further suggest that resistance is starting to develop to carbaryl in head lice in Leeds and that extensive use of this product would lead to significant resistance.     

A randomized,assessor‐blind,parallel‐group,multicentre, phase IV comparative trial of a suffocant compared with malathion in the treatment of head lice in children

Background/Objectives: There are concerns about the effectiveness of head lice treatments because of increasing resistance and safety. This trial compared the safety and efficacy of a suffocant‐based head lice treatment to malathion in children. Methods: The trial used strict entry criteria, standardized treatment and assessment regimens, sibling treatment where appropriate and a primary efficacy end‐point defined as the absence of live head lice. Results: A total of 216 children were enrolled. One hundred and sixty‐nine were per‐protocol. The suffocant was significantly more effective than malathion for the intention‐to‐treat population (53.9% vs 40.4% louse‐free, unadjusted P = 0.052; adjusted P = 0.024), as well as for the per‐protocol population (57.8% vs 43.0% louse‐free, unadjusted P = 0.054; adjusted P = 0.045). Adverse events were limited to itching or stinging and there were no serious or systemic adverse events. Repeat insult patch testing with the suffocant resulted in no adverse reactions. In vitro tests confirmed that the suffocant is a potent ovicide and pediculicide with 100% mortality of eggs and lice following a 20‐min contact time. Conclusions: The suffocant is shown to be significantly more effective in eliminating head lice than malathion in children, while being associated with a low incidence of mild, transient adverse events.     

皮肤镜诊断阴虱1例

 报告皮肤镜诊断阴虱1例。 患者男,48岁,因“外阴瘙痒1个月”就诊。皮肤科专科检查：阴毛及双侧腋毛区可见红斑及丘疹,见点状出血及血痂,部分毛发根部可见浅褐色、大小不超过1 mm的寄生物附着,毛干上可见大量褐色虫卵。皮肤镜检查：可见多个寄生虫,虫体扁平似螃蟹状,虫体腹部中间见暗褐色区域。毛干上附着较多未孵化的椭圆形褐色虫卵,以及透明的虫卵空壳。治疗：10%硫软膏外用,口服依巴斯汀片10 mg, 1次/d。1个月后复诊,外阴及腋下未见虫体及虫卵,瘙痒消失。     

Persistent head lice following multiple treatments: evidence for insecticide resistance in Pediculus humanus capitis

Viable head lice were found on the scalps of two family members following multiple topical insecticide treatments. The possibility of reinfestation had been reliably excluded. Persistent infestation could be diagnosed only after cutting the hair and combing repeatedly, which allowed visualization of juvenile (nymphal) and adult lice. Insecticide-resistant headlouse infestations are probably much more common than is generally realised and may persist unnoticed, so that more aggressive approaches will be needed to eradicate these ectoparasites from individuals and communities.     

Prevalence of head lice infestation and pediculicidal effect of permethrine shampoo in primary school girls in a low-income area in southeast of Iran

Background

Head lice infestation is a common public health problem that is most prevalent in primary school children throughout the world, especially in developing countries including different parts of Iran. This study aimed to determine the prevalence and risk factors associated with head lice infestation and pediculicidal effect of 1% permethrin shampoo in primary schools girls of Bashagard County, one of the low socioeconomic areas in southeast of Iran.

Methods

In this interventional study six villages with similar demographical situations were selected and randomly assigned into intervention and control areas. In each area 150 girl students aged 7–12 years were selected randomly and screened for head lice infestation by visual scalp examination. In intervention area, treatment efficacy of 1% permethrin shampoo was evaluated via re-examination for infestation after one, two, and three weeks. Pre-tested structured questionnaire was used to collect data on socio-demographic and associated factors of head lice infestation.

Results

The prevalence of head lice infestation was 67.3%. There was significant association between head lice infestation and school grade, family size, parents’ literacy, bathing facilities, frequency of hair washing, and use of shared articles (p < 0.05). The effectiveness of 1% permethrin shampoo for head lice treatment was 29.2, 68.9, and 90.3% after the first, second, and third weeks, respectively.

Conclusion

The head lice infestation is a health problem in primary school girls of Bashagard County. Improvement of socioeconomic status and providing appropriate educational programs about head lice risk factors and prevention can be effective for reduction of infestation in this area.

Trial registration

This trial has been registered and approved by Hormozgan University of Medical Sciences ethical committee (Trial No.764). Trial registration date: March 17 2014.

     

Getting ahead of head lice

Dermatologists are the nominal experts in the management of head lice in Australia, yet many dermatologists infrequently treat patients with this condition. Most people are managed in the community by school nurses, local council health officers, pharmacists, paediatricians or general practitioners. Only a small number will present to the dermatologist and commonly these patients will have tried a variety of treatments and failed to respond. Resistance is reported to all of the currently available insecticide treatments and this makes management of this common community-acquired infestation more involved.     

The darker side of head lice infestations

Head lice (Pediculus humanus capitis) infestations are prevalent among young children and generally not considered a health hazard. Although massive chronic head lice infestations have been documented in paleo medical literature, their association with severe iron deficiency anemia has been rarely discussed in modern medicine. A recently published case implicating a head lice infestation as the cause of death of a 12-year-old girl brings this topic to the fore. This contribution discusses the available information concerning the circumstances under which this girl died and the ongoing criminal investigation as a springboard for discussion of how head lice infestations may serve as forensic and legal evidence and as a warning sign of mental illness, abuse, neglect, and rape.     

Treatment of head pediculosis. Comparative studies of a shampoo containing 0,33% Pyrethrum extract and shampoo containing 1% malathion

The insecticidal effect was tested of a shampoo with 0.33% of pyrethrum extract and a shampoo with 1% malathion. The study was carried out in 222 patients and better results were observed with the pyrethrum shampoo which required only one application.     

High in vitro efficacy of Nyda® L, a pediculicide containing dimeticone

BACKGROUND: The therapy of pediculosis remains a common problem in clinical practice. As resistance to commonly used chemical pediculicides is constantly increasing, there is a need for new effective compounds. STUDY DESIGN: The efficacy of Nyda L, a new pediculicide containing a high concentration of dimeticone, was assessed in an in vitro trial and compared with three reference products (Hedrin containing 4% dimeticone, Lyclear containing 1% permethrin, and Prioderm containing 1% malathion) and a negative control group. Head lice were collected from heavily infested patients in a resource-poor community in Northeast Brazil, where no resistance against pediculicides has been reported thus far. In each of the five groups, 50 adult fully vital lice were tested. We used a dip test (immersing head lice in the undiluted products for 3 min, washing off products after 20 min). Using predefined criteria for mortality, the lice were monitored at different points in time, for a period of 24 h. RESULTS: Nyda L and Prioderm killed all head lice already after 5 min. The efficacy of Nyda L was better than of Lyclear. Lice treated with Hedrin resurrected after several hours and did not show a significantly higher mortality compared with the control group after 24 h. CONCLUSION: Nyda L can be regarded as a very efficacious pediculicidal compound, killing all lice in vitro within 5 min.