Clinical update on resistance and treatment of pediculosis capitis

Comparison of Pediculicides A study compared 0. Table 1 Treatment of pediculosis capitis: evidence based. Alternative Medicine Essential oils have been widely used in traditional medicine for the eradication of head lice, but because of the variability of their constitution, the effects may not be reproducible. Therapies with Physical Mechanisms Occlusive agents These are applied to suffocate the lice. Desiccation The Louse Buster, a custom-built machine uses one min application of hot air. Manual removal Removal of nits immediately after treatment with a pediculicide is not necessary to prevent spread, because only live lice cause an infestation.

Pediculicide Resistance The true prevalence of resistance to a particular pediculicide is unknown, and may vary from region to region. What is new? References 1. Clinical guidelines: Developing guidelines. Ten thousand years of head lice infection. Parasitol Today. Pediculosis capitis. J Pediatr Health Care. Feldmeier H. Pediculosis capitis: New insights into epidemiology, diagnosis and treatment.

Khokhar A. A study of pediculosis capitis among primary school children in Delhi. Indian J Med Sci. Comparative efficacy of treatments for pediculosis capitis infestations. Arch Dermatol. Comparative in vitro pediculicidal efficacy of treatments in a resistant head lice population on the US.

Guidelines for the treatment of resistant pediculosis. Contemp Pediatr. Therapy for head lice based on life cycle, resistance, and safety considerations.

Permethrin resistance in the head louse Pediculus capitis from Israel. Med Vet Entomol. A resistance of head lice [ Pediculus capitis ] to permethrin in Czech Republic.

Cent Eur J Public Health. Differential permethrin susceptibility of head lice sampled in the United States and Borneo. Arch Pediatr Adolesc Med. Permethrin-resistant human head lice, Pediculus capitis , and their treatment. Head lice. J Pediatr. Comparison of pediculicidal and ovicidal effects of two pyrethrin-piperonyl-butoxide agents.

Clin Ther. Burkhart CG. Relationship of treatment-resistant head lice to the safety and efficacy of pediculicides. Mayo Clin Proc. Efficacy of a reduced application time of Ovide lotion [0. Pediatr Dermatol. Evidence for double resistance to permethrin and malathion in head lice. Br J Dermatol. Bailey AM, Prociv P. Persistent head lice following multiple treatments: Evidence for insecticide resistance in Pediculus humanus capitis [letter] Australas J Dermatol. Meinking T, Taplin D.

Pediatric Dermatology. Tenenbein M. Seizures after lindane therapy. J Am Geriatr Soc. Fischer TF. Lindane toxicity in a year-old woman. Ann Emerg Med. Shacter B. Treatment of scabies and pediculosis with lindane preparations: An evaluation. J Am Acad Dermatol. Rasmussen JE. The problem of lindane. Lindane Toxicity: A comprehensive review of the medical literature.

Burgess IF. Human lice and their management. Adv Parasitol. The story of lindane resistance and head lice. Int J Dermatol. US Food and Drug Administration. FDA public health advisory: Safety of topical lindane products for the treatment of scabies and lice [ Google Scholar ]. American Academy of Pediatrics.

Pediculosis capitis [head lice] pp. Lice: Resistance and treatment. Dodd CS. Interventions for treating headlice. Cochrane Database Syst Rev. A key to formulating an effective treatment regimen is recognizing that available treatments destroy lice, but do not reliably destroy eggs. Repeat treatment typically is required for complete eradication, timed on the life cycle of the louse. Trials that use single-dose treatment may not fully evaluate the true effectiveness of the drugs.

In the United Kingdom, malathion is used often and resistance is common. Although lindane still is available by prescription in most of the United States, the U.

It is not available in California or in the United Kingdom. Lindane may be used as a second-line agent in adults, but should not be used in children, older persons, or adults weighing less than lb 50 kg. It should not be used unless all other agents are contraindicated or ineffective. It should not be reapplied in any situation. This product prevents lice from closing their respiratory spiracles, which causes permanent obstruction and results in death.

In early , the FDA approved a pediculicidal topical suspension agent, spinosad 0. Ivermectin Stromectol is an oral anti-parasitic that has demonstrated effectiveness in clinical trials, but is not FDA-approved for the treatment of pediculosis. A trial of patients older than two years compared ivermectin mcg per kg with malathion 0.

The results showed that 95 percent of patients taking ivermectin were lice-free at day 15, compared with 85 percent of patients using malathion. The authors suggest that ivermectin may be an appropriate second-line therapy when resistance to topical treatments is documented. Wet combing involves moistening the hair with commercially available leave-in conditioner and systematically combing the hair from root to tip with a lice comb. Wet combing alone for treating pediculosis does not have adverse effects, and often is preferred by parents wanting to avoid a chemical treatment; however, it can be time consuming depending on hair length and thickness.

Combing should be done every three days for two weeks. Cure rates vary considerably 47 to 75 percent , but may be improved by increasing the duration of combing to 24 days. Delivery of hot air to kill lice by desiccation has been attempted by numerous investigators with mixed results. Research is ongoing on this minimally invasive treatment option. Cetaphil Gentle Skin Cleanser has been studied as a dry-on, suffocation-based pediculicide lotion with a demonstrated eradication rate of 95 percent, although there is question about the design and rigor of the study.

Treatment of pubic lice is similar to that of head lice. A pediculicide is not always necessary. Scabies is a common public health problem, affecting approximately million persons worldwide. The arthropod is an ovoid organism. The female is approximately 0. After mating on the skin surface, the male mite dies and the female mite begins to burrow under the skin, where she lays eggs for four to six weeks. Female mites can travel up to 2. After exposure, mites can penetrate the epidermis within 30 minutes.

A person with conventional scabies needs about 15 to 20 minutes of close contact to transfer the mite to another person. Although scabies is more common in young children, other predisposing factors include overcrowding, poor hygiene, poor nutritional status, homelessness, dementia, and sexual contact.

Persons with scabies typically present with an intense and generalized pruritic rash that is worse at night, with the face and neck unaffected. The primary skin lesions are inflammatory pruritic papules, pustules, vesicles, and nodules.

The pathognomonic finding is a burrow, which may not always be evident. These are most commonly found on the hands and feet or in the finger webs, and appear as short, wavy, scaly gray lines on the skin surface. The characteristic body distribution of lesions in adults is illustrated in Figure 3. Characteristic distribution of lesions in adults with classic scabies.

Burrows are more common on hands and wrists, whereas papular or nodular lesions generally are present elsewhere. Crusted scabies also called Norwegian scabies is an extremely contagious atypical form of scabies occurring primarily in patients who are older, immunocompromised, or living in close quarters. Patients may present with thick, crusted lesions on the hands and feet, nail abnormalities, generalized erythematous scaling eruptions, and scalp involvement. Because pruritus is mild or absent in this form, scabies is often misdiagnosed, leading to large nosocomial outbreaks.

In crusted scabies, thousands of mites may be present, and the risk of transfer is greater. Scabies may be diagnosed with a history of pruritus, rash in the typical distribution, and history of itching in close contacts.

Finding mites, eggs, or fecal pellets provides definitive diagnosis. The most common method of examination for mites is skin scraping. Scrapings should be taken from nonexcoriated burrows, papules, or vesicles by applying a drop of mineral oil to the skin, scraping laterally across the lesion using a scalpel, and transferring the oil and skin scraping to a slide.

A positive test result reveals mites, eggs, or fecal pellets Figure 5. In contrast to lice, there are fewer randomized controlled trials of products to treat scabies. Most studies were conducted using lindane as the comparator.

Patients should be educated that they may continue to have itching for up to two weeks, even after appropriate and effective treatment. There is evidence for empiric treatment if a patient presents with pruritus and lesions typical of scabies in at least two body sites, or if there are others in the patient's household with pruritus. A single dose of oral ivermectin at mcg per kg and repeated at day 14 also is considered an option for first-line treatment of classic scabies by the CDC, although cost and availability often relegate it to second-line therapy if treatment with topical permethrin is unsuccessful.

For items that cannot be machine washed, isolation in a plastic bag for at least 72 hours is sufficient. Other environmental measures such as pesticide sprays or powders are not recommended. Vacuuming may be helpful, although there is little direct evidence of benefit. Crusted scabies represents a treatment challenge. It often is longstanding because of misdiagnosis. Clinical trials are limited. Data Sources: A PubMed search was conducted in Clinical Queries using the key terms lice and scabies, and using the limits human and English.

The blood of a nymph, called hemolymph, isclear. The red color of a recently fed nymphis due to the host's blood meal. Nymphs areextremely small, at about the size of a point font period at the end of a sentence. Their transparency and size make newlyhatched nymphs extremely difficult to seeduring examination. Nits, the eggs laid bylice, are attached to the hair shaft with anadhesive substance. Since they are stationary,nits are actually easier to find andremove than nymphs.

The feeding structures of lice are complex,including the haustellum, a proboscis-liketube with teeth, which is used to piercethe host's skin, and a cibarial pump thatdraws blood through the haustellum. Theteeth of the haustellum anchor it to thehost's skin while the louse feeds.

There are 3stylets within the haustellum, as shown in Figure 2. Two of the stylets inject a substanceto make feeding easier, including ananticoagulant and a vasodilator, while thethird is used to draw back the blood to feed. The mouthparts retract when the louse isnot feeding. There is no information to date suggestingthat head lice spread disease, but research isongoing. Body lice are known to spread diseasessuch as typhus, relapsing fever, andtrench fever, a reemerging disease in theUnited States caused by Information about disease transmissionwas derived from colonies of body licethat have been maintained and studied onrabbits, but no similar colony of head liceexists.

Although attempts have been made,head lice will feed only on human blood. Over the last 2 decades, pediculicidepackaging and formulations have changed,contributing to resistance.

Theydid not realize that plastic affected the formulation,decreasing its efficacy. Neither product is asefficacious as it was during studies conductedin the s.

Another contributor to resistance is thedilution of pediculicides that are designed tobe applied to wet, towel-dried hair. Theamount of water left in towel-dried hair isvery subjective, and some hair types naturallyretain more water than others.

Patientsalso may apply too little product, oftenbecause more than 1 family member isinfested. Conserving product also conservescosts.

When pediculicides are diluted or areused too sparingly, lice are exposed to sublethaldoses and eventually develop resistance. Conversely, patients may use toomuch product or may use it as preventivetreatment when there is no lice infestation. Resistance may develop from overexposureto pediculicides. An in vitro study was conducted in April to assess the extent to which the efficacyof pediculicides had changed since theearly s because of alterations in theirformulations.

Results fromthis study were compared with an earlier study evaluating pediculicide efficacyin Panama. There wasno change from to in the rankingof malathion 0. A follow-up study wasconducted from July through November to assess the efficacy of the same 5products in killing lice harvested from peoplein a south Florida clinic. Yallew, and B. Notes, vol. Gholamnia Shirvani, F. Amin Shokravi, and M. Nazari, R. Goudarztalejerdi, and M. Karimah, R. Hidayah, and A. Kokturk et al.

Khakshoor-gharehsoo and N. Junco, and R. Saude Publica, vol. Davarpanah, A. Kazerouni, H. Rahmati, R. Neirami, H. Bakhtiary, and M. Tebruegge, A. Pantazidou, and N. Feldmeier H. Pediculosis capitis: New insights into epidemiology, diagnosis and treatment. Wolf and B. Kamiabi and F.

Yousefi, F. Shamsipoor, and Y.