Head lice infestation

Detection of head lice infestation is based on identifying lice by detection combing. Head lice detection cannot be solely based on an itchy scalp because not all children with head lice have the symptom. Furthermore, itchiness is caused by an allergic reaction to the lice, which may develop a few weeks after the infection and can persist for some time after eradication. Infestation is equally likely to occur in clean or dirty hair. 

Preparations of three insecticidal compounds are available without prescription to treat head lice infestation. 

Which one of the following, used for treatment of head lice infestation, is a POM ... 

The pyrethrins represent a group of six closely-related monoterpene esters and are invaluable insecticidal substances isolated from pyre-thrum flowers, such as Chrysanthemum cinerariaefolium, and several other species in the Asteraceae family. Pyrethrins are indicated for treatment of skin parasites, such as head lice. They block sodium channel repolarization of the arthropod neurons, which leads to parasite paralysis and death. Permethrin is also used to treat head lice infestation. However, the growing resistance of head lice to pyrethrin and permethrin is becoming a serious concern [88]. 

Figure 2. Fluctuation of head lice infestations reported by the Ministry of Health and Welfare.

Meinking TL, Mertz-Rivera K, Villar ME, Bell M. Assessment of the safety and efficacy of three concentrations of topical ivermectin lotion as a treatment for head lice infestation. Int J Dermatol 2013 52 106-12. 

Head louse infestations periodically cause disruptions at schools aii over the world. The treatment with pyrethrins and PBO is relatively cheap, and effective. The most common formulations contain either 0.15% or 0,3% pyrethrins synergized with 3.0% PBO formulated into non foaming shampoos (water- based pm-sized emulsions) that are applied directly to the affected area and repeated after i week to kill any newly hatched lice. The pediculicidal and ovicidal efficacy of synergized pyrethrins arc enhanced in shampoo formulations as a result of the surface-tension-lowering action of the formulation and are preferable to direct applications of lotions. 

Burgess, 1. R, Brunton, E. R., Burgess, N. A. 2010. Clinical trial showing superiority of a coconut and anise spray over permethrin 0.43% lotion for head louse infestation, 1SRCTN96469780. Ear. J. Pediatr. 169(l) 55-62. 

Kazan L, Berg JE, Bowman JP, Murray JV, Ryan WG. Pharmacokinetics and safety of 0.5% ivermectin lotion for head Louse infestations. Pediatr Dermatol 2013 30(3) 323-8. 

Phthiriasis palpebrarum is an imcommon eyelid infestation by Phthiruspubis (crab louse) and, less commonly, by the Pediculus bumanus species, P. humanus var. capitis (head louse) and P humanus var. corporis (body louse). The term pediculosis refers to infestation by the two P humanus species and should not generally be used when referring to eyelid manifestations. 

Pediculosis caused by Pediculus capitis, the human head louse, is the most prevalent parasitic infestation of humans worldwide, especially among school children of 3-12 years old (7). More Uian 6-12 million people in the United States (US) are estimated to have pediculosis. Synq>toms of infestations are relatively mild, but the social, mental and economic consequences are substantial. Pediculosis is not widely tolerated in the US and is repeatedly treated by a variety of over-the-counter pediculicides, which are exclusively limited to those containing pyrethrin or permetfarin as active ingredients. Because these pediculicides share a common mechanism of action on the voltage-sensitive sodium channel in the nervous system of insects (2), dieir repetitive and continued use has imposed a high pressure for the selection of resistant louse populations. 

Eggs of the louse were found attached to the base of feathers on the heads and necks of adult birds (Boyd, 1951). These eggs were removed and placed in covered, humidified petrl dishes. Adult fowl mites were collected from infested nest boxes by placing a strip of paper amidst a swarm of mites, allowing the mites to board the paper, then depositing the mites and paper into a vial. Upon return to the laboratory, the mites were transferred to covered, humidified petri dishes. 

---