الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Arthropods include a number of species that hold an important place in medical science by reason of their ability to function directly as agents of human disease or discomfort. Arthropods produce their effects on the skin by a variety of mechanisms. Scabies is a parasitic dermatosis with a worldwide distribution.
Scabies is usually contracted by close personal contact such as nursing an infested patient, playing with an infested child or sleeping together and infrequently by the use of contaminated towels, bed linen and clothing. Demodex folliculorurn, the follicle mite, is an obligate parasite of the human pilosebaceous follicle. Although most people are infested with these mites, only a small number develop the clinical symptoms of demodicosis. Trombiculids are parasitic as larvae. There they pierce the skin with their cheliceral clows and inject saliva which has cytolytic properties, into the epidermis. Myiasis is the infestation of live human and vertebrate animals with dipterous larvae which, at least for a certain period, feed on the host’s dead or living tissue, liquid body-substances, or ingested food.Lice are obligatory parasites surviving on blood meals obtained from the host, with their mouthparts modified to enable piercing and sucking. Insect bite:Cutaneous symptoms to mosquito bite include immediate wheal and flare reactions and delayed bite papule, which tend to be more severe at the onset of mosquito season. Systemic reaction to mosquito bites are, however, very rare.Bites of phlebotamine Sandflies often cause considerable annoyance and discomfort.Bites of Simuliidae, which may be very numerous, are on the exposed skin.Ceratopogonidae bites on exposed extremities, around the head and neck or even in between the head hairs and producing irritating local lesions.Tabanidae bite is deep and painful and may produce an ugly wound that heals slowly; it frequently becomes secondarily infected. Flea bite usually provokes popular urticaria in a sensitized individual. The bites of predatory species of Triatoma are purely defensive and are usually extremely painful. On the other hand, the bite of the blood sucking triatominae, are painless. Bedbug bite lesions range from erythematous pruritic macules in previously unexposed patients, to pruritic papules, wheals, vesicles, or bullae in sensitized patients.One of the more important etiological factors of allergies is house dust mites.