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Scabies - Background information
What is it?
- Scabies is an intensely itchy skin infestation caused by the human parasite Sarcoptes scabiei [Johnston and Sladden, 2005].
- The main symptoms of scabies are probably caused by an immune response to the mites and their saliva, eggs, or faeces [Flinders and De Schweinitz, 2004; Johnston and Sladden, 2005]. Both immediate and delayed-type hypersensitivity are probably involved [Burns, 2004].
- A person with scabies has an average of 12 mites [Johnston and Sladden, 2005]. However, neglected children in under-privileged communities may have hundreds of mites [Heukelbach and Feldmeier, 2006].
- The adult female mite measures approximately 0.4 mm by 0.3 mm, and the adult male is smaller measuring 0.2 mm by 0.15 mm. The body is creamy white and has bristles and spines on its dorsal surface. There are four pairs of legs [Burns, 2004].
- Crusted scabies (Norwegian scabies) is a hyperinfestation, with thousands or millions of mites present in exfoliating scales of skin. It develops as a result of an insufficient immune response by the host, and presents as a hyperkeratotic skin disorder resembling psoriasis [Heukelbach and Feldmeier, 2006].
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