WBR0417

Author	[[PageAuthor::Rim Halaby, M.D. [1], Alison Leibowitz [2] (Reviewed by Alison Leibowitz)]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Microbiology
Sub Category	SubCategory::Dermatology
Prompt	[[Prompt::Brought by his mother, a 10-year-old male presents to the physician’s office with complaints of intense itching in his hands. Physical examination reveals multiple lesions with papular eruptions in the inter-digital spaces. Burrows are also detected using ink test and special lighting. You suspect a skin infestation caused by a parasite (the parasite is displayed in the image below). Which of the following pieces of advice should you provide the patient with regarding the treatment of his condition? ]]
Answer A	AnswerA::Hand wash with water and soap that contains antibiotics is necessary
Answer A Explanation	[[AnswerAExp::Scabies is caused by a parasite, not bacteria, so hand wash alone is not sufficient for treatment of scabies.]]
Answer B	AnswerB::Replacement of soap with hypo-allergic soap is necessary
Answer B Explanation	AnswerBExp::Despite a manifestation similar to that of an allergy, scabies is not an allergic condition. Replacement of soap with hypo-allergic soap is not helpful.
Answer C	AnswerC::A psychiatric consultation for the patient is necessary
Answer C Explanation	[[AnswerCExp::Delusional parasitosis (Ekbom’s syndrome) is a form of psychosis where patients believe they are infested with parasites. In patients with Ekbom's syndrome, physical examination would not reveal any skin findings.]]
Answer D	AnswerD::Washing beddings, clothes, and furniture is necessary
Answer D Explanation	AnswerDExp::See explanation.
Answer E	AnswerE::Transparent adhesive tape applied to the anal area is necessary
Answer E Explanation	[[AnswerEExp::A scotch tape test is useful for the diagnosis of pinworms. inworms, or Enterobius vermicularis, are nematodes (roundworms) that are transmitted by egg-contaminated foods. Patients with pinworms are often treated with by bendazoles or pyrantel pamoate.]]
Right Answer	[[RightAnswer::D WBRKeyword=scabies, parasite, skin, lesions, itching, contagious, topical]]
Explanation	[[Explanation::Scabies is a skin infestation caused by the Sarcoptes scabiei. Scabies is a highly contagious condition, often transmitted by direct skin-to-skin contact. A typical manifestation of scabies is generalized intense pruritic itching, typically worst at night, which usually spares the head and face. Commonly affected areas are the inter-digital regions, elbows, axillae, buttocks, breasts, and genital region. The diagnosis of scabies is clinical, based on history and physical examination, and is often confirmed using the burrow ink test (BIT). Ink is applied to the suspected area, which is then cleaned with alcohol. When special light is applied to the area, burrows will demonstrate characteristic “zig-zag” tunnels. Blade scraping across the lateral skin and examination with light microscopy is often useful in diagnosis. Topical medications, such as permethrin, lindane, benzyl benzoate, and crotamiton, and oral ivermectin are used to treat scabies. Because scabies is highly contagious, treatments should also be administered to other household members. Washing personal items, such as clothes, towels, and beddings, is necessary for appropriate eradication. Items that cannot be washed should be placed in sealed plastic bags for at least 3-7 days until all the mites die inside. Educational Objective: Scabies, caused by the mite Sarcoptes scabiei, is a contagious disease that is often transmitted by skin-to-skin contact. Because scabies is highly contagious, treatments should also be administered to other household members. Washing personal items, such as clothes, towels, and beddings, is necessary for appropriate eradication. References: Chosidow O. Scabies. New Eng J Med. 2006;354:1718-1727]]
Approved	Approved::Yes
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