Scabies Questions & Answers

Updated: Jun 07, 2019
  • Author: Megan Barry, MD; Chief Editor: Dirk M Elston, MD  more...
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Questions & Answers

Overview

What is scabies?

What is a pathognomonic sign of scabies, and which areas of the body are commonly affected?

Which areas of the body are commonly affected by scabies in elderly patients, and which areas are commonly affected in infants and small children?

What is the clinical appearance of scabies in adults?

What is the presentation of nodular scabies?

What is the presentation of crusted scabies?

How are secondary lesions associated with scabies characterized?

How is scabies diagnosed?

What is the role of biopsy in the diagnosis of scabies?

How is scabies diagnosed in the absence of typical clinical findings?

What is the standard treatment for scabies?

How is pruritus in scabies treated?

How are crusted scabies treated?

What is scabies, and why is diagnosis often delayed?

What is the worldwide incidence of scabies, and what are the factors that contribute to its prevalence?

Which populations have the highest prevalence of scabies, and who is at highest risk for crusted scabies?

How is scabies transmitted from person to person?

What are the characteristics of the S scabiei hominis mite that causes scabies in humans?

What is the life cycle of a scabies mite?

What is the life cycle of the S scabiei var hominis (scabies) mite?

What is the pathophysiology of classic scabies infection?

Which type of cells are responsible for persistent itching in scabies, and which type of cells reduces pruritus?

What is crusted (Norwegian) scabies?

When should a diagnosis of crusted scabies be considered?

Which immune reactions are seen in patients with crusted scabies, and which are seen in classic scabies?

Which patient populations are susceptible to crusted scabies?

What is the etiology of scabies?

Can humans contract scabies from an infested animal?

Does scabies spread between different host species?

What is the clinical course of nonhuman (animal) scabies infestation in humans?

Which patient populations have the highest prevalence of scabies, and who is at risk for the crusted variant?

What are major risk factors for scabies?

What is the prevalence of scabies worldwide?

Which populations have the highest prevalence of scabies infestation?

What is the incidence of scabies?

Where is scabies most common?

How common is scabies in children?

What is the prognosis of scabies?

How long do symptoms of scabies last?

What can cause symptoms of scabies to persist?

What are the complications of scabies?

Which pyodermas have been associated with scabies?

What is the association between scabies and an increased risk of chronic kidney disease?

What is the role of other skin conditions in the development of scabies complications?

What is the role of scabies in renal failure and rheumatic heart disease?

What are the risks associated with crusted scabies?

What patient education information is available for scabies?

Presentation

What features of the patient history suggest the presence of scabies?

Which parts of an adult’s body are most commonly affected by scabies?

Which parts of an infant’s or child’s body are most commonly affected by scabies?

Which patients are susceptible to scabies in all cutaneous sites?

What happens when scabies has been misdiagnosed and treated with topical corticosteroids?

When do patients with scabies typically seek medical treatment?

Does scabies occur in outbreaks?

What is the presentation of crusted scabies?

What are the typical physical exam findings of scabies?

What is the appearance of scabies burrows, and which body areas are most affected?

Where does scabies typically present in old and young patients?

What is the clinical appearance of scabies in adults?

Do papules in scabies contain mites, and where do they typically occur?

What is the typical presentation of scabies in children and infants?

What is the presentation of nodular scabies?

What are the characteristic findings of secondary lesions in scabies?

DDX

Which conditions should be considered in the differential diagnosis of scabies?

Which conditions should be considered in the differential diagnosis of pruritus with or without rash in scabies?

Which conditions should be considered in the differential diagnosis of nodular scabies?

Which conditions should be considered in the differential diagnosis of crusted scabies?

What are the differential diagnoses for Scabies?

Workup

How is scabies diagnosed?

What is the role of biopsy in the workup of scabies?

How is scabies diagnosed in the absence of clinical findings?

What research is currently underway for a routine diagnostic test for active scabies?

What is the burrow ink test used in the workup of scabies?

How is a topical tetracycline solution used to locate mite burrows in scabies?

How are skin scrapings used in the workup of scabies?

How is superficial cyanoacrylate biopsy (SCAB) used in the workup of scabies?

How are skin scrapings used in the workup of crusted scabies?

How is the adhesive tape test used in the workup of scabies?

What is the efficacy of dermatoscopy-guided tape testing for scabies?

What are the histologic features of scabies?

What are the histologic findings of crusted scabies?

What are the histologic findings of nodular scabies?

Treatment

What is the treatment for scabies?

What is the efficacy of mass treatment of scabies?

What are the most common causes of treatment failure in scabies?

When should neonates and pregnant women be treated for scabies?

How are crusted scabies and nodular scabies treated?

How should activity be restricted in patients with scabies?

When should patients with scabies consult a dermatologist or an infectious disease specialist?

What is the drug of choice for the treatment of scabies?

How is pruritus in scabies treated?

What is the role of videodermatoscopy in the treatment of scabies?

What is the proper pharmacologic treatment of crusted scabies?

What is the appropriate follow-up for scabies treatment?

Who should receive prophylactic treatment for scabies?

What can patients do to prevent a recurrence of scabies?

How can the prevalence of scabies be reduced?

Guidelines

What are the CDC guidelines for the treatment of scabies?

What are the Japanese and German guidelines for the treatment of scabies?

Medications

What is the treatment of choice for scabies?

What is the treatment for pruritus in scabies?

How are scabies outbreaks in nursing homes and cases of crusted scabies treated?

Is drug resistance a concern in scabies treatment?

How is benzyl benzoate used in scabies treatment?

Which medications in the drug class Antiparasitic Agents are used in the treatment of Scabies?

Which medications in the drug class Topical Antibiotics are used in the treatment of Scabies?

Which medications in the drug class Corticosteroids, Topical are used in the treatment of Scabies?