Rare Infectious Disease News

Disease Profile

Crusted scabies

Prevalence
Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.

Unknown

Age of onset

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ICD-10

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Inheritance

Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease

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Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype

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X-linked
dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.

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X-linked
recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder

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Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.

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Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.

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Not applicable

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Other names (AKA)

Norwegian scabies; Seven year itch

Summary

Crusted scabies (also called Norwegian scabies) is an infestation characterized by thick crusts of skin that contain large numbers of scabies mites and eggs. It is a severe form of scabies that occurs most often in people who have a weakened immune system or a neurological disease, the elderly, and the disabled. The symptoms of the more common form of scabies, such as itching and a rash, may be absent. Crusted scabies is very contagious and can spread both by direct skin-to-skin contact and through contaminated items such as clothing, bedding, and furniture.[1][2] It is caused by super-infestation with Sarcoptes scabiei var hominis, a mite that can only reproduce on humans. People with crusted scabies should receive quick and aggressive medical treatment for their infestation to prevent future outbreaks of scabies.[1] Ivermectin, a drug used to treat parasitic infections, is commonly used for treatment.[2]

Treatment

Crusted scabies may be particularly difficult to treat. Patients with crusted scabies may be instructed by their doctors to remove scaling skin so that topical medications can penetrate the skin more easily.[3] Repeated applications of a topical medication or combined treatment with a topical and an oral medication for several weeks or longer may be necessary.[3][4] Patients who still have signs of infection after one month may need additional treatment. Infants and pregnant women should be treated for scabies only if the benefit is determined to outweigh the risk and if the diagnosis is confirmed by biopsy.[3] 

A dermatologist or infectious disease physician should be involved in the care of the patient and those with whom they have had close contact. Treatment of crusted scabies should be done in an inpatient or residential setting, with the patient in a private room.Treatment includes oral Ivermectin and topical insecticides.

Learn more

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • You can obtain information on this topic from the Centers for Disease Control and Prevention (CDC). The CDC is recognized as the lead federal agency for developing and applying disease prevention and control, environmental health, and health promotion and education activities designed to improve the health of the people of the United States.
  • DermNet NZ is an online resource about skin diseases developed by the New Zealand Dermatological Society Incorporated. DermNet NZ provides information about this condition.
  • MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.

In-Depth Information

  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Crusted scabies. Click on the link to view a sample search on this topic.

References

  1. What is crusted (Norwegian) scabies?. Centers for Disease Control and Prevention (CDC). November 2, 2010; https://www.cdc.gov/parasites/scabies/gen_info/faqs.html#crusted.
  2. Oakley A. Scabies. DermNet NZ. 2016; https://www.dermnetnz.org/arthropods/scabies.html.
  3. Barry M. Scabies. Medscape Reference. November 18, 2015; https://emedicine.medscape.com/article/1109204-overview.
  4. Scabies. DermNet New Zealand Trust. 2016; https://www.dermnetnz.org/arthropods/scabies.html.
  5. Thoma L. Crusted scabies. DermNet NZ. June, 2016; https://www.dermnetnz.org/topics/crusted-scabies/.

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