Scabies
28848
225604285
2008-07-14T14:48:41Z
RDBrown
539176
/* Topical */ Add PMID
{{for|scabies in dogs|mange}}
{{Mergefrom|Sarcoptes scabiei|date=December 2007}}
{{DiseaseDisorder infobox |
Name = Scabies |
Image = |
Caption = |
ICD10 = {{ICD10|B|86||b|85}} |
ICD9 = {{ICD9|133.0}} |
ICDO = |
OMIM = |
DiseasesDB = 11841 |
MedlinePlus = |
eMedicineSubj = derm |
eMedicineTopic = 382 |
MeshID = D012532 |
}}
'''Scabies''' is a transmissible [[Parasitism|ectoparasite]] [[skin]] [[infection]] characterized by superficial [[burrow]]s, intense pruritus (itching) and [[secondary infection]]. The word ''scabies'' comes from the [[Latin]] word for "scratch" (scabere).
==Etiology==
[[Image:Canine scabies mite.JPG|thumb|right|''Sarcoptes scabiei var. canis'' (dog scabies mite)]]
Scabies is [[etiology|caused]] by the [[mite]] ''[[Sarcoptes scabiei]]'', variety ''hominis'', as shown by the Italian biologist [[Diacinto Cestoni]] in the 18th century. It produces intense, itchy skin [[rash]]es when the impregnated female tunnels into the [[stratum corneum]] of the skin and deposits [[egg (biology)|eggs]] in the burrow. The [[larva]]e, which hatch in 3-10 days, move about on the skin, [[ecdysis|molt]] into a "[[nymph (biology)|nymphal]]" stage, and then mature into adult mites. The adult mites live 3-4 weeks in the host's skin.
The action of the mites moving within the skin and on the skin itself produces an intense itch which may resemble an [[allergic reaction]] in appearance. The presence of the eggs produces a massive allergic response which, in turn, produces more itching.
Scabies is transmitted readily, often throughout an entire household, by skin-to-skin contact with an infected person (e.g. bed partners, schoolmates, daycare), and thus is sometimes classed as a [[sexually transmitted disease]]. Spread by clothing, bedding, or towels is a less significant risk, and is almost impossible.
The symptoms are caused by an allergic reaction that the body develops over time to the mites and their by-products under the skin, thus the 8 week "incubation" period. There are usually relatively few mites on a normal, healthy person — about 11 females in burrows. Scabies are microscopic although sometimes they are visible as a pinpoint of white. The females burrow into the skin and lay eggs there. Males roam on top of the skin, although they can and do occasionally burrow. Both males and females surface at times, especially at night. They can be washed or scratched off (however scratching should be done with a washcloth to avoid cutting the skin as this can lead to infection), which, although not a cure, helps to keep the total population low. Also, humans create antibodies to the scabies mites which do kill some of them.
==Signs, symptoms, and diagnosis==
[[Image:Scabies-burrow.jpg|thumb|right|A scabies burrow under magnification. The scaly patch at the left is due to scratching of the original papule. The mite traveled from there to the upper right, where it can be seen as a dark spot at the end of the burrow.]]
A tiny mite (0.3 to 0.9 mm) may sometimes be seen at the end of a burrow. Most burrows occur in the webs of [[finger]]s, flexing surfaces of the [[wrist]]s and [[armpit]]s, the [[areola]]e of the breasts in females and on [[genital]]s of males, along the belt line, and on the lower [[buttock]]s. The face usually does not become involved in adults.
The rash may become secondarily infected; scratching the rash may break the skin and make secondary infection more likely. In persons with severely reduced [[immunity (medical)|immunity]], such as those with advanced [[HIV]] infection, or people being treated with [[immunosuppressive]] drugs like [[steroids]], a widespread rash with thick scaling may result. This variety of scabies is called '''Norwegian scabies'''.
Scabies is frequently misdiagnosed as intense [[pruritus]] (itching of healthy skin) before papular eruptions form. Upon initial pruritus the burrows appear as small, barely noticeable bumps on the hands and may be slightly shiny and dark in color rather than red. Initially the itching may not exactly correlate to the location of these bumps.
Generally diagnosis is made by finding burrows - which often may be difficult because they are scarce, and because they are obscured by scratch marks. If burrows are not found in the primary areas known to be affected, the entire skin surface of the body should be examined.
The suspicious area can be rubbed with ink from a fountain pen or alternately a topical tetracycline solution which will glow under a special light. The surface is then wiped off with an alcohol pad; if the person is infected with scabies, the characteristic zigzag or S pattern of the burrow across the skin will appear.
When a suspected burrow is found, diagnosis may be confirmed by [[microscopy]] of surface scrapings, which are placed on a slide in [[glycerol]], [[mineral oil]] or immersion in oil and covered with a coverslip. Avoiding [[potassium hydroxide]] is necessary because it may dissolve fecal pellets. Positive diagnosis is made when the mite, [[ova]], or fecal pellets are found.
==Domestic animals==
[[Image:Scabies puppy.jpg|thumb|left|Puppy with Scabies (Sarcoptic mange)]]Many domestic animals have their own species of Sarcoptes mites. Though all can transiently affect humans,<ref>{{cite journal|author=Chakrabarti A|title=Some epidemiological aspects of animal scabies in human population|journal=Int J Zoonoses|year=1985|volume=12|issue=1|pages=39–52|pmid=4055268}}</ref><ref>{{cite journal|journal=Clin Infect Dis|title=A papulovesicular rash in a farmer and his wife|author=Ulmer A, Schanz S, Röcken M, Fierlbeck G|year=2007|volume=45|issue=3|pages=395–96|pmid=17599314|doi=10.1086/519434}}</ref> the mites that cause scabies in animals cannot reproduce on the human body and will die within a few days.[http://www.cdc.gov/ncidod/dpd/parasites/scabies/factsht_scabies.htm#how] The most frequently diagnosed form is Sarcoptic [[mange]] in dogs. In dogs and other animals, scabies produces severe itching and secondary skin infections. Affected animals often lose weight and become unthrifty.
==Compromised immune systems==
[[Image:Norwegian Scabies in Homeless AIDS Patient.jpg|thumb|Norwegian scabies in homeless AIDS patient]]
People with compromised immune systems may not develop antibodies to the mites and may develop crusted Norwegian scabies. In this case, many form scabs or develop very red skin especially in the elderly and the mentally handicapped where white or gray crusted areas develop with little itching and little or no red bumps and mite population numbers rise to thousands in AIDS patients {{Fact|date=February 2007}}. These cases require additional treatment options to ensure a complete kill. Ivermectin is a single oral treatment of choice in these patients combined with any other topical treatment.
==Gallery of scabies infections==
<gallery>
Image:Acarodermatitis_Fuß.jpg|Scabies on the Foot
Image:Acarodermatitis_Arm.jpg|Scabies on the Arm
Image:Acarodermatitis_Hand.jpg|Scabies on the Hand
Image:Acarodermatitis_Finger.jpg|Scabies of the Finger
</gallery>
===Evolution of infection===
<gallery>
Image:ScabiesD04.jpg|Day 4
Image:ScabiesD08.JPG|Day 8 '''(treatment begins)'''
Image:ScabiesD12.JPG|Day 12 '''(under treatment)'''
Image:ScabiesHealed.JPG|Healed
</gallery>
==Treatment==
===Medications===
====Topical====
* [[Permethrin]]<ref>The topical medication of choice is 5% permethrin because it is safe for all age groups.{{cite journal | author=Scheinfeld NS| title=Controlling scabies in institutional settings: a review of medications, treatment models, and implementation. | journal=Amer J Clin Dermatol | year=2004 | volume=5 | issue=1 | pages=31–7 |pmid=14979741 }}</ref>: Another pesticide, lacks carcinogenic and teratogenic testing in humans although animal tests showed no signs of carcinogenic or teratogenic effects. Toxicity may resemble allergic reactions.<ref>http://npic.orst.edu/factsheets/permethrin.pdf</ref>
* Eurax (USP [[Crotamiton]])<ref>http://www.nlm.nih.gov/medlineplus/druginfo/uspdi/202170.html</ref>
* [[Malathion]] Applied for 24 hours effective in killing adults and eggs.
* [[Lindane]] (Kwellada): For use with patients where permethrin has failed or is contraindicated.<ref>[http://www.fda.gov/cder/drug/infopage/lindane/lindanePHA.htm FDA Public Health Advisory: Safety of Topical Lindane Products for the Treatment of Scabies and Lice<!-- Bot generated title -->]</ref>
::Lindane is FDA approved as safe and effective when used as directed for the second-line treatment for both scabies and lice. Serious side effects are rare and have almost always resulted from product misuse.<ref>U.S. Food and Drug Administration (FDA). Lindane Post Marketing Safety Review. Posted 2003. Available at: http://www.fda.gov/cder/drug/infopage/lindane/lindaneaeredacted.pdf. </ref><ref name="fda">http://www.fda.gov/cder/foi/label/2003/006309lotionlbl.pdf.</ref> Lindane is registered for use in 50 countries, with restricted-use status in 33 of these countries.<ref name="fda"/><ref>Commission for Environmental Cooperation. North American Regional Action Plan (NARAP) on lindane and other hexachlorocyclohexane (HCH) isomers. November 30, 2006.</ref> The latter includes the U.S. and Canada, which support public health uses of pharmaceutical lindane but no longer allow agricultural applications.<ref name="fda"> </ref><ref>U.S. EPA. Assessment of lindane and other hexachlorocyclohexane isomers. February 8, 2006</ref> Lindane should be washed off with warm, and not hot, water to avoid absorption through the skin.<ref>Medication Guide Lindane Lotion USP, 1%. Updated March 28, 2003. Available at: http://www.fda.gov/cder/drug/infopage/lindane/lindaneLotionGuide.htm. </ref> Five to –10% sulfur ointments are considered historical.
* 10% sulfur ointment: Can be used in pregnant women and infants under two months of age. It is available over-the-counter.
====Oral====
A single dose of [[ivermectin]] has been reported to cure scabies. In 1999, a small scale test comparing topically applied Lindane to orally administered ivermectin found no statistically-significant differences between the two treatments.<ref>[http://www.aafp.org/afp/20000115/tips/15.html Efficacy and Safety of Therapy for Human Scabies Infestation - January 15, 2000 - American Academy of Family Physicians<!-- Bot generated title -->]</ref>
===Preventing reinfestation===
All family and close contacts should be treated at the same time, even if [[asymptomatic]]. Cleaning of environment should occur simultaneously, as there is a risk of reinfection. Therefore it is recommended to wash and hot iron all material (such as clothes, bedding, and towels) that has been in contact with scabies infestation.
Cleaning the environment should include:
* Vacuuming floors, carpets, and rugs.
* Disinfecting floor and bathroom surfaces by mopping.
* Cleaning the shower/bath tub after each use.
* Daily washing of recently worn clothes, towels and bedding in hot water, drying in a hot dryer and steam ironing.
* Consistently rubbing antibacterial lotion on infected areas.
* Trying to keep infested areas covered by clothing or band aids.
* Avoid contact with anus or genital areas, if infected, permanent damage may be caused
===Itchiness during treatment===
Options to combat itchiness include [[antihistamine]]s such as [[cetirizine]]. Prescription: [[Doxepin]] (Sinequan - oral or Zonalon - topical) or Hydroxine.
==References==
===Notes===
{{reflist|2}}
===Resources===
*''The Merck Manual of Diagnosis and Therapy'', 17th edition, 1999
*''Clinician's Pocket Reference'', 9th edition, 2002
*''Taber's Cyclopedic Medical Dictionary'', 17th edition, 1993
*[http://www.cdc.gov/ncidod/dpd/parasites/scabies/factsht_scabies.htm United States Centers for Disease Control and Protection]
*[http://mednet3.who.int/EMLib/DiseaseTreatments/DiseaseTreatments.aspx?DiseaseID=193 World Health Organization Essential Medicines Library]
*[http://www.ashastd.org/learn/learn_scabies_facts.cfm American Social Health Association]
*{{cite journal | author=Chosidow O | title=Scabies | journal=New Engl J Med | volume=354 | pages=1718–1727 | issue=16 | doi=10.1056/NEJMcp052784 | year=2006 | pmid=16625010 }}
*[http://www.nlm.nih.gov/medlineplus/druginfo/medmaster/a682651.html MedlinePlus Drug Information: Lindane]
*[http://www.dhs.ca.gov/dcdc/disb/pdf/Scabies%20Guide.pdf Prevention and control of scabies in california long term care facilities]
==See also==
*[[Lindane]]
*[[Crab louse]]
*[[Head louse]]
==External links==
*[http://www.aad.org/public/publications/pamphlets/common_scabies.html American Academy of Dermatology pamphlet on Scabies]
*[http://www.headlice.org/faq/scabies.htm Scabies FAQ from the National Pediculosis Association]
<!--[[it:Sarcoptes scabiei]] should link to [[:it:scabbia]] when the latter is made...-->
{{Pediculosis, acariasis and other infestations}}
[[Category:Parasitic diseases]]
[[Category:Infectious skin diseases]]
[[Category:Acari]]
[[af:Scabies]]
[[ar:جرب]]
[[ay:Qarachi]]
[[ca:Sarna]]
[[cs:Svrab]]
[[da:Fnat]]
[[de:Krätze]]
[[et:Sarkoptoos]]
[[es:Sarna]]
[[eo:Skabio]]
[[fr:Gale]]
[[id:Kudis]]
[[it:Scabbia]]
[[he:גרדת]]
[[lb:Krätz]]
[[hu:Rühösség]]
[[nl:Schurft (mens)]]
[[ja:疥癬]]
[[no:Skabb]]
[[pl:Świerzb]]
[[pt:Sarna]]
[[ru:Чесотка]]
[[fi:Syyhy]]
[[sv:Skabb]]
[[vi:Bệnh ghẻ]]
[[tr:Uyuz]]
[[zh:疥疮]]