EncyclopediaScabies

Classification and external resources

Sarcoptes scabiei

ICD-10B86.

ICD-9133.0

DiseasesDB11841

MedlinePlus000830

eMedicinederm/382emerg/517ped/2047

MeSHD012532

Scabies, also known asthe itch, is a contagiousectoparasiteskin infectioncharacterized by superficialburrowsand intensepruritus(itching).It iscausedby themiteSarcoptes scabiei.The wordscabiesitself is derived from theLatinword for "scratch" (scabere).Other names or variants of the condition includeMite,Itch Mite,Mange,Crusted Scabies,Norwegian Scabies,Sarcoptes scabiei, orThe Seven-Year Itch.Contents 1Signs and symptoms 1.1Compromised immune systems 1.2Gallery of scabies infections 1.3Evolution of infection 2Cause 3Diagnosis 4Management 4.1Medications 4.1.1Topical drugs 4.1.2Oral 4.2Public health and prevention strategies 4.3Itchiness during treatment 5Epidemiology 6History 7Animals 8Feral Animals 9See also 10References 11External links

Signs and symptoms

A scabies burrow under magnification.The scaly patch at the left is due to scratching of the original papule.The mite travelled from there to the upper right, where it can be seen as a dark spot at the end of the burrow.The characteristic symptoms of scabies infection include superficial burrows, intensepruritus(itching), a generalized rash and secondary infection.Acropustulosis, or blisters and pustules on the palms and soles of the feet, are characteristic symptoms of scabies in infants.[1]S-shaped tracks in the skin are often accompanied by small, insect-type bites called nodules that may look like pimples.[1]These burrows and nodules are often located in the crevices of the body, such as the webs of fingers, toes, feet, buttocks, elbows, waist area, genital area andaxilla, and under the breasts in women.[1]The intense itching and rash characteristic of scabies infection is caused by an allergic reaction of the body to the burrowed microscopic scabies mites.The rash can be found over much of the body, especially in immunocompromised people (HIV positive or elderly); the associated itching is often most prevalent at night.[2]Secondary infection ofimpetigo, aStreptococciorStaphylococcibacterial skin infection, may occur after scratching.Cellulitismay also occur, resulting in localized swelling, redness and fever (DermNet).In immuno-compromised, malnourished, elderly or institutionalized individuals, infestation can cause a more severe form of scabies known ascrusted scabiesor Norwegian scabies.This syndrome is characterized by a scaly rash, slight itching and thickened crusts of skin containing thousands of mites.[2]Norwegian scabies is the form of scabies that is hardest to treat.In individuals never before exposed to scabies, the onset of clinical signs and symptoms is 46 weeks after infestation.Some people may not realize that they have it for years; in previously exposed individuals, onset can be as soon as 24 days after infestation.Compromised immune systems

Norwegian scabies in AIDS patientPeople with compromised immune systems, such as people with HIV or cancer or transplant patients on immunosuppressive drugs, may be susceptible to Crusted (Norwegian) scabies.In this case the scabies go unregulated bycytotoxicT cells and spread over the whole body, except the face.These cases require additional treatment options for resolution.Ivermectinis a single oral treatment of choice in these patients combined with any other topical treatment.Gallery of scabies infectionsScabies of the footScabies of the armScabies of the handScabies of the finger

Evolution of infectionDay 4Day 8(treatment begins)Day 12(under treatment)Healed

CauseMain article:Sarcoptes scabiei

Sarcoptes scabiei var.canis(dog scabies mite)Scabies is highly contagious and can be spread by scratching, picking up the mites under the fingernails and simply touching another person's skin.They can also be spread onto other objects like keyboards, toilets, clothing, towels, bedding, furniture, and anything else that the might may be rubbed off onto, especially if a person is heavily infested.The parasite can survive up to 14 days away from a host, but often do not survive longer than two or three days away from human skin.[3]Scabies iscausedby themiteSarcoptes scabiei, varietyhominis, as shown by the Italian biologistDiacinto Cestoniin the 18th century.It produces intense, itchy skinrasheswhen the impregnated female tunnels into thestratum corneumof the skin and depositseggsin the burrow.Thelarvae, which hatch in 310 days, move about on the skin,moltinto a "nymphal" stage, and then mature into adult mites.The adult mites live 34 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 anallergic reactionin appearance.The presence of the eggs does not in fact produce more itching, that is a myth.It is rather the feces of the mites which cause the allergic reaction.Scabies can be transmitted readily throughout an entire household, by skin-to-skin contact with an infected person (e.g.bed partners, schoolmates, daycare).It can be spread by clothing, bedding, or towels.Washing clothing in very hot water and dry on high heat will help prevent the transmission.Alternatively,permethrinsprays can be used for items that cannot be laundered.The symptoms of itching and rash are caused by an allergic reaction that the human body develops over time to the mites and their by-products under the skin.As such, there is usually a 2-6 week incubation period between infestation and presentation of symptoms.However, in individuals with prior exposure to scabies, the incubation period is much shorter: as little as 14 days.[4]There are usually relatively few mites on a normal, healthy person (who is infested with scabies) 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 can also occasionally burrow.DiagnosisSigns and symptoms of early scabies infestation mirror other skin diseases, includingdermatitis,syphilis, allergic reactions, and otherectoparasitessuch asliceandfleas.[5]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 bymicroscopyof surface scrapings with scalpel or curette are placed on a slide inglycerolormineral oiland covered with a coverslip.Avoidingpotassium hydroxideis necessary because it may dissolve fecal pellets.Positive diagnosis is made when the mite,ova, or fecal pellets are found.Although this sounds simple in practice, actual detection of scabies sites is very difficult - requiring the scraping of dozens of suspicious lesions down to the superficial dermis.This will result in minor bleeding in spots.Even a negative (not finding any mites) scraping will not completely rule out scabies.Sometimes, the best diagnosis is by the history, physical findings and noticing response to effective topical treatment.The diagnosis of Crusted Scabies is not as elusive and a scraping under the fingernail is often diagnostic.

Video of thesarcoptes scabieimite.

Video of thesarcoptes scabieimite.ManagementMedications Sulphur has been used since around 25 AD to treat Scabies[citation needed].You can find bar soap with sulfur in the ranges of 1%-10% to kill scabies, it's recommended you go with 6% or above.Wash whole body once daily for 4 days.It is still recommended that you wash all clothing and bedclothes in hot water and tumble dry on hot as with Permethrin.However, this treatment is largely ineffective[citation needed].Topical drugs Permethrin5% is topical medication of choice.[6]Toxicity may resemble allergic reactions.It is usually applied to the skin before bedtime and left on for about 8 to 14 hours, then showered off in the morning.Package directions or doctor's instructions should be followed, but one application is normally sufficient to cure an infection.[7] Eurax (USPCrotamiton) This is not a cure but helps to relieve itch (pruritis)[8] Malathion: Applied for 24 hours; effective in killing both adults and eggs. Lindanelotion is approved in the U.S. for use as a second-line treatment where first-line medications like permethrin have either failed, are not well tolerated or otherwise contraindicated.[9]It is illegal in 17 other countries, and 33 more countries have restricted its use.[10][11]Though rare, serious side effects have resulted from product misuse.[12][10]The FDA has confirmed 3 deaths that all involved use of lindane not in accordance with the label, including excessive topical applications and oral ingestions.[13] There is some evidence that a 10%sulfurointment inpetroleum jellyapplied topically is effective.It is cheap and readily available over-the-counter.[14][15]It also has the advantage of being able to be used in pregnant women and infants under two months of age. Neem oilis deemed very effective in the treatment of scabies although only preliminary scientific proof exists which still has to be corroborated, and is recommended for those who are sensitive topermethrin, a knowninsecticidewhich might be an irritant.Also, the scabies mite has yet to become resistant toneem, so in persistent cases neem has been shown to be very effective.[16] Tea tree oilat 5% was only partially effective and does not seem to be a viable solution for treatment.In one study, it was more effective than commercial medications against the scabies mite in anin vitrosituation.[17]OralA single dose ofIvermectinhas been reported to reduce the load of scabies but another dose is required after 2 weeks for full eradication.In 1999, a small scale test comparing topically applied Lindane to orally administered Ivermectin found no statistically significant differences between the two treatments.[18]As Ivermectin is easily administered (not requiring a rub down of the whole body like lindane or permethrin twice per treatment), compliance is much better.Ivermectin is used in eradication programs of many parasites of both human and animal.Side effects may include mild abdominal pain, nausea, vomiting, myalgia and/or arthralgia, which subside.The product is considered safe for use in children over five months of age.[19]Public health and prevention strategiesThere is no vaccine available for scabies, nor are there any proven causative risk factors.Therefore, most strategies focus on preventing re-infection.All family and close contacts should be treated at the same time, even ifasymptomatic.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: Treatment of furniture and bedding. 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.Itchiness during treatmentOptions to combat itchiness includeantihistaminessuch aschlorpheniramine.Prescription:Hydroxyzine(Atarax).EpidemiologyScabies is impressively egalitarian in its epidemiology: mites are distributed around the world, affecting all ages, races and socioeconomic classes in all different climates.[2]However, it is more often seen in crowded and unhygienic living conditions.[20]Globally, there is an estimated incidence of 300 million cases of scabies a year, 1 million of which occur in the United States.[4]HistoryScabies is an ancient disease.Based on archeological evidence from Egypt and the Middle East, scabies is estimated to date back over 2,500 years.[4]The first recorded reference to scabies is believed to be from theBible(Leviticus, the third book of Moses) ca.1200 BC. Later, the ancient Greek philosopherAristotlereported on lice that would escape from little pimples if they are pricked in the fourth century BC;[21]scholars believe this was actually a reference to scabies.Nevertheless, it was the Roman physicianCelsuswho is credited with designating the term scabies to the disease and describing its characteristic features.[21]The parasitic etiology of scabies was later documented by the Italian physician Giovanni Cosimo Bonomo (1663-1699 AD) in his famous 1687 letter, Observations concerning the fleshworms of the human body.[21]With this (disputed) discovery, scabies became one of the first diseases with a known cause.[4]Animals

Puppy with Scabies (Sarcoptic mange)Many domestic animals have their own species of Sarcoptes mites.Though all can transiently affect humans,[22][23]the mites that cause scabies in animals reproduce on the human body and will multiply within a few days.Humans are especially susceptible to small dogs carrying the mites.Recent outbreaks have started to reach epidemic proportions.[24]The most frequently diagnosed form is sarcopticmangein dogs.In dogs and other animals, scabies produces severe itching and secondary skin infections.Affected animals often lose weight and become unthrifty.Sarcoptes is a genus of skin parasites, and part of the larger family of mites collectively known as scab mites; they are also related to the scab mite Psoroptes, also a mite that infests the skin of domestic animals.Sarcoptic mange affects domestic animals and similar infestations in domestic fowls causes the disease known as scabies leg.The effects of Sarcoptes scabiei are the most well known, causing scabies, or the itch.The adult female mite, having been fertilised, burrows into the skin, usually the hands or wrists, however other parts of the body may also be affected, and lays her eggs.Scabies has been observed on non-domestic animals as well.Gorillas, for instance, are known to be susceptible to infection via contact with items used by humans.[25]Feral AnimalsIn much of the world, domestic animals have gone feral and have no veterinary care and make do with what food they can find.These animals are frequently afflicted with scabies and a host of other ills.[26]See also Crab louse Head louse List of parasites (human) List of cutaneous conditionsReferences1. ^abc"Scabies".DermNet NZ. New Zealand Dermatological Society Incorporated.2. ^abc"DPDx - Scabies".Laboratory Identification of Parasites of Public Health Concern. CDC.3. ^http://www.cdc.gov/scabies4. ^abcdMarkell, Edward K.; John, David C.; Petri, William H. (2006).Markell and Voge's medical parasitology(9th ed.). St. Louis, Mo: Elsevier Saunders.ISBN0-7216-4793-6.5. ^Arlian LG (1989)."Biology, host relations, and epidemiology of Sarcoptes scabiei".Annu. Rev. Entomol.34: 13961.doi:10.1146/annurev.en.34.010189.001035.PMID2494934.6. ^Scheinfeld NS (2004). "Controlling scabies in institutional settings: a review of medications, treatment models, and implementation".Amer J Clin Dermatol5(1): 317.doi:10.2165/00128071-200405010-00005.PMID14979741.7. ^[1]8. ^http://www.nlm.nih.gov/medlineplus/druginfo/uspdi/202170.html9. ^FDA Public Health Advisory: Safety of Topical Lindane Products for the Treatment of Scabies and Lice10. ^abhttp://www.fda.gov/cder/foi/label/2003/006309lotionlbl.pdf.11. ^Commission for Environmental Cooperation. North American Regional Action Plan (NARAP) on lindane and other hexachlorocyclohexane (HCH) isomers. November 30, 2006.12. ^"Lindane Post Marketing Safety Review"(PDF). U.S. Food and Drug Administration (FDA). 2003.13. ^http://www.fda.gov/Drugs/DrugSafety/PublicHealthAdvisories/ucm052201.htm14. ^Lin AN, Reimer RJ, Carter DM (1988). "Sulfur revisited".J Am Acad Dermatol18: 55358.doi:10.1016/S0190-9622(88)70079-1.15. ^Pruksachatkunakorn C, Damrongsak M, Sinthupuan S (2002)."Sulfur for Scabies Outbreaks in Orphanages".Pediatric Dermatology19(5): 44853.doi:10.1046/j.1525-1470.2002.00205.x.PMID12383106. Retrieved 2008-08-01.16. ^Heinrich M,et al.(2005). "Plants as Medicines". in Prance G, Nesbitt M.The Cultural History of Plants. London: Routledge. pp.228.ISBN0415927463.17. ^Walton SF, McKinnon M, Pizzutto S, Dougall A, Williams E, Currie BJ (May 2004). "Acaricidal activity of Melaleuca alternifolia (tea tree) oil: in vitro sensitivity of sarcoptes scabiei var hominis to terpinen-4-ol".Arch Dermatol140(5): 5636.doi:10.1001/archderm.140.5.563.PMID15148100.18. ^Apgar B (January 15, 2000)."Efficacy and Safety of Therapy for Human Scabies Infestation".American Family Physician.Chouela EN, Abeldao AM, Pellerano G,et al.(June 1999)."Equivalent therapeutic efficacy and safety of ivermectin and lindane in the treatment of human scabies".Arch Dermatol135(6): 6515.doi:10.1001/archderm.135.6.651.PMID10376691.Strong M, Johnstone PW (2007). "Interventions for treating scabies".Cochrane Database Syst Rev(3): CD000320.doi:10.1002/14651858.CD000320.pub2.PMID17636630.19. ^Borsboom GJ, Boatin BA, Nagelkerke NJ,et al.(March 2003)."Impact of ivermectin on onchocerciasis transmission: assessing the empirical evidence that repeated ivermectin mass treatments may lead to elimination/eradication in West-Africa".Filaria J2(1): 8.doi:10.1186/1475-2883-2-8.PMID12769825.PMC156613.20. ^Green MS (1989)."Epidemiology of scabies".Epidemiol Rev11: 12650.PMID2509232.21. ^abcRoncalli RA (July 1987)."The history of scabies in veterinary and human medicine from biblical to modern times".Vet. Parasitol.25(2): 1938.doi:10.1016/0304-4017(87)90104-X.PMID3307123.22. ^Chakrabarti A (1985). "Some epidemiological aspects of animal scabies in human population".Int J Zoonoses12(1): 3952.PMID4055268.23. ^Ulmer A, Schanz S, Rcken M, Fierlbeck G (2007). "A papulovesicular rash in a farmer and his wife".Clin Infect Dis45(3): 39596.doi:10.1086/519434.PMID17599314.24. ^[2]25. ^http://www.pbs.org/wgbh/pages/frontline/story/2009/11/doomsday-thinking.html26. ^"Bali Animal Welfare Association". Retrieved 2009-07-28.