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Scabies is an parasitic infestation of the skin by the human mite Sarcoptes scabiei.
The female mite burrows into the superficial layer of the skin forming a slightly narrow tunnel.  Burrows ae most commonly found in the web spaces between the fingers, on the wrists & elbows, & on the ankles & feet.   It is transmitted via direct contact and causes itchy papules mostly on the wrists, axillae, areolae, lower abdomen, genitals and buttocks. The hall mark visual diagnostic sign is the burrow, a thread like scaly line in the skin, typically seen at the wrists or web spaces of the hands. This is the superficial "tunnel" the mite creates in the skin, look carefully for this sign, it is diagnostic of scabies when accurately recognized.

The lesions may be red or appear as white, gray, or black thread-like lines.  The lesions can be intensely pruritic, especialy at night.  Occasionally 2-5 mm nodules appear or vesicles develop, esp. in children.  The lesions can get secondarily infected with Streptococcus pyogenes or Staphylococcus aureus.

Definitive diagnosis of scabies is made by recovering the mite from a burrow by skin scraping & looking at the skin scraping under a microscope. Sensitivity of this method is low in typical scabies but very high in crusted scabies.

Topical scabicides as Elimite (Permethrin) 5 % cream for 8-12 hours.  
Topical Lindane is no longer available for sale in California.
Oral Ivermectin is also effective for crusted scabies, although not approved for this purpose by the FDA.
Oral antihistamines & topical steroids may be used for the itching.
* Family members must be treated at he same time, & a good environmental cleaning of the home is essential.

Reporting of single cases of atypical or crusted scabies & outbreaks of scabies are mandated & should be reported immediately by telephone to the Communicable Disease Reporting System Hotline at (888) 397-3993