Scabies Disease

DESCRIPTION
A contagious disease caused by infestation of the skin by the mite Sarcoptes scabiei, var. hominis
  • System(s) affected: Skin/Exocrine
  • Genetics: N/A
  • Incidence/Prevalence in USA: Common, although number of cases per year is declining as the epidemic, which began in 1971, passed its peak (1986). Worldwide incidence is 300 million cases per year.
  • Predominant age: Children and young adults
  • Predominant sex: Male = Female
SIGNS AND SYMPTOMS
  • Generalized itching (often severe)
  • Nocturnal pruritus
  • Burrows in finger webs, wrists, hands, feet, penis, scrotum, buttocks, waistline
  • Vesicles and papules (discrete)
  • Secondary erosions or excoriations
  • Pustules (if secondarily infected)
  • Scaling
  • Erythema
  • Nodules in covered areas (buttocks, groin, axillae)
  • Atypical infestations in immunosuppressed patients
CAUSES
Sarcoptes scabiei, var. hominis
RISK FACTORS
  • Personal skin-to-skin contact, e.g., sexual promiscuity, crowding, poverty, nosocomial infection
  • Immunocompromised patients, including HIV/AIDS
  • Atopic eczema
LABORATORY

N/A

Drugs that may alter lab results: N/A
Disorders that may alter lab results: N/A

PATHOLOGICAL FINDINGS
Skin biopsy of a nodule (although rarely performed) will reveal portions of the mite in the corneal layer
SPECIAL TESTS
N/A
IMAGING
N/A
DIAGNOSTIC PROCEDURES
  • Examination of skin with magnifying lens - look for typical burrows in finger webs, on flexor aspects of the wrists, and penis. Look for a dark point at the end of the burrow (the mite). The mite can be extracted with a 25-gauge needle and examined microscopically.
  • Mineral oil mounts - place a drop of mineral oil over a suspected lesion. Non-excoriated papules or vesicles may also be sampled. Scrape the lesion with a #15 surgical blade. Examine under a microscope for mites, eggs, egg casings, or feces. Scraping from under fingernails may often be positive.
  • Potassium hydroxide (KOH) wet mount - transfer skin scrapings directly to a glass slide, add a drop of KOH, and apply a cover slip. Examine the slide for diagnostic material. If none is evident, heat slide gently to separate squamous cells and reexamine.
  • Burrow ink test - if burrows are not obvious, apply blue-black ink to an area of rash. Wash off the ink with alcohol. A burrow should remain stained and become more evident. Then apply mineral oil, scrape, and observe microscopically as previously noted.
APPROPRIATE HEALTH CARE

Outpatient

GENERAL MEASURES
  • Treat all intimate contacts and close household and family members.
  • Wash all clothing, bed linen, and towels in a normal wash cycle.
SURGICAL MEASURES

N/A

ACTIVITY

Full activity

DIET

No special diet

PATIENT EDUCATION
  • Patient instruction sheet "Scabies" in Epstein: Common Skin Disorders (see References)
  • Griffiths: Instructions for Patients, Philadelphia, W.B. Saunders Co.
  • Schmitt: Instructions for Pediatric Patients, Philadelphia, W.B. Saunders Co.
PREVENTION/AVOIDANCE

N/A

POSSIBLE COMPLICATIONS
  • Eczema
  • Pyoderma
  • Postscabetic pruritus
  • Nodular scabies
EXPECTED COURSE AND PROGNOSIS
  • Lesions begin to regress within 1 to 2 days, along with the worst itching.
  • Some itching and dermatitis commonly persist for 10 to 14 days and can be treated with antihistamines and/or topical or oral corticosteroids.
  • Nodular lesions may persist for several weeks, possibly requiring intralesional or systemic steroids.
  • Some cases of lindane-resistant scabies have been reported; these respond to permethrin treatment.
ASSOCIATED CONDITIONS

N/A

AGE-RELATED FACTORS

Pediatric: Infants often have more widespread involvement. They are occasionally infested on the face and scalp (rare for adults). Vesicular lesions on the palms and soles are also more commonly seen. When treating infants with permethrin, the entire body should be treated.
Geriatric: The elderly often itch more severely, despite fewer cutaneous lesions. Elderly at risk for extensive infestations, perhaps related to a decline in cell-mediated immunity. May see back involvement in those who are bedridden.
Others: N/A

PREGNANCY

Permethrin and lindane are category B drugs. Until more information is available precipitated ´sulfur´ appears to be the safest treatment in pregnant or lactating women.

OTHER NOTES

N/A

ABBREVIATIONS

N/A

Clinical Investigations

ROLE OF HOMOEOPATHY

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