SPOTTERS
MEDICINE
SCABIES
🔹 Definition:
Scabies is a
contagious parasitic skin infestation caused by the Sarcoptes scabiei
mite, leading to intense itching and a papular rash.
🔹 Etiology / Causative Agent:
- Sarcoptes scabiei var. hominis (human itch mite)
- Transmitted by prolonged
skin-to-skin contact, especially in crowded conditions
🔹 Pathogenesis:
1.
Female
mite burrows into stratum corneum and lays eggs
2.
Mite
antigens induce type IV hypersensitivity
3.
Itching due to
immune response, not mite bite
🔹 Clinical Features:
- Intense pruritus, especially at night
- Burrows: thin, greyish, wavy lines on
skin
- Common sites:
- Finger webs
- Wrists
- Axillae
- Waistline
- Genitalia
- Nodular lesions in infants and
immunocompromised
🔹 Types of Scabies:
1.
Classic Scabies
– most common
2.
Crusted Scabies (Norwegian) – in immunocompromised patients
3.
Nodular Scabies
4.
Scabies incognito – modified by steroid use
🔹 Diagnosis:
- Clinical features + history
- Ink test / Dermoscopy – to visualize burrows
- Skin scraping under microscope to see mites,
eggs, or feces
🔹 Treatment:
Topical:
- Permethrin 5% cream – drug of choice
- Benzyl benzoate, sulfur ointment
(alternative)
- Apply to whole body (neck down),
repeat after 1 week
Oral:
- Ivermectin 200 mcg/kg in resistant or
crusted scabies
🔹 Prevention:
- Treat all close contacts
simultaneously
- Wash clothes, bedding in hot
water
- Avoid close contact until
treatment is completed
🔹 Complications:
- Secondary bacterial infection
(impetigo)
- Post-scabetic eczema
- Crusted scabies in
immunocompromised
🔹 Prognosis:
- Good with treatment, but
reinfestation is common if contacts are not treated
DR.C.GANESAN
M.D.,
PROFESSOR OF
MEDICINE
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