10. z
About scabies
ď§ Worldwide distribution
ď§ In all socio-economic classes
ď§ Contagious ectoparasitic infestation
ď§ Affects only man
ď§ Obligate human parasite
11. z
Zoonotic scabies
ď§ Seen in dogs, cats, horses etc
ď§ Rarely transmitted to humans
ď§ Can be differentiated from human scabies by
ď§ - distribution of the rash
ď§ - absence of borrows in hand
12. z
Life cycle stages of the mite
ď§ Eggs
ď§ Larvae
ď§ Nymph
ď§ Adult (M&F)
13. z
Life cycle
ď§ Female mite mates with female mite in the burrow.
ď§ Female mite lays eggs and faeces in the burrows
ď§ Eggs hatch
ď§ Larvae are released
ď§ They come out of the burrow, on to the skin surface
ď§ Then forms new moulting pouches upto straitum corneum
ď§ Larvae moults Into nymph
ď§ The live in molting pouches and become adults
ď§ Female remains in the burrow, while the male go out
16. z
Skin Burrows
ď§ Visible torturous sepentine like lines over the skin
ď§ The mite digs into the superfial skin and reside there
ď§ Never go beyond striatum corneum
ď§ Mainly at night
17. z
Pathogenesis
ď§ Adult mite, eggs, faeces in skin burrows trigger host
immune system.
ď§ Local itching, scratching, vesicles become
pustules, generalised itching, hypersensitivity
ď§ Larvae on skin can be transmitted to another
person by direct or indirect contact
18. z
Preferred body sites
Areas that are thin and
wrinkled
ď§ Finger webs
ď§ Wrist
ď§ Elbow, knee
ď§ Axilla, scrotum
ď§ Breast , nipple
ď§ Buttocks
ď§ Feet
ď§ Around umbilicus
21. z
Other types of scabies
ď§ Neonatal scabies
ď§ Crusted scabies in the immunocompromised
22. z
Crusted scabies
ď§ Seen in the immunocompromised
ď§ Also called Norwegian scabies
ď§ No burrows
ď§ Profuse crushing, hyperkeratotic plaques
ď§ Severe from of scabies
ď§ A large number of mites present on skin surface
23. z
Neonatal scabies
ď§ Over the first year
ď§ Buttocks, perineum common
ď§ Burrows impossible to find
ď§ 2ry pustules, pyoderma