Scabies : Diagnosis and Treatment

Scabies : Diagnosis and Treatment

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1. What is scabies?

an itchy skin disease caused by mite (known as sarcoptes scabiei var hominis)
causing intense itch, especially at night
very contagious
can form nodules (nodular scabies)
crusted scabies

aka Norwegian scabies
more common in immunocompromised
diffuse hyperkeratosis

2. How to diagnose scabies?

clinically diagnosed
history of similar symptoms among family members
presence of erythematous papulo-vesicular lesions at axillary, nipple periumbilical, elbows, interdigits, beltline and genital area
can also diagnosed via microscopy - identification of mites / eggs / feces of scabies

3. How to treat scabies?

Medications

scabicides (one of the followings)

permethrin 5%

first line
apply for 8-12 h
repeat 1 week later
safe for pregnant / breastfeeding
not for <2 months old

benzyl benzoate

second line
strength

2-12 years old : 12.5%
>12 years old : 25%

apply for 24h
for 3 consecutive days
not for pregnant / breasfeeding
not for <2 months old

precipitated sulphur 6-10%

apply for 24 hours
for 3 consecutive days
safe for infant and breastfeeding

lindane 1%

apply for 6-8 hours
not for pregnant, breastfeeding
not for <10 years old
side effect : neurotoxic

crotamiton 10%

for classical scabies : apply 24 hours for 7 days
for nodular scabies : apply to nodules TDS for 5-14 days

malathion 5%

apply overnight

ivermectin

if failed 1st and 2nd line treatments
used with topical scabicide in crusted scabies
200mcg/kg, single dose, repeat after 2 weeks
not for < 5 years old or <15kg
not for pregnant / breastfeeding

antibiotics for 7 days

if presence of secondary infection

antiseptic soak

KMNO4 1:10,000
for impetiginized scabies

anti-pruritic
steroid cream

for nodular scabies
use moderate to potent strength
use for 2 weeks

Must treat all family members and close contacts as well
Wash bedding, clothes, personal items at high temperature (>50C)

or can keep in plastic bag for 72 hours (mites cannot survive without host longer than that)

vacuum mattress / carpets

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