scabies Flashcards
What is scabies caused by
scabies is caused by the mite Sarcoptes scabiei and is spread by prolonged skin contact. It typically affects children and young adults.
What is the pathophysiology of scabies
The scabies mite burrows into the skin, laying its eggs in the stratum corneum. The intense pruritus associated with scabies is due to a delayed-type IV hypersensitivity reaction to mites/eggs which occurs about 30 days after the initial infection.
What are the features
widespread pruritus
linear burrows on the side of fingers, interdigital webs and flexor aspects of the wrist
What is seen in children
in infants, the face and scalp may also be affected
What are the secondary features
secondary features are seen due to scratching: excoriation, infection
What is the management
permethrin 5% is first-line
malathion 0.5% is second-line
give appropriate guidance on use (see below)
pruritus persists for up to 4-6 weeks post eradication
What advice to give to patients
avoid close physical contact with others until treatment is complete
all household and close physical contacts should be treated at the same time, even if asymptomatic
launder, iron or tumble dry clothing, bedding, towels, etc., on the first day of treatment to kill off mites.
How to apply insecticide cream
apply the insecticide to all areas, including the face and scalp
apply the insecticide cream or liquid to cool, dry skin
pay close attention to areas between fingers and toes, under nails, armpit area, creases of the skin such as at the wrist and elbow
How long to leave on
allow to dry and leave on the skin for 8-12 hours for permethrin, or for 24 hours for malathion, before washing off
reapply if insecticide is removed during the treatment period, e.g. If wash hands, change nappy, etc
repeat treatment 7 days later
What is Norwegian scabies
Crusted scabies is seen in patients with suppressed immunity, especially HIV.
What is within the crusted skin
hundreds of thousands of organism
