Scabies

Question 1

What causes scabies?

Answer 1

Sarcoptes scabiei mite
spread by prolonged skin contact

Question 1

Describe how scabies causes pruritis

Answer 1

Delayed-type IV hypersensitivity reaction to mites/ eggs which occurs ~30 days after the initial infection.

Question 2

Describe the symptoms of scabies

Answer 2

Intense generalized itch (worse at night)

Question 3

Describe the rash seen in scabies

Answer 3

Linear burrows on the side of fingers, interdigital webs + flexor aspects of wrist
Secondary features due to scratching: excoriation, infection

Question 4

Which patients may develop crusted scabies?

Answer 4

Immunocompromised

Question 5

Describe diagnosis of scabies

Answer 5

Clinical
Definitive dx with ink burrow test/ microscopy of skin scrapings

Question 6

Describe management of scabies

Answer 6

Permethrin 5%: apply to whole body + leave on for 8-12h
(2nd: Malathion 0.5%: leave on for 24h)
Repeat 7 days later

Question 7

What advice should be given during management of scabies?

Answer 7

Avoid close physical contact with others until Tx complete
Launder clothes, bedding, towels at 60 degrees on 1st day of Tx

Question 8

For how long does pruritus persist post eradication of scabies?

Answer 8

4-6w

Question 9

What is Norwegian (crusted) scabies?

Answer 9

hyperinfestation with 1000s or millions of mites present in exfoliating scales of skin

Question 10

Describe S/S of crusted scabies

Answer 10

Pruritus mild or absent due to impaired immune response.
Skin lesions consist of generalized, poorly defined, erythematous, fissured plaques covered by scales + crusts.

Question 11

What is used in treatment of crusted scabies?

Answer 11

Ivermectin (+ isolation)