Scabies

Question 1

Definition

Answer 1

Intensely itchy skin infestation caused by a parasite.

Question 2

What is the causative organism

Answer 2

Sarcoptes Scabiei

Question 3

Pathophysiology of scabies infection

Answer 3

It burrows into the epidermis and tunnels through the stratum corneum

Question 4

Risk factors

Answer 4

• close contact with an infected person
• crowded living situations
• Winter time

Question 5

What are the types of scabies - 2

Answer 5

Classical - infestation with low number of mites (5-15)

Crusted scabies - infesation with thousands or millions, develops as a result of insufficient immune response

Question 6

Presentation of typical scabies

Answer 6

• intense generalised itching, usually worse at night
• erythematous papules, distributed around umbillicus, waist, genitalia, breast, buttocks. Head and back are spared

-may have nodular lesions

-may have a ‘burrow’, thin brown/grey line where mite is burrowing

Question 7

Presentation of crusted scabies (Norweigian scabies)

Answer 7

-milder itching
- skin lesions are generalized erythematous plaques, which may have yellow/brown aspects

Question 8

Investigations

Answer 8

• clinical judgement mainly used
• ‘Ink burrow test’, dark ink is applied to papule and wiped off. a positive test shows dark zigzagged line running across and away from lesions due to ink tracking from mite

Question 9

Differentials

Answer 9

insect bites
pubic/body lice
atopic eczema

Question 10

Management

Answer 10

CHILD UNDER 2
-permethrin 5% cream

CLASSICAL SCABIES OVER 2
- permethrin 5% cream
- infomation on scabies and how to treat

NORWEIGAN SCABIES
- high potency topical steroids, oral steroids, intralesional steroids