Scabies

Question 1

What causes scabies?

1 - head louse
2 - mite Sarcoptes scabiei
3 - trichophyton
4 - all of the above

Answer 1

2 - mite Sarcoptes scabiei

Only affects humans

Question 2

What is the incidence of scabies?

1 - 20 : 100,000
2 - 200 : 100,000
3 - 2000 : 100,000
4 - 20,000 : 100,000

Answer 2

2 - 200 : 100,000

• very contagious and can be spread in schools, care homes, work places etc…

Question 3

Which age group does the incidence of scabies peak in?

1 - 1-5
2 - 5-10
3 - 6-15
4 - 16-21

Answer 3

3 - 6-15

Question 4

Scabies mite burrows into the skin, and lay their eggs in which layer of the skin?

1 - stratum basale
2 - stratum spinosum
3 - stratum granulosum
4 - stratum lucidum
5 - stratum corneum

Answer 4

5 - stratum corneum

Question 5

The intense pruritus associated with scabies is due to a delayed-type IV hypersensitivity reaction to mites/eggs in the skin. Typically how long does it take for this to occur following the initial infection?

1 - 3 days
2 - 7 days
3 - 14 days
4 - 30 days

Answer 5

4 - 30 days

Question 6

Which of the following is NOT a clinical feature of scabies?

1 - widespread pruritus
2 - linear burrows on the side of fingers, interdigital webs and flexor aspects of the wrist
3 - face and scalp may also be affected
4 - erythematous plaques

Answer 6

4 - erythematous plaques
- worse in immunocompromised patients

Secondary features include:
- scratching: excoriation, infection

Question 7

Typically, where does scabies present most commonly?

1 - web space in-between fingers and wrists
2 - buttocks
3 - soles
4 - waist
5 - axillae

Answer 7

1 - web space in-between fingers and wrists

Question 8

Which of the following is the 1st line treatment for scabies?

1 - permethrin 5%
2 - anti-fungals
3 - malathion 0.5%
4 - skin bleaching

Answer 8

1 - permethrin 5%
1st line

3 - malathion 0.5%
2nd line

Despite treatment pruritus may persists for up to 4-6 weeks post eradication

Question 9

Permethrin 5% is the 1st line treatment for scabies. How often should patients apply this?

1 - twice daily
2 - every day
3 - twice a week
4 - every 7 days for 2 weeks

Answer 9

4 - every 7 days for 2 weeks

• apply to whole body from jaw down
• apply to cool, dry skin
• allow to dry and leave on the skin for 8-12 hours for permethrin, or for 24 hours for malathion, before washing off
• repeat treatment 7 days later

Question 10

Patients with a confirmed diagnosis of scabies should be advised which of the following?

1 - avoid close physical contact with others until treatment is complete
2 - provide treatment to those who have been in contact
3 - clean the house and all items come into contact with to kill mites
4 - all of the above

Answer 10

4 - all of the above

Need to trace sexual contact back up to 8 weeks