Scabies

Question 1

What is scabies?

Answer 1

A parasitic infection caused by the human scabies mite, Sarcoptes scabiei

Question 2

What is the pathophysiology of scabies infection?

Answer 2

Protein and faeces produced by the mites causes a type 4 hypersensitivity reaction

Question 3

What are the risk factors for scabies?

Answer 3

Developing countries
Crowded conditions
Adolescence
Female sex
Winter months

Question 4

What are the clinical features of scabies?

Answer 4

Intense pruritis, particularly at night
Linear burrows on the side of fingers, interdigital webs and flexor aspects of the wrists
Excoriation
Symmetrical erythematous papules

Question 5

What investigations can be used to diagnose scabies?

Answer 5

Ink burrow test
- black or blue ink is applied to the papules and wiped away - the ink will track down the mite burrow
Skin scrapings

Question 6

What is the first-line management of scabies?

Answer 6

Permethrin 5% cream
- All contacts and household members should receive treatment
Topical crotamiton cream (anti-itching agent)

Question 7

What is the second-line treatment of scabies?

Answer 7

Malathion aqueous 0.5%

Question 8

What is crusted scabies?

Answer 8

Also known as Norweigan scabies
- Serious infestation with scabies in patients that are immunocompromised
- They present with scaly plaques like psoriasis

Question 9

What is the management of crusted scabies?

Answer 9

Oral ivermectin and isolation

Question 10

What advice should be given to patients diagnosed with scabies?

Answer 10

Avoid having sex or physical contact until treatment is completed
Avoid sharing bedding or clothing
Bedding, clothing and towels should be washed at a high temperature
Patients should hoover carpets and wash furniture