Scabies

Question 1

Define scabies.

Answer 1

Scabies is caused by infestation with the ectoparasite Sarcoptes scabiei, a mite that burrows through the human stratum corneum. Spread is primarily via direct contact with an individual with scabies.

Question 2

What is the aetiology of scabies?

Answer 2

Scabies is caused by infection with the ectoparasite Sarcoptes scabiei, variety hominis. This 0.3- to 0.5-mm mite burrows into the epidermis and tunnels through the stratum corneum, laying 2 to 4 eggs per day.

Question 3

What are risk factors for scabies?

Answer 3

Overcrowded living conditions/poverty

Living in close quarters with others who are infected

Age under 15 or over 65 years

Sexual contact with new or multiple partners

Immunosuppression

Question 4

Summarise the epidemiology of scabies.

Answer 4

Scabies is endemic in certain populations but may be seen episodically or in epidemics in other populations. The prevalence of scabies is estimated to be 300 million cases worldwide. However, this varies geographically and in some communities, particularly those that are sub-tropical and developing, prevalence may approach 50%.

Question 5

What are the signs and symptoms of scabies?

Answer 5

Generalised and intense pruritus, typically worse at night

Burrows

Papules, vesicles, excoriations

Positive ink burrow test

Question 6

What investigations should be performed for scabies?

Answer 6

Ectoparasite preparation

Question 7

What is the management for scabies?

Answer 7

Permethrin or ivermectin

Sulfur 6% in petroleum for infants under 2 months

Question 8

What are complications associated with scabies?

Answer 8

Post-scabetic pruritus

Secondary infection

Nodular scabies or pseudolymphoma

Question 9

What is the prognosis of scabies?

Answer 9

Most people with scabies are cured after 2 treatments with ivermectin or permethrin, the 2 first-line treatments.