Parasitic Infections: SCABIES

Question 1

SCABIES Clinical Feature

Answer 1

characterized by superficial burrows, intense pruritus (especially nocturnal), and secondary infection
•

Question 2

SCABIES primary lesion

Answer 2

superficial linear burrows; inflammatory papules and nodules in the axilla and groin

Question 3

SCABIES secondary lesion:

Answer 3

small urticarial crusted papules, eczematous plaques, excoriations

Question 4

SCABIES common sites:

Answer 4

axillae, groin, buttocks, hands/feet (especially web spaces), sparing of head and neck
(except in infants)

Question 5

SCABIES Pathophysiology. Resservory, incubation, and then?

Answer 5

• scabies mite remains alive 2-3 d on clothing/sheets
• incubation of 1 mo, then pruritus begins
• re-infection followed by hypersensitivity in 24 h

Question 6

SCABIES Etiology

Answer 6

Sarcoptes scabiei (a mite)

Question 7

SCABIES risk factors:

Answer 7

sexual promiscuity, crowding, poverty, nosocomial, immunocompromised

Question 8

SCABIES Differential Diagnosis

Answer 8

asteatotic eczema, dermatitis herpetiformis, lichen simplex chronicus (neurodermatitis)

Question 9

SCABIES Investigations

Answer 9

microscopic examination of root and content of burrow and mineral oil mount for mite, eggs, feces
• skin biopsy may sometimes show scabies mite

Question 10

SCABIES Management Topical

Answer 10

bathe, then apply permethrin 5% cream (i.e. Nix®) from neck down to soles of feet (must be left on for
8-14 h and requires second treatment 7 d after first treatment)
• mid potency topical steroids and antihistamines for symptom management

Question 11

SCABIES Management Measures

Answer 11

• treat family and close contacts

* change underwear and linens; wash twice with detergent in hot water cycle then machine dry

Question 12

SCABIES considerations

Answer 12

• pruritus may persist for 2-3 wk aFter effective treatment due to prolonged hypersensitivity reaction