Scabies Flashcards
Cause of Scabies
Sarcoptes scabiei (Itch mite)
Physical features of Sarcoptes scabiei
Oval, ventrally flattened mite with dorsal spines
Innoculation of scabies mite
Fertilized female burrows into Stratum Corneum and deposits eggs
Classic lesions of Scabies
Pruritic Papular lesions, Escoriations and Burrows
Site predilection of Scabies
- Finger webs
- Wrists
- Axillae
- Areolae
- Umbilicus
- Lower Abdomen
- Genitals
- Buttocks
Imaginary circle intersecting main sites of Scabies Involvement
Circle of Hebra
Sites along Circle of Hebra
- Axillae
- Elbow flexures
- Wrists and Hands
- Crotch
Distribution of scabies in adults vs infants
Adults: Scalp and Face
Infants: Entire cutaneous surface
Characteristics of scabies burrows
Slightly elevated, grayish, tortous lines on the skin
Vesicle/Pustule containing the mite at end of the burrow
How to identify scabies burrows?
- Drop of India ink or Gentian violet on the area
then removed with alcohol.
= Thin, threadlike burrows retain the ink
- Drop Mineral oil on lesion then scrape using blade or needle. Check under microscope
Differential diagnosis of Scabies
- Bullous pemphigoid
- Langerhans cell histiocytosis
Variant of scabies with:
- Dull red nodules 3-5mm
- Active scabies
- May or may not itch
- Scrotum, Penis or Vulvar areas
Nodular scabies
A variant of scabies in
Immunocompromised and Debilitated individuals
Crusted Scabies
or
Norwegian Scabies
or
Hyperkeratotic Scabies
Characteristics of Crusted Scabies
- Crusts teem with mites
- Facial involvement
- Slight pruritus
- Swollen and crusted fingertips
- Distorted nails
- Severe fissuring on genitalia and buttocks
- Heavy keratosis on pressure-bearing areas
Transmission of Scabies
- Close personal contact
- Contaminated linens and clothing
When does sensitization begin in Scabies?
2-4 weeks after the onset of infection
Hallmark symptom of scabies
Nocturnal pruritus
Most effective medication for Scabies
Permethrin 5% cream
sig. Thoroughly rub into skin from NECK to FEET
with particulat attention to creases, perianal areas, umbilicus and free nail edge and folds.
Wash off 8-10 hours later. Change linens and clothing.
