Sarcoptes scabiei (Scabies)

Summary

Sarcoptes scabiei is an ectoparasite that causes scabies. The parasite lives on top of the skin and burrows under the skin at flexor surfaces, causing symptoms like pruritic rash and linear burrows. This mite is transmitted mainly by skin-to-skin contact, though it can also be transferred through objects like fabric clothing or bedding. Permethrin in a cream formulation is the first line treatment for scabies.

Key Points

• Sarcoptes scabiei 
  • Characteristics
    • Ectoparasite (mite)
  • Transmission
    • Direct skin-to-skin contact (most common) or via fomites
  • Presentation: Scabies
    • Pruritic rash
      • Type IV hypersensitivity reaction against mites burrowing into skin
      • May be worse at night
      • Involve flexor surfaces/skin folds of wrist, lateral surfaces of fingers, finger webs, genitals, umbilicus, etc.
    • Linear burrows 
  • Diagnosis
    • Skin scrapings with mineral oil prep
      • Mites, ova, feces identified in microscopy
  • Treatment
    • Permethrin cream