Scabies

• Caused by Sarcoptes scabiei
• Highly contagious
• Mainly in pigs, dogs, also horses, cattle, sheep, goats and cats
• Intense pruritus due hypersensitivity to mites borrowing through stratum corneum
• Usually starts with external pinnae -> head -> neck -> generalised
• Grossly:
  • Erythematous macules, papules, crusts
  • If chronic -> lichenified, hairless
• Microscopically:
  • Hyperplastic, spongiotic, superficial perivascular dermatitis
  • Crusting, eosinophil infiltration
  • Mites are not commonly seen, but eggs and feces may be found in stratumn corneum