Protozoal Dermatosis

• Cutaneous infection may become a part of systemic infection
• Mostly caused by Leishmania
• Transmitted by sandflies
• Occurs in dogs, cats and rodents (also humans)
• Grossly in dog:
  • Generalised alopecia
  • Silvery white scales
  • Nodules and ulcers if more severe
  • Mainly on muzzle, ears and eyes where flies feed
• Microscopically:
  • Hyperkeratosis, parakeratosis, crusts
  • Granulomatous nodules in dermis
  • Macrophages, some lymphocytes and plasma cells - periadnexal pattern, may affect sebaceous glands
  • Organisms may be found extra or intracellularly