Cheyletiella

Background

• Genus of mite

Epidemiology

• Live on dogs, cats, and rabbits, but can incidentally infect humans
  • On animals, usually on the backs and can cause dandruff-like scales ("walking dermatitis", "walking dandruff", or dorsal seborrhea sicca)
• Human are an incidental host
• Life cycle completed within 21 days on one host
• Adult females can survive off of hose for up to 10 days
• Eggs can be shed with animal's hair, creating an environmental reservoir for reinfestation

Clinical Manifestations

• Can be asymptomatic
  • Source animal may be asymptomatic
• Causes cheyletiellosis, or Cheylatiella dermatitis
• Multiple erythematous pruritic papules on arms, trunk, and buttocks
  • May have area of central necrosis
  • May develop papulovesicles, urticarial weals, vesicobullous eruptions, or excoriated erosions
  • Distribution is essentially the areas of the body that most commonly contact the pet
• Presents similar to scabies, but recurs despite treatment

Diagnosis

• Diagnosis made based on diagnosis of pet (dorsal seborrhea sicca) using skin scrapings or acetate tape impressions that demonstrated mites or eggs
• Mites are not usually seen on human hosts (they "bite and run" back to their animal host)

Management

• Mainstay of treatment is to treat the pet, since the human is an incidental host
  • Treatments include mite-icidal shampoos, such as ivermectin, phoxim, and moxidectin
  • May need multiple treatments
• Lesions in pet owner typically resolve within 3 weeks