Flea Allergy

Question 1

What is the most common flea on dogs and cats?

Answer 1

Ctenocephalides felis

Question 2

What diseases can be transmitted by Ctenocephalides felis?

Answer 2

• can harbor plague
• murine typhus and tularemia
• dipylidium caninum
• cat scratch fever

Question 3

Describe the life cycle of Ctenocephalides felis

Answer 3

• 21 d under ideal circumstances
• Eggs are laid after a blood meal –> fall off the host in the environment (resistant to insecticides except IgR)
• Larva are present in the environment, covered w/ small hairs, molt 2x, attracted by dark warm areas, eat small organic debris and blood-filled flea feces (vacuum to remove food)
• Cocoon or pupa: most resistant stage, can be dormant for many months
  
  • hatch d/t mechanical pressure/vibration, body temp, low concen. of CO2
• New adult finds a host pet on which to feed

Question 4

What are the predisposing factors for flea allergies?

Answer 4

• lack of exposure neonatally or at young age
• intermittent exposure
• small amounts
• atopy (e.g. environmental allergy)

Question 5

What type of hypersensitivity reaction is a flea allergy?

Answer 5

• mixed
  
  • Type I hypersensitivity (IgE mediated)
  • Delayed (cell mediated)
  • Cutaneous basophil hypersensitivity

Question 6

What are the clinical signs of flea allergy dermatitis?

Answer 6

• no breed or sex predisposition
• age of onset = 1-5 yrs (as early as 2 mo)
• primary lesion = papule
• self-trauma and absence of fleas
• lesions in back half of dog
  
  • lower back, perineum, tailhead, hind legs and umbilical region
• secondary Staph infection common
• seasonal in most areas

Question 7

Describe feline flea allergy dermatitis?

Answer 7

• miliary dermatitis
• feline symmetrical alopecia
• eosionophilic granuloma complex

Question 8

How do you diagnose FAD?

Answer 8

• clinical signs and R/O’s
• presence of fleas or feces
• carrier animals
• tapeworm hx
• IDST - positive helpful, negative - still may be FAD
  
  • whole flea antigen
• histopath - nonspecific, superficial perivascular dermatitis w/ eosinophils
• positive response to elimination of fleas
• intradermal allergy testing or blood testing

Question 9

How do you treat flea allergy dermatitis?

Answer 9

• varies with pet(s) and environment
• environment must be considered in FL
• chemical adulticides used on pets
• repellents in allergic dogs
• IGR’s
• kill the fleas!
• tx the pyoderma
• antipruritic tx
• steroids? antihistamines?
• no immunotherapy