Flea Allergy (Marsella)

Question 1

Flea allergy dermatitis (frequency)

Answer 1

Most common external parasite. FAD most common skin disease. Most common reason to see vet (outside of vax)

Question 2

Fleas in dogs & cats

Answer 2

Ctenocephalides felis most common. Pulex irritans (human flea). Echidnophagia gallinacea (avian stick tight flea).

Question 3

Ctenocephalides felis can transmit…

Answer 3

• Plague
• Murine typhus
• Tularemia
• Diplydium caninum
• Cat scratch fever

Question 4

Ctenocephalides felis life cycle length

Answer 4

Life cycle 21 days under ideal circumstances (i.e. FL weather)

• Does not survive in high altitude or low humidity
• Adult spends entire life on host

Question 5

Flea eggs

Answer 5

• Laid after bloodmeal
• Fall off hose in the environment (carpets)
• Resistant to all insecticides except IgR

Question 6

Flea larva

Answer 6

• Persist in environment
• Molt twice
• Move away from light & hot temp
• Eat small organic debris and blood filled flea feces

Question 7

Getting rid of larva

Answer 7

Vacuuming helps remove larval food from environment.

• little hairs on larvae help them cling to carpet, so hard to directly take out

Question 8

Flea cocoon/pupa

Answer 8

• Most resistant stage (freezing, desiccation, insecticides useless, difficult to vacuum up)
• Can be dormant for months

Question 9

Emergence of young fleas from pupa

Answer 9

Mechanical pressure/vibration, body temperature, low concentrations of CO₂​ causes young adults to seek a host animal for blood meal.

Question 10

Predisposing factors to flea allergy

Answer 10

• Lack of exposure neonatally or at young age
• Intermittent exposure
• Small amounts
• Atopy (tendency to be allergic)

Question 11

Flea allergy hypersensitivity

Answer 11

Mixed hypersensitivity

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

Question 12

Clinical signs of FAD

Answer 12

• Papules
• Pruritis
• Self-trauma
• Absence of fleas (or just a few)
• Worsen w/ subsequent years
• Age of onset 1-5yrs
• Lesions on back 1/2 of dog (lower back, perineum, hind legs, umbilical area)
• Secondary Staph infections common
• Seasonal w/ waxing & waning of signs

Question 13

Feline FAD manifestation types

Answer 13

1. Miliary dermatitis
2. Feline symmetrical alopecia
3. Eosinophilic granuloma complex

Question 14

FAD diagnosis

Answer 14

• Positive response to elimination of fleas
• Clinical signs and rule out other causes
• Precense of fleas or feces (lack of fleas does NOT rule out)
• Carrier animals
• Tapeworm history
• Intradermal skin test (postive confrims, negative does NOT rule out)
• Histopathology

Question 15

FAD histopathology

Answer 15

• Non-specific
• Superficial perivascular dermatitis w/ eosinophils

Question 16

FAD therapy

Answer 16

• Chemical adulticides used on pets (all year long)
• Repellents in allergic dogs
• IGR (Flea spray)
• Steroids and antihistamines may help