Flea Allergy Flashcards by Brittany Jermalovic

Flea allergy

Etiology

Small, brown, wingless bloodsucking insects

Ctenocephalides felis felis = major flea of dogs and cats

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Where do fleas come from?

Fleas outdoors come from eggs deposited from flea infested dogs, cats, and urban wildlife

Eggs deposited can develop into adults (environment)

Pet goes outside and gets fleas
Fleas jump on people and come into house (may not be human specific but can still be on human as a fomite)

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Flea infestation requires

Male and female

Female flea initiates feeding immediately when on host
She then secretes pheromones to attract male
Within 24 hours female begins laying 40-50 eggs/day

Eggs laid on host and fall into environment
Cannot survive in freezing or low humidity

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Flea Eggs

Larvae hatch within 2-10 days

Can go dormant and not hatch for 3-4 months (waiting for perfect conditions

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Eggs and Larvae location

Under furniture
Within carpet/rugs
In crevices/cracks in floorboards

Do not travel far from hatch site

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Larvae: Meal

Feeds on organic debris and flea dirt (poops)

Blood is an essential part of diet

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Larvae to Pupae

Pupate within 8-34 days

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Pupae Cycle

Larva will spin cocoon (sticky and coated with debri)

Inside: larva undergoes metamorphosis

Emerge as adult within 1-2 weeks or remain in cocoon for up to 1 year; takes awhile to fully control an outbreak

Resistant to temperature and desiccation

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Emergence of adult from cocoon

Stimulated by…

Mechanical pressure (walking around)
CO2
Increase temperature

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Emerged adults

Attracted to light
Stimulus fro the jump response is decrease in light intensity (shadow!)

Could bite human before finding its host but it is like ew no this is not right

Must find host within 1-2 weeks or will die

Adults can survive winter on host

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Does C. felis perfer one host or multiple?

Once it has found a host will most likely stay on that host

Possible to jump to another host but rather stay on the original

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C. felis Feeding

Reproductive and feeding machines

Feed in seconds to 5 minutes once on host

Females consume 10x-15x body weight within 24 hours

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Is there a product to stop initial feeding in C. felis?

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Pathophysiology of hypersensitivity reactions

Type?

All dogs and cats develop “sensitization” due to repeated exposure; individual dependent

The more exposure the more likely to develop abnormal response

Type: I and IV (IgE-mediated)

Flea antigen; in saliva

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Pathophysiology of hypersensitivity reactions

Sequela

Hot spots

Self-mutilation

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Pathophysiology

Factors that favor Flea Allergy Dermatitis

Intermittent exposure (drugs waxing and waning)
First exposure to fleas later in life
Animals with environmental allergies (atopy)

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Flea Allergy Dermatitis (KNOW)

Canine Clinical Signs

Pruritus!
Specifically:
Caudal dorsal back
Flanks
Ventral abdomen

Can be generalized

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Flea Allergy Dermatitis (KNOW)

Canine Lesions

Primary papular eruptions
Self-trauma/secondary lesions

Crusting 
Scaling
Alopecia
Lichenification
Hot Spots; acute moist pyotraumatic dermatitis 
Secondary pyoderma (surface pyoderma)

Flea Allergy Dermatitis

Feline Clinical Signs

Pruritus
Specifically:
Neck
Tail base
Not as distinct as canine

Can be generalized

Flea Allergy Dermatitis

Feline Lesions

Crusted papules (miliary dermatitis)

Pruritus with no lesions
Alopecia (excessive grooming)

Eosinophilic granuloma complex:
Indolent ulcers
Eosinophilic plaques
Eosinophilic granulomas

Flea Allergy Dermatitis (KNOW)

Diagnosis

Clinical diagnosis and response to treatment

Clinical signs

Presence of fleas and/or flea feces (dirt) HOWEVER absence does not rule out fleas

Flea Allergy Dermatitis

Secondary infection

Tape worms!

Dipylidium caninum

Flea Allergy Dermatitis

Supplemental diagnostics

Could be supportive…
Allergy testing
Bloodwork; eosinophilia
Skin biopsy; perivascular dermatitis with eosinophils

Flea Allergy Dermatitis

Treatment Goal

Focus on stopping reproduction

Note: owner will HAVE to treat home because there is no way the home is not infested (eggs->larvae->pupae->adults)

Flea Allergy Dermatitis | Treatment approach

Treat secondary infections Treat pruritus Client education Flea treatment

Flea Allergy Dermatitis | Treatment Failure

Poor client compliance Suboptimal treatment regimen (maybe dog swims often so product not as strong) Insecticide resistance? Incorrect diagnosis (different allergy occuring) Should respond within a month of treatment

Flea Allergy Dermatitis | Ineffective treatments

Flea collars over-the-counter Resistance to organophosphates and pyrethroids Flea repellants (Brewer's yeast which will actually make it worse)

Flea Allergy Dermatitis (KNOW) Treatment 2 Approaches

1. Effective residual adulticides; killing fleas within 24 hours before they can begin to lay eggs 2. Use of IGRs (insect growth regulators) or insecticides to kill any eggs that are produced: Methoprene/Pyriproxyfen Lufeneron

Residual Adulticides | Speed of Kill

Initial speed of kill - most products do well Residual speed of kill: Killing newly acquired fleas fast enough to: Prevent flea reproduction Reduce injection of antigen and => minimize FAD Product needs to last!

Residual Adulticides | Isoxazolines; MOA

Inhibits GABA and glutamate gated chloride channels Circulates in plasma proteins Route of elimination: hepatic

Residual Adulticides Bravecto Mechanism (KNOW)

Isoxazoline Drug name: Fluralaner Initial speed of kill: 4 hours: 80.5% 8, 12, 24 hours: 99.4, 100, 100% Residual speed of Kill at 24 hours: 4 weeks: 100% 8 weeks: 100% 12 weeks: 100%

Residual Adulticides | What hour is most important for killing/preventing reproduction

24 hours!

Clinical trial to determine FAD | How does this work

Give medication that lasts a month (Nexgard, Simparica, Credelio) Improve, treatment stops, signs start again than most likely have flea allergy => indefinite treatment

What do Isoxazolines treat?

``` Ectoparasites Flea Tick Demodex mites Scabies Otodectes ```

Residual Adulticides | Capstar

Rx: Nitenpyram ``` Kills fleas in 30 min Speed of kill: 3 hrs: 100% 24 hrs: 100% 48 hrs: 98% ``` Can lose efficacy quickly Must treat every other day for 1 month

Residual Adulticides | Comfortis

Spinosad Speed of kill: 4 hrs: 100% Labeled for 1 month

Residual Adulticides Advantage K9 Advantix

Imidocloprid Permethrin (can kill cats) Moxidectin Topical spot treatment Adheres to skin and hair Labeled for 30 days Bathing may alter effectiveness and longevity

Residual Adulticides | Seresto

Imidocloprid with flumethrin Slow release matrix collar Lasts 8 months but decreases to 5 months if swimming or bathing regularly Fleas, lice, ticks, scabies

Residual Adulticides | Revolution

Salemectin ``` Systemically absorbed Forms reservoirs in sebaceous glands Adulticide and ovicidal More effective in cats! Labeled for 30 days ```

Insect Growth Regulators | What are they?

Can be used on pets or applied to environment Prevent flea eggs from hatching Larvae cannot pupate

Insect Growth Regulators | Examples

Methoprene-Frontline Plus | Pyriproxyfen-Vectra 3D

Insect Development Inhibitors How do these work? Example?

Lufenuron (Sentinel) Chitin synthesis inhibitor (eggs and larvae) Eggs non-viable because larval exoskeleton formation inhibited Products are NOT adulticides

Managing the Itch

MUST treat all secondary infections 2-3 weeks of treatment most likely needed Corticosteroids (anti-inflammatory dose) Apoquel Cytopoint Avoid injections b/c if secondary complications arise you have to ride it out