Approach to pruritus, feline reaction patterns Flashcards
What is the clinical presentation pruritus in dogs and cats?
- Scratching, chewing
- Licking feet (dogs)
- Feather-plucking (birds)
*Overgrooming (=‘self-induced alopecia’) (cats)- Also –> tufts of hair in house, vomiting furballs, hair in faeces
- One of the four feline reaction patterns
What are the four cutaneous reaction patterns in cats?
- Self-induced alopecia (SIA)
- Face, head and neck pruritus (FHN)
- Miliary dermatitis (MD)
- Eosinophilic granuloma complex (EGC)
often more than one pattern present
What are the key features of Self-induced alopecia (SIA) in cats?
what is a DD for this?
Bilaterally symmetrical alopecia in areas that cat can reach with tongue
- Hair often stubbly
- Damaged distal tips on trichograms
- Often not recognised by owner
- +/- tufts of hair in house, vomiting furballs, hair in faeces
d/d spontaneous loss – may also be symmetrical
* Much less common
* Hair often easily epilated
What are the key aspects of Face, Head and neck pruritus?
extreme self trauma to the head, cat will scrate until ulcerated
1/3 of cases are caused by flea allergic disease
What are the key features of miliary dermatis in cats?
Papulocrustous lesions (feels lumpy), especially on dorsum
- most common cause is flea allergy
What are the key features of eosinophilic granuloma complex in cats?
A. Eosinophilig granuloma
- Well-demarcated, solid, raised, yellow to pink plaques/nodules
- +/- eroded or ulcerated surface
- +/- crust
- Any site but especially caudal thighs (linear), oral cavity, lips
B. Eosinophilic plaque
- Raised, flat-topped erythematous plaques
- Usually ulcerated/eroded and pruritic
- Usually ventral abdomen/caudal thigh
- Secondary bacterial infection common
C. Indolent ulcer (‘rodent ulcer’)
- Erosive/ulcerated lesion on mucocutaneous junction of upper lips
- Unilateral/bilateral
- Rarely painful or pruritic
What are the three most common causes of feline reaction patterns?
- FAD – flea allergic dermatitis
- FFA – feline food allergy
- FASS – feline atopic skin syndrome
What are the differnetials of millary dermatitis?
Most likely to be FAD, FFA, FASS
* Dermatophytosis
* Pyoderma
* Cheyletiella, Neotrombicula, Otodectes
* (Pemphigus foliaceus)
What are the differntials of eosinophilic granuloma complex in cats?
Most likely to be FAD, FFA, FASS
* Cowpox
* Mycobacterial infections
* Neoplasia (cut lymphoma, MCT, SCC)
* Deep bacterial infections
* Fungal disease
* Respiratory viruses
* Insect bite HS
What are the differntials of face head and neck pruritus in cats?
Most likely to be FAD, FFA, FASS
* D cati,
* Otodectes
* Insect bite HS
- Dermatophytosis
- Malassezia dermatitis
- Respiratory viruses
- Bacterial pyoderma
- Pemphigus foliaceus
- Skin neoplasia (MCT, SCC, cut lymphoma)
- Drug reactions (methimazole)
- Idiopathic facial dermatitis (Persians)
- FOPS (esp Burmese)
What are the differntials of Self-induced alopecia in cats?
Most likely to be FAD, FFA, FASS
* **D gatoi **
* Dermatophytosis
* Malassezia dermatitis
* Feline paraneoplastic alopecia
* Psychogenic alopecia
* FLUTD/pain/neuralgia
What is the age of onset of the following?
* Demodicosis
* Other ectoparasites
* Environmental AD
* Food induced AD
* Endocrinopathies (secondary infection –> pruritus)
* Neoplasia
- Demodicosis - Young (< 1yo) and old - immunocompromise
- Other ectoparasites - Any age
- Environmental AD - 6mo- 3 year
- Food induced AD - any age but 30-50% < 1yo
- Endocrinopathies (secondary infection → pruritus) - Middle-aged-older
- Neoplasia - Older
In what species is sarcoptic mange more common in?
dog
What is the breed desposition for demodicosis and Canine AD?
Demodicosis - Staffordshire bull terrier, Shar pei . Canine AD - Terriers, Labradors, French bulldogs
What is your top dd for a Dog with dull coat, lethargy and bradycardia?
hypothyroidism
What is your top dd for a
Dog with diffuse thinning of coat, PUPD, polyphagia?
hyperadrenocorticism
Why may endocrinopathies present as pruritus?
Secondary microbial infection due to immunocompromise
What are the dd for pustules?
- Usually - superficial pyoderma (staphylococcal folliculitis)
- Uncommonly - demodicosis, dermatophytosis, pemphigus foliaceus (PF)
- Rarely – other sterile pustular diseases
What are the dd for epidermal collarettes, crusts?
Usually - superficial pyoderma
Occasionally - PF
What is the to dd for a dog with Lesions affecting caudal and dorsal regions in dog?
FAD top d/d!
What is the first step when dealing with a pruritic dog?
Eliminate ectoparasites and microbial dysbiosis/infections
- Investigate parasites: Confirmed or suspected –>Treat as appropriate (don’t believe a negative test –> thorough treatment trial if not on good (ideally isoxazoline) regime already)
- cytology: for microbial dysbiosis/infection - treat if confirmed
After elimination of ectoparasites and infection what does it mean in pruritis resolves fully?
implies non-pruritic underlying cause
- e.g. immunosuppressive disease: including endocrinopathy –> investigate as appropriate
- or ectoparasites, if not previously on good ectoparasite control –> continue ectoparasite control
After elimination of ectoparasites and infection what does it mean in pruritis remains?
implies other pruritic underlying disease
usually atopic dermatitis (environmental or food-induced)
How do you Distinguish between environmental and food-induced AD ?
Exclusion diet trial
* Exclusion diet needs to be fed for 8 weeks minimum
Environmental atopic dermatitis (FASS* in cat) diagnosed by exclusion
How can you use of prednisolone or oclacitinib to shorten time to diagnosis of food allergy?
Treat for initial 2-3 week, then stop to observe response
* pruritus recurs –> resume prednisolone/oclacitinib –> repeat cycles of treatment/observation to end of trial
* no pruritus for 2 weeks –> rechallenge with old diet)