L118: feline dermatoses

what is your rule out order for feline pruritic diseases?

1. parasitic diseases

2. infectious

3. allergic diseases

4. psychogenic dermatosis

what parasitic diseases cause feline pruritus?

1. fleas

2. notoedric mange

3. otodectic mange

4. cheyletielllosis

5. demodicosis (D. gatoi)

what infections can lead to feline pruritus?

1. dermatophytosis

2. malassezia

3. bacterial infections

4. herpes viral dermatosis

what allergic diseases can lead to feline pruritus?

1. FAD

2. mosquito bite hypersensitivity

3. food allergy

4. FASS

what are the various presentations of pruritic dermatoses in cats called?

cutaneous reaction patterns

where do we see pruritus in feline cutaneous reaction patterns?

1. head

2. face

3. neck

what lesions do we see with feline cutaneous reaction patterns?

1. excoriations

2. crusts

3. alopecia

4. miliary dermatitis (on the dorsum)

5. eosinophilic granuloma complex

where do we see alopecia from overgrooming in feline cutaneous reaction patterns?

symmetrical truncal, flank, and inguinal

what are the characteristics of eosinophilic plaques?

1. raised lesions

2. surfaces often eroded

3. bacterial overgrowth is common

what are the locations of eosinophilic plaques?

1. ventrum

2. medial thighs

how is pruritus with eosinophilic plaques?

always present

what is shown in the image?

eosinophilic plaques

what is shown in the image?

eosinophilic plaques

what are the most diverse of all the eosinophilic granuloma complexes?

eosinophilic granuloma

what are the locations of eosinophilic granulomas?

1. nodules or plaques → oral cavity, haired skin

2. linear plaques → caudal thighs

where will eosinophilic granulomas not present with pruritus?

1. ventral aspect of lip

2. tongue

what is shown in the image?

eosinophilic granulomas

what is shown in the image?

eosinophilic granulomas

what is shown in the image?

eosinophilic granulomas

what is shown in the image?

eosinophilic granulomas

what is shown in the image?

eosinophilic granulomas

what are the characteristics of indolent ulcers?

unilateral or bilateral ulcers typically with erythematous border and a necrotic center

where are indolent ulcers located?

lips

what is the pruritus with indolent ulcers?

none

what is shown on the following histopathology?

eosinophilic lesion

what other diseases cause eosinophilic inflammation?

1. feline herpes virus

2. mosquito bite hypersensitivity

what must you additionally consider if you are presented with a cat with an eosinophilic granuloma complex?

allergy work up

what are the minimum dermatological tests when you have a pruritic cat?

1. skin scrapings

2. trichoscopy

3. cytology of lesions

4. wood’s lamp ± fungal culture

what do you do in your allergy work up in a cat with pruritus?

1. ectoparasite control

2. elimination diet trial

3. diagnosis of FASS by exclusion

what type of reaction is a mosquito bite hypersensitivity?

type 1

when do we see mosquito bite hypersensitivity?

warm weather/seasonal

where do we see mosquito bite hypersensitivity?

1. pinnae

2. bridge of nose

3. pads of feet/digits

what lesions do we see with mosquito bite hypersensitivity?

1. symmetric miliary dermatitis

2. “moth-eaten” appearance of alopecia, ulcers, and erosions

what is used in the diagnosis of mosquito bite hypersensitivity?

1. history of exposure that resolves with avoidance

2. histopathology to rule out autoimmune disease

what is shown in the image?

mosquito bite hypersensitivity

what is the treatment for mosquito bite hypersensitivity?

1. avoidance of mosquitos

2. antiprutics or anti-inflammatory drugs

3. allergy-specific immunotherapy

which drug has FDA approval for treatment of allergic diseases in cats?

cyclosporine

what insecticide should never be used on or around cats due to toxicitiy?

permethrin

what anti-inflammatory drugs can be given in cats with allergies?

1. glucocorticoids

2. oclacitinib

what immunomodulatory drugs can be given in cats with allergies?

1. oclactibib

2. cyclosporine

what immunosuppressive drugs can be given in cats with allergies?

1. cyclosporine

2. glucocorticoids

what is psychogenic alopecia?

compulsive disorder of over grooming

what breed is predisposed to psychogenic alopecia?

fancy breeds

what is used for the diagnosis of psychogenic alopecia?

1. diagnosis of exclusion, including FASS

2. glucocorticoid trial to rule out inflammatory diseases

what clinical signs are seen with psychogenic alopecia?

1. bilaterally symmetrical alopecia

2. usually no associated secondary infections

where do we typically see alopecia with psychogenic alopecia?

1. ventral abdomen

2. medial thigh

3. flank

what is the treatment for psychogenic alopecia?

1. removal from stressors

2. environmental enrichment

3. behavior modification

4. anxiety medications

what is feline hyperesthesia syndrome?

episodic lumbar skin hypersensitivity

what does feline hyperesthesia syndrome look a lot like?

FASS → required diagnosis of exclusion

what is feline herpesviral dermatosis?

herpesvirus-1 (FHV-1) remains latent in sensory nerve ganglia that can reactivate

what are flare factors for feline herpesviral dermatosis?

1. stress

2. overcrowding

3. immunosuppressive drugs

what skin lesions may be seen with feline herpesviral dermatosis?

1. ulcers

2. redness

3. crusting

4. inflammation

where do we see skin lesions with feline herpesviral dermatosis?

1. nose

2. face

3. eyelids

4. paws

what are the respiratory signs with feline herpesviral dermatosis?

1. sneezing

2. nasal discharge

what ocular signs are seen with feline herpesviral dermatosis?

1. conjunctivitis

2. corneal ulcers

3. light sensitivity

what general clinical signs can be seen with feline herpesviral dermatosis?

1. lethargy

2. fever

3. hyporexia to anorexia

what can feline herpesviral dermatosis look identical to?

1. mosquito bite hypersensitivity

2. eosinophilic granuloma

what is used in the diagnosis of feline herpesviral dermatosis?

1. clinical signs

2. cytology

3. biopsy

4. PCR testing

what is shown in the cytology?

feline herpesviral dermatosis

what is the treatment for feline herpesviral dermatosis?

1. antivirals

2. supportive care

3. stress reduction

4. manage pain with gabapentin

what treatment can help stop viral replication with feline herpesviral dermatosis?

famciclovir

what is feline chin acne?

idiopathic disorder of follicular keratinization and glandular hyperplasia

what is the signalment for feline chin acne?

1. median age is 4

2. frequently seen in cats with FASS

what are the clinical signs of feline chin acne?

1. comedones

2. alopecia

3. crusts

4. papules

5. erythema on chin

6. comissures of lips

what bacteria is common with feline chin acne?

1. staphylococcus

2. streptococci

what is used in the diagnosis for feline chin acne?

1. clinical presentation

2. histopathology

what is shown on the histopathology?

feline chin acne

what is the mild treatment for feline chin acne?

topical therapy → medicated wipes

what is the moderate treatment for feline chin acne?

topical therapy → antibiotic ointment, benzoyl peroxide gel

what is the severe treatment for feline chin acne?

systemic antibiotics and glucocorticoids

what breeds do we see idiopathic facial dermatitis (dirty face syndrome)?

1. persians

2. himalyans

what are the clinical signs of idiopathic facial dermatitis?

dirty appearance with black waxy exudate adhered to skin and hair confined to face and head

when will idiopathic facial dermatitis become pruritic?

if there is a Malassezia infection present

what is used in the diagnosis of idiopathic facial dermatitis?

1. signalment and clinical presentation

2. cytology to assess for secondary infection

what is shown in the image?

idiopathic facial dermatitis

what is the treatment for idiopathic facial dermatitis?

1. address secondary infections → antimicrobial wipes

2. severe cases → oral glucorticoids and/or cyclosporine

what is plasma cell pododermatitis (pillow foot)?

severe plasma cell-rich perivascular inflammation targeting multiple footpads

what is shown in the image?

plasma cell pododermatitis

what are the clinical signs of plasma cell pododermatitis?

1. scaling to purple-hued swelling of footpads (often central pad)

2. superficial erosions/ulcers

3. severe cases may rupture

4. old lesions may look deflated, mushy

what does the histopathology show?

plasma cell pododermatitis

what is used in the diagnosis of plasma cell pododermatitis?

1. clinical diagnosis

2. cytology

3. histopathology

4. hypergammaglobulinemia common

what is used in the treatment of plasma cell pododermatitis?

1. prednisolone

2. doxycycline

3. cyclosporine

what patients do we see hyperthyroidism in?

older cats 6-20 years

what are the dermatologic signs of hyperthyroidism in cats?

1. unkempt coat

2. focal or symmetric alopecia

3. increased claw growth

4. dry or greasy skin coat

5. cutaneous atrophy in chronic cases

what is used for the diagnosis of hyperthyroidism?

1. history and clinical signs

2. elevated total T4

what medication is given for hyperthyroidism?

methimazole

what are the endogenous causes of hypercortisolism?

1. PDH

2. hyperadrenocorticism

what other condition do cats with hypercortisolism typically have?

diabetes mellitus

what are the clinical signs of hypercortisolism?

1. alopecia

2. cutaneous atrophy

3. bruising

4. folded pinnae → iatrogenic form

what is the signalment for paraneoplastic alopecia (mirror belly)?

older cats (>10 years)

what is paraneoplastic alopecia most frequently associated with?

pancreatic carcinoma

what are the clinical signs of paraneoplastic alopecia?

1. prominent alopecia

2. smooth shiny skin

3. adherent brown scale

4. Malassezia dermatitis common

what is used in the diagnosis of paraneoplastic alopecia?

1. classic shiny alopecic belly

2. diagnostic imaging

3. histopathology

what is the prognosis for paraneoplastic alopecia?

guarded

what is shown in the image?

paraneoplastic alopecia