Feline Dermatology

FELINE DERMATOLOGY

Introduction Compound follicles – greater number of secondary hairs  Less contact dermatitis Epidermis – very thin  Careful with topical therapy – shampoos Lack melanocytes except on lip, footpad, nose, scrotum and circumanal  Lentigo Simplex Dorsum of tail – collection of sebaceous glands  Feline stud tail Inflammatory response different  Less folliculitis  Response to steroids, decreased (higher doses)

Feline Acne Comedones to folliculitis/furunculosis to chin edema Etiology – unknown. Seborrheic disorder? Infection – secondary in more chronic cases

Feline Acne Clinical signs  Comedones

on chin and lips  Erythematous papules and pustules  Folliculitis/furunculosis/cellulitis of chin with hemorrhagic exudate  Pruritus variable  Severity of disease variable  Fat Chin – swelling – part of EGC

Feline Acne Diagnosis  Clinical

signs  Rule out demodex, dermatophyte, contact (?), Malassezia derm and food allergy – if pruritic  Bacterial culture/sensitivity if exudative  Biopsy(?)

Feline Acne Treatment  DO

NOT OVERTREAT!!!!!!!!!!!  Do nothing if black heads (pick it off)  Clip, warm soaks and gentle washings  Systemic antibiotic for pustular/infected  Recurrent cases – Topical Vitamin A?

Mycobacterial Infections Higher bacteria – mostly saprophytes Non tuberculosis/non leprosy – atypical Atypical  Ubiquitous

saprophytes – classified according to culture characteristics  Can be opportunists  Type IV – rapid growing M. fortuitum most common

Atypical Mycobacterial Infections Clinical signs  Single

or multiple SQ nodules, ulcerate and drain  Chronic non-healing and draining wounds, non-responsive to surgery or antibiotics  Both types tend to recur and cause dehiscence of suture line – may enlarge after attempt to “cut it out”

Atypical Mycobacterial Infections Diagnosis  Can

be difficult  History  Culture – special media – alert lab; Sensitivity  Biopsy – special stains – very few organisms! – Pyogranulomatous panniculitus

Atypical Mycobacterial Infections Treatment  Antibiotics

– based on C & S; however invivo and in-vitro don’t always match  Aminoglycosides – toxicity  Sodium iodide therapy?  Lamprene 8 mg/kg SID  Long term fluoroquinolone – Not Baytril – retinal problems/blindness

Sporotrichosis Cats are unique – high numbers of organisms Zoonotic potential highest in cats Handle carefully

Flea Allergy Dermatitis Clinical signs – not as classic as dogs Lumbosacral dermatitis – like dogs Facial or generalized pruritus Self-inflicted alopecia  Bald

belly cat

******Miliary dermatitis Miliary dermatitis – collar only

Cutaneous Reaction Pattern Based Diagnosis Cats respond to cutaneous insults in a limited number of ways Diagnosis helped by recognizing reaction pattern – use to make DDX list Most patterns have similar list – but order of probability is different

Cutaneous Reaction Pattern Based Diagnosis Miliary dermatitis Eosinophilic Granuloma Complex Head and Neck Pruritus Scaling/Crusting Self-inflicted alopecia

Cutaneous Reaction Pattern Based Diagnosis Miliary dermatitis Eosinophilic Granuloma Complex Head and Neck Pruritus Scaling/Crusting Self-inflicted alopecia

Miliary Dermatitis Very common clinical presentation VERY LONG DDX LIST

Miliary Dermatitis FLEA ALLERGY Food allergy Atopy Otodectic mange Cheyletiellosis Trombiculidiasis Notoedric mange Demodectic mange Dermatophytosis Staph folliculitis

Pediculosis Ticks Cat fur mite Drug eruption Internal parasitism Hypereosinophilic syndrome Biotin deficiency Fatty acid deficiency Hormonal Idiopathic

Miliary Dermatitis Clinical Signs Papule surmounted by a crust Edematous – exudes serum Distribution is variable Pruritus is variable/self inflicted alopecia

MILIARY DERMATITIS Diagnosis Clinical signs Search for underlying etiology – initially..  Skin

scrape  Ringworm culture  Fecal exam  Flea allergy test/flea control

MILIARY DERMATITIS Further work up Antibiotics for several weeks Food allergy trial Intradermal skin test CBC Response to ivermectin Intestinal parasite deworming Discontinue drugs Biopsy?

MILIARY DERMATITIS Treatment Treat underlying disease Steroids (rule out demodex, dermatophyte, staph) 1 mg/lb prednisone daily then taper 10 – 20 mg Depo-medrol EOM or less! Ovaban/Megace????? YUCK

Cutaneous Reaction Pattern Based Diagnosis Miliary dermatitis Eosinophilic Granuloma Complex Head and Neck Pruritus Scaling/Crusting Self-inflicted alopecia

SYMMETRICAL ALOPECIA Self-inflicted alopecia- MUCH MORE COMMON THAN….. Non self inflicted alopecia Self –inflicted  Pruritic

(VERY COMMON)*****  Psychogenic (MUCH LESS COMMON)

SYMMETRICAL ALOPECIA Various areas affected Ascertain if hair loss is self inflicted  Historical

information: owner noting licking, chewing etc..  History or hair balls or constipation  Derm exam: hair epilation, broken hair, dermatitis?  Exam hairs microscopically  E-collar (usually not needed)

SYMMETRICAL ALOPECIA If self-inflicted then: pruritic vs psychogenic Explore pruritic disease first Skin scrape, fungal culture, fecal exam, flea test/control If no answer then.. Food trial, skin testing, ivermectin response, deworming

SYMMETRICAL ALOPECIA Treatment Treat underlying pruritic disease After extensive search then try steroids  Steroids

may help to differentiate between pruritic and psychogenic alopecia

SYMMETRICAL ALOPECIA Psychogenic High strung breeds: Siamese, Burmese, Abyssinian, Himalayan Historical informationchange in physical or mental environment R/O self inflicted pruritic

PSYCHOGENIC Alleviate the stressor Mood modifying drugs Most commonly used  Prozac

(Fluoxetine)  Elavil (Amitriptylline)

Taper gradually

NON SELF INDUCED ALOPECIA Temporary stresses: antimitotic drugs, surgery, high fever Systemic Disease Cushing’s  Diabetes  Hyperthyroid  Advanced kidney disease  Chronic hepatic disease  Paraneoplastic alopecia 

Cutaneous Reaction Pattern Based Diagnosis Miliary dermatitis Eosinophilic Granuloma Complex Head and Neck Pruritus Scaling/Crusting Self-inflicted alopecia

HEAD AND NECK PRURITUS Extremely pruritic!!!! May need steroids initially or placement of E- collar because of self trauma Difficult to make diagnosis DDX: Otodectes, Notoedres, Food Allergy, Atopy, Flea Allergy, Dermatophyte, Demodex, Other Ear Disease

SEBORRHEIC DISEASE Total body seborrhea: systemic disease, chronic inflammatory dz, FeLV, FIV, malnutrition, environmental problem, endocrinopathy Sticky cat syndrome – idiopathic Localized seborrhea: feline acne and stud tail

SEBORRHEIC DISEASE Stud tail Most common – intact males Comedones/inflammation of dorsal sebaceous glands Treatment: ignore, wash with benzoyl peroxide, treat with antibiotics, treat with ketoconazole

PLASMA CELL PODODERMATITIS Rare idiopathic disease Footpad swelling – sometimes ulceration May occur with hyperglobulinemia, lymphocytosis, GN Soft non-painful pad swelling, pads balloon and then collapse, may then ulcerate and be painful

PLASMA CELL PODODERMATITIS Diagnosis Histopathology: massive plasma cell infiltration R/O neoplasia, autoimmune Treatment: glucocorticoids, possibly gold salts

LENTIGO SIMPLEX Orange cats: Macular areas of hyperpigmentation Lips, eyelids, gingiva and nose Completely asymptomatic

STEROIDS Cats harder to pill More resistant to adrenal suppression Don’t respond as well to oral steroids Iatrogenic Cushings is rare Commonly use long acting injectables: Depo-Medrol, Vetalog

MEGESTEROL ACETATE Megace, Ovaban More effective antiinflammatory agent than steroids in the cat Mood altering MANY SIDE EFFECTS: adrenal suppression, PP, PU/PD, personality changes, pyometra or stump pyometra, mammary gland cysts or hyperplasia, DM