Differential diagnosis of feline symmetricalalopecia (Proceedings)

Article

A symptom of several possible underlying diseases; Not a specific disease entity. A result of excess symmetrical licking with the barbs of the tongue fracturing the hair shafts; rarely is the alopecia spontaneous.

Feline symmetrical alopecia

  • Etiology

  • A symptom of several possible underlying diseases; Not a specific disease entity. A result of excess symmetrical licking with the “barbs” of the tongue fracturing the hair shafts; Rarely is the alopecia spontaneous.

  • Clinical Features

  • A non-inflammatory, symmetrical alopecia.

  • Most commonly affects the ventral abdomen, inguinal region, perineum, dorsal lumbosacral region, medial and posterior thighs; May also affect the entire ventrum, anterior and medial forelegs.

  • May affect “anywhere the cat can lick”.

  • Close inspection reveals diffuse thinning of hair rather than “total” alopecia. Owner often unaware of excess grooming behavior.

  • May be “secretive” or nocturnal groomers; Problem with “hair balls”.

  • Flea Allergy Dermatitis

  • Most commonly affects the dorsal lumbo-sacral region, caudo-medial thighs, ventral abdomen, and flanks.

  • Warm weather seasonal or non-seasonal pruritus – geographic differences.

  • Cutaneous Adverse Food Reactions - “Food Allergy”

  • Often affects the ventral abdominal, inguinal regions.

  • May also have “miliary lesions” in the pre-aural region, pinnae, neck, periorbital region, and face.

  • Non-seasonal pruritus, concurrent GI signs rare!

  • Atopic Dermatitis (“Catopy”)

  • Most commonly affects the medial thighs, entire ventrum, forelegs.

  • May mimic the distribution patterns of Flea Allergy or Food Allergy.

  • May be warm weather seasonal, present year round with exacerbations in warm weather, or non-seasonal.

  • Parasitic Causes

  • Cheyletiellosis (“Walking Dandruff”) - affects primarily the dorsal trunk with excess scaling a major sign. Symmetrical alopecia of the ventral abdomen.

  • Demodicosis - Demodex gatoi – short stubby mite. Symmetrical alopecia of the ventral abdomen.

  • Otoacariasis (Ectopic Ear Mites) - may mimic the distribution patterns of Flea Allergy, Food Allergy, or Atopy. Usually has concurrent otitis externa.

  • Pediculosis (Lice) - Felicola subrostrata. Affects primarily the dorsal trunk. Presence of “nits” on hair shafts.

  • Cat Fur Mite - Lynxacarus radovsky. Affects primarily the dorsal trunk. “Salt and pepper” like scale.

  • Intestinal Parasite Hypersensitivity - roundworms, hookworms, whipworms, tapeworms, Coccidia. May mimic the distribution patterns of Flea Allergy, Food Allergy, or Atopy.

  • Fungal Causes

  • Dermatophytosis - most commonly has areas of “patchy” alopecia, scales. History of other pets or humans in the household with skin lesions.

  • Malassezia Dermatitis - secondary complication. Brownish discoloration to the skin.

  • Miscellaneous Causes

  • Hyperthyroidism - excess grooming from “hyperexcitable” behavior.

  • Lower Urinary Tract Infections - affects the ventral abdomen.

  • Impacted anal glands (Anal sacculitis) - affects the perineal, perianal region.

  • Endocrine Causes

  • Hyperadrenocorticism - spontaneous symmetrical, truncal alopecia, easily epilated hairs. May have concurrent “skin fragility”.

  • Hypothyroidism - ????

  • Neoplastic Causes

  • Pancreatic Paraneoplastic Alopecia - geriatric cats. Alopecia most commonly on the ventrum and legs. Skin takes on a “shiny” appearance. Easily epilated hairs. Concurrent anorexia, lethargy.

  • Psychogenic Causes

  • Feline Psychogenic Alopecia - an anxiety neurosis. Often due to a disturbing influence. New puppy or kitten, barking dogs, new baby, recent move, etc. Emotional breeds: Burmese, Siamese, Abyssinian. Sequela to previous pruritic skin disease. Most commonly affects the easiest areas to reach; medial thighs, ventral abdomen, medial forelegs. Darkened hair color in Siamese cats due to melanin pigment increase with cooler skin temperature.

Feline symmetrical alopecia - diagnosis

  • Spontaneous vs. Post-traumatic alopecia

  • Physical exam - rarely is area completely alopecic, hairs do not easily epilate.

  • Trichogram - anagen bulbs with broken distal ends vs. telogen bulbs with fine pointed ends.

  • Feline Symmetrical Alopecia: Flea Allergy Dermatitis

  • Distribution pattern of lesions - posterior 1/3 of the body.

  • Seasonal pruritus.

  • Intradermal testing with flea antigen or in-vitro testing for flea.

  • Response to intense flea treatment protocol.

  • Feline Symmetrical Alopecia: Cutaneous Adverse Food Reactions -“Food Allergy”

  • Often affects the ventral abdominal, inguinal regions.

  • Non-seasonal pruritus.

  • Home cooked, novel protein and carbohydrate elimination diet 8-12 weeks in duration.

  • Protein Hydrolysate Diets

  • Reduced molecular weight (Daltons) of specific protein in diet.

  • Most “allergenic” proteins are in range of 14,000 – 70,000 Daltons.

  • Hydrolyzed proteins in the range of 1,000 – 12,000 Daltons.

  • Feline Commercial Protein Hydrolysate Diets

  • Royal Canin Veterinary Diet: Feline Hypoallergenic HP23 - hydrolyzed soy, chicken fat, rice, beet pulp, fish oil.

  • Hill's Prescription Diets: Feline z/d Low Allergen – hydrolyzed chicken and chicken liver, rice, vegetable oil.

 

  • Feline Symmetrical Alopecia: Atopic Dermatitis (“Catopy”)

  • Most commonly affects the medial thighs, entire ventrum, and forelegs.

  • Seasonal or non-seasonal pruritus.

  • Intradermal testing with aeroallergens.

  • Aeroallergen specific IgE immunoassay.

  • Feline Symmetrical Alopecia: Parasitic Causes

  • Most frequently Cheyletiellosis and Demodicosis.

  • Skin scrapings, Scotch tape preparations, flea combing, fecal flotation, vacuum technique.

  • Response to empirical parasiticidal treatments. Lime sulfur dips vs. selamectin vs. ivermectin vs. fipronil spray.

  • Feline Symmetrical Alopecia: Dermatophytosis

  • Most commonly have areas of “patchy” alopecia, scales.

  • History of other pets or humans in the household with skin lesions.

  • Wood's lamp examination, KOH prep, fungal cultures, skin biopsy.

  • Feline Symmetrical Alopecia: Hyperthyroidism

  • Basal total serum thyroxine (T4).

  • Feline Symmetrical Alopecia: Lower Urinary Tract Infections

  • Urine culture and susceptibility.

  • Feline Symmetrical Alopecia: Impacted anal glands (Anal sacculitis)

  • Anal gland extirpation.

  • Feline Symmetrical Alopecia: Hyperadrenocorticism

  • Spontaneous symmetrical, truncal alopecia, easily epilated hairs.

  • May have concurrent “skin fragility”.

  • Dexamethasone suppression test - 0.1 mg/kg – baseline, 4 & 8 hours post dexamethasone.

  • ACTH stimulation test - measure both cortisol and progesterone.

  • Feline Symmetrical Alopecia: Pancreatic Paraneoplastic Alopecia

  • Geriatric cats with alopecia most commonly on the ventrum, legs.

  • Skin takes on a “shiny” appearance.

  • Histopathology - marked follicular atrophy with a mild mononuclear perivascular dermatitis.

  • Abdominal ultrasound.

  • Serum trypsin-like immonoreativity (TLI).

  • Feline Symmetrical Alopecia: Feline Psychogenic Alopecia

  • History of change in cat's environment.

  • Non-responsive to Prednisolone.

  • Elizabethan collar response test.

  • Histopathology - normal or very mild superficial perivascular dermatitis.

Feline symmetrical alopecia – treatment

  • Flea Allergy Dermatitis

  • Environmental treatment - pyrethroid + pyriproxifin; boric acid or sodium polyborate powder.

  • Patient treatment - Imidacloprid – q14d + leufenuron – q30d; Fipronil + methoprene – q21d.

  • Aqueous hyposensitization with flea salivary antigen.

  • Cutaneous Adverse Food Reactions – “Food Allergy”

  • Commercial diet avoiding the known offending food source.

  • Royal Canin Veterinary Diet: Feline Sensitivity RD30 dry – duck, rice, chicken fat, vegetable oil         

  • Royal Canin Veterinary Diet: Feline Sensitivity VR canned – venison, rice.

  • Hill's Prescriptions Diets: Feline d/d – Canned – lamb and rice.

  • IVD – Limited Ingredient Diets - Feline Diets – duck, rabbit, venison, or lamb and green pea – canned or dry.

  • Home-cooked Treatment Diets - “novel” protein and carbohydrate source, essential fatty acid dietary supplement, safflower oil, dicalcium phosphate, non-flavored, additive free vitamin and mineral supplement, and taurine for cats.

  • Atopic Dermatitis (Catopy)

  • Allergen specific immunotherapy (ASIT).

  • Prednisolone (not Prednisone) - 1 mg/kg q12h x 7 d, then q24h x 7 d, then q48h at lowest possible dose to control pruritus.

  • Graham-Mize CA, Rosser EJ, Hauptman J: Absorption, bioavailability and activity of prednisone and prednisolone in cats. Adv Vet Derm, vol. 5: 152-158.Greater than a 6-fold difference in Cmax of oral prednisolone (Cmax= 1400 ng/ml) vs. oral prednisone (Cmax= 220 ng/ml); Cmax of oral prednisolone after oral prednisone only 122 ng/ml.

  • Results indicate both a decreased gastrointestinal absorption of prednisone compared to prednisolone, and possible decreased conversion of prednisone (inactive form) to prednisolone (active form) by the liver in cats.

  • Cyclosporine – 5 mg/kg q24h.

  • Parasitic Diseases

  • Lime sulfur – q7d x 4 weeks - Cheyletiella, Notoedres, Trombicula, Lynxacarus, Demodex gatoi, Felicola subrostrata.

  • Selamectin – q14d x 3 treatments - Cheyletiella, Notoedres, Otodectes.

  • Fipronil spray – q30d - Cheyletiella, Notoedres, Felicola subrostrata.

  • Ivermectin - 200 ug/kg q7d x 4 weeks - Cheyletiella, Notoedres, Otodectes; 200-300 ug/kg q24h - Demodex cati.

  • Amitraz – 125 ppm q14d - Cheyletiella, Notoedres, Trombicula, Lynxacarus, Demodex gatoi, Demodex cati, Felicola subrostrata.

  • Dermatophytosis: Systemics

  • Itraconazole - 5-10 mg/kg q24h with food for 4-6 weeks.

  • Terbinafine - 30 mg/kg q24h for 4-6 weeks.

  • Lufenuron - 60-100 mg/kg q30d x 2 treatments.

  • Dermatophytosis: Topicals

  • Lime sulfur - twice weekly for 4-6 weeks.

  • Enilconazole topical solution (10%) - twice weekly for 4-6 weeks.

  • Miconazole shampoo and leave on rinse 2% (ResiZole) - twice weekly for 4-6 weeks.

  • Hyperadrenocorticism

  • Unilateral/Bilateral adrenalectomy - Mineralocorticoid maintenance: Fludrocortisone acetate – 0.1-0.3 mg/cat or Desoxycorticosterone pivalate – 2.2 mg/kg SQ once monthly. Glucocorticoid maintenance: Prednisolone – 1.25-2.5 mg/cat/day

  • Metyrapone – 65 mg/kg q12h.

  • Pancreatic Paraneoplastic Alopecia

  • Screen for evidence of metastasis.

  • Radiographs and ultrasound - liver, diaphragm, lungs.

  • Partial pancreatectomy.

  • Feline Psychogenic Alopecia

  • Correct or remove disturbing influence.

  • Mood altering drugs

  • Clomipramine – 1.25-2.5 mg/cat/d.

  • Amitriptyline – 5 mg/cat q12h.

  • Hydroxyzine – 10 mg/cat q12h.

  • Paroxetine HCl – 2.5 mg/cat q24h.
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