Feline Dermatoses I PDF

Feline Dermatoses I VCS 80610 - Small Animal Medicine I PAULO GOMES, DVM, DACVD COLLEGE OF VETERINARY MEDICINE CLINICAL PROFESSOR OF VETERINARY VETERINARY DEPARTMENT OF VETERINARY CLINICAL SCIENCES Outline Ø Abscesses Ø Feline Plasma Cell Pododermatitis Ø Inflammatory Polyps Ø Feline Solar Der...

Feline Dermatoses I VCS 80610 - Small Animal Medicine I PAULO GOMES, DVM, DACVD COLLEGE OF VETERINARY MEDICINE CLINICAL PROFESSOR OF VETERINARY VETERINARY DEPARTMENT OF VETERINARY CLINICAL SCIENCES Outline Ø Abscesses Ø Feline Plasma Cell Pododermatitis Ø Inflammatory Polyps Ø Feline Solar Dermatitis Ø Squamous Cell Carcinoma Ø Feline Paraneoplastic Syndrome Abscesses Ø Confined pocket of pus in tissues, organs, or spaces inside the body. Usually caused by a bacterial infection Ø Subcutaneous abscesses ü Common in cats, specially among intact male cats ü Cat fight or bite abscesses ü Less common in dogs Ø Occurs when normal oral bacterial microflorae are inoculated into the skin through puncture wounds Ø In cats: Pasteurella multocida is commonly associated with bite wounds Abscesses Feline abscess: subcutaneous swelling causesd by a cat bite. Abscesses Ø Lesions ü Localized, painful, swelling with a crusted-over puncture wound ü Purulent material may drain ü Commonly found on the tail base, shoulder, neck, face, or legs Ø Regional lymphadenomegaly Ø Fever, anorexia, and depression Ø Cytology: suppurative inflammation with a mixed bacterial population Ø Differential diagnosis ü Foreign body, actinomycosis, nocardiosis, mycobateriosis, and neoplasia Abscesses Ø Treatment ü ü ü ü ü ü ü Clip and clean the affected area Lance the abscess and clean with chlorhexidine solution 0.025% Systemic antibiotic for 7 to 10 days Clavulanate-amoxicillin 22mg/kg PO q 8 to 12 h Amoxicillin 20mg/kg PO, SC, or IM q 8 to 12 h Clindamycin 10mg/kg PO or IM q12h Cefovecin 8mg/kg SC Ø Prognosis: good Ø Castrating intact male cats can be helpful Feline Plasma Cell Pododermatitis Ø Plasmacytic inflammatory disease of the footpads Ø Likely immune-mediated cause ü Persistent hypergammaglobulinemia, marked plasma cell tissue infiltration, and responsive to glucocorticoid therapy Ø Clinical signs ü ü ü ü ü ü Swelling of multiple footpads, soft and spongy Metacarpal and metatarsal pads are most commonly affected Footpads may ulcerate and bleed Pain and lameness in advanced stages Regional lymphadenomegaly may be seen Occasionally: swelling of the nose, plasmacytic stomatitis, immunemediated glomerulonephritis, or renal amyloidosis Plasma cell pododermatitis: Swollen metacarpal footpad with moderate hyperkeratosis. Bruise of the deep tissues. Pads can be soft and spongy to touch. Feline Plasma Cell Pododermatitis Ø Differential Diagnoses ü Eosinophilic granuloma, bacterial and fungal granuloma, mosquito bite hypersensitivity, and autoimmune disorders Ø Cytology ü Numerous plasma cells, with fewer lymphocytes and neutrophils Ø Dermatohistopathology ü Perivascular to diffuse dermal infiltration with plasma cells ü Variable number of lymphocytes and neutrophils Feline Plasma Cell Pododermatitis Ø Treatment ü Any underlying allergy should be identified and managed ü Systemic glucocorticoids are usually effective 4mg/kg PO SID until lesions are resolved, then gradually tapered off ü Cyclosporine 5-10mg/kg PO SID (cats should be FeLV and FIV negative, low risk of toxoplasmosis) ü Doxycycline 5-10mg/kg PO BID until remission; long term therapy may be necessary ü Bleeding ulcers may require surgical intervention Ø Prognosis ü Good for most cases Inflammatory Polyps Ø Non-neoplastic growths that originate in the middle ear mucosa or eustachian tube Ø Common in cats and uncommon in dogs Ø Well-vascularized fibrous tissue stroma Ø It is believed that polyps arise as a result of prolonged inflammation Ø Young mature cats are predisposed Ø The polyp may present as an otic polyp, nasopharyngeal, or both ü ü Nasopharyngeal polyps: the polyp extend into the pharynx via eustachian tube Otic polyps: the polyp extend into the ear canal via rupture of the tympanic membrane Polyps may extend either into the pharynx via the auditory tube (i.e. eustachian tube), or the external ear canal via rupture of the tympanic membrane. Inflammatory Polyps Ø Clinical signs ü ü ü ü ü ü Otic polyps are usually unilateral Otic discharge Secondary bacteria and yeast infections Head shaking In severe cases: head tilt, nystagmus and vestibular disease Nasopharyngeal polyps: labored and noisy breathing, nasal discharge, head shaking, sneezing, difficulty in swallowing Ø Diagnosis ü Otic Polyp: Careful flushing of the ear canal promotes a good visualization with and otoscope or video-otoscope ü Nasopharyngeal polyp: visualized by retraction of the soft palate on oral exam Inflammatory polyps PF M PT Normal feline tympanic membrane: Pars tensa (PT), Otic inflammatory polyp: Dome-shaped fleshy mass in the ear canal of a cat on video-otoscopy. Pars flaccida (PF), and Manubrium of Malleus on video-otoscopy. Inflammatory Polyps Ø Advanced imaging exam: CT, or MRI Inflammatory polyp in the right tympanic bulla extending to the external ear canal. CT scan of the head with contrast. Inflammatory Polyps A large nasopharyngeal polyp (green arrow) fills most of the throat, making it difficult for the cat to eat or breath. Inflammatory Polyps Ø Treatment ü Removal by traction • Firmly grasp the polyp with an alligator forceps or endoscopic forceps • For otic polyps the use of video-otoscope allows excellent visualization • The polyp may be rotated 90 degrees • A quick tug on the forceps will cause the thin vascular peduncle to break, enabling the mass to be removed intact • When the stalk is stretched by gentle traction the vascular supply to the polyp is destroyed and regrowth is unlikely • Topical corticosteroid solution is infused onto the tympanic bulla mucosal surface • Prednisolone therapy following removal by traction is recommended • Reoccurrence is variable (up to 50%) Inflammatory Polyps Ø Treatment ü Surgical removal • Ventral Bulla osteotomy is considered the most successful treatment option • The polyp is removed followed by curettage of tympanic bulla’s epithelial lining, and accumulated material • Minimal reoccurrence • Potential surgical complications: Horner's syndrome, vestibular disturbances, polyp regrowth, otitis media, hemorrhage, wound drainage, hypoglossal nerve damage, damage to auditory ossicles and vascular structures, and facial nerve paralysis Feline Solar Dermatitis Ø Actinic damage to mildly pigmented, non pigmented sparsely haired skin Ø Most often affects the apex of the ears in white cats Ø Occasionally affects the eyelids, nose and lips Ø Caused by repeated sun light exposure (UVB light) Ø The disease occurs mostly in warm, sunny climates Ø Can progress to actinic keratosis or squamous cell carcinoma Feline Solar Dermatitis Ø Clinical Features ü Erythema and fine scaling of pinnal margins in early stages ü Usually no discomfort is observed in the beginning ü Lesions become progressively severe each summer ü Advanced lesions: severe erythema, skin peeling, and crusts on the ear margins ü In advanced stages the lesions are painful and further damaged is caused by scratching ü The margins of the pinnae may curl ü The margin of the lower eyelids, nose and lips may be affected ü Carcinomatous changes: ulcerative, hemorrhagic, and locally invasive lesions Feline Solar Dermatitis Feline solar dermatitis: Alopecia, erythema, scaling, crusts, tissue loss, and actinic lesions on pinnae. Feline Solar Dermatitis Ø Diagnosis ü History of chronic sun light exposure ü Color of the cat ü Clinical appearance ü Dermatohistopathology • Detects dysplastic or neoplastic changes • Differential diagnosis are excluded by biopsy ü Differential diagnosis • Dermatophytosis, notoedric mange, fight wounds, vasculitis, discoid or systemic lupus erythematosus, pemphigus erythematosus, and pemphigus foliaceous Feline Solar Dermatitis Ø Clinical Management ü ü ü ü Keep the cat indoors Avoid sunbathe by open doors or windows Waterproof sunscreen in the summer Active carotenoids 25mg (β-Carotene and canthaxanthin) ü Cosmetic amputation of the apex of the ears ü For advanced lesions with actinic keratosis • • • • Retinoic acids Superficial irradiation therapy (plesiotherapy) Topical Imiquimod (2-3 times weekly) Radical amputation of the pinnae Feline Solar Dermatitis Feline solar dermatitis and actinic keratosis pre-op. Feline Solar Dermatitis Feline solar dermatitis and actinic keratosis: Post-op surgical CO2 laser ablation. Feline Solar Dermatitis Feline solar dermatitis and actinic keratosis: Post-op surgical CO2 laser ablation. Squamous Cell Carcinoma (SCC) Ø Malignant neoplasm of keratinocytes Ø Common in cats and less common in dogs Ø Most often occurs in sparsely haired (glabrous), nonpigmented, sun-damaged skin Ø Usually preceded by actinic (solar) keratosis Ø Sun-light induced tumors is higher in geographic areas with intense sunlight Ø Mutations in the tumor suppressor gene (p53), and overexpression of p53 protein may be involved in tumor development Squamous Cell Carcinoma (SCC) Ø Clinical features ü Proliferative, crusting or ulcerative lesions that may bleed ü In cats: non-pigmented pinnae, nose, and eyelids • • • • • Peak incidence between 9-14 years of age No breed or sex predilection White cats have a greater risk of developing SCC 80% of lesions are found on the head Primary SCC of the feline digit is rare ü In dogs: trunk, legs, digits, scrotum, nose, lips, and nails Squamous cell carcinoma: alopecia, erythema, erosions and crusts on the face, nose, eyelids and ear margin in a cat with slightly pigmented white haired skin. Squamous Cell Carcinoma (SCC) Ø Diagnosis Ø Cytology üOften nondiagnostic Ø Dermatohistopathology üAtypical keratinocytes that proliferate downward and invade the dermis Ø Screen lymph nodes and lungs for metastasis Ø Early surgical excision is the treatment of choice Ø Nonresectable lesions: chemotherapy (cisplatin, bleomycin, carboplatin, 5-fluoracil) Ø Avoid sunlight exposure Squamous Cell Carcinoma (SCC) Ø Prognosis ü Most tumors are locally invasive and slow to metastasize ü In cats the prognosis depends on the size and degree of differentiation • Smaller, well-differentiated tumors have a better prognosis • Large or poorly differentiated tumors have a guarded to poor prognosis Feline Paraneoplastic Syndrome Ø Characteristic alopecia associated with internal malignancy Ø Most often associated with pancreatic malignancy Ø Considered a unique feline syndrome ü A similar condition has not been described in human or canine dermatology Ø Highest incidence in older cats Ø Cause ü Adenocarcinoma (pancreatic or bile duct carcinoma) Ø The tumor does not involve the skin Ø Generally endocrine changes are not present Ø The pathophysiology of this syndrome in unknown Feline Paraneoplastic Syndrome Ø Clinical features ü Acute onset of rapidly progressive, bilaterally symmetrical alopecia ü The skin has a shinny and glistening appearance ü The skin is not fragile ü In nonalopecic area the hairs epilate easily ü Footpads may be painful, dry, soft, and fissured ü Pruritus may be related to secondary Malassezia dermatitis ü Concurrent systemic signs: anorexia, weight loss, lethargy, vomiting, diarrhea Feline paraneoplastic alopecia: extensive alopecia ventrally, involving distal extremities and face. Shiny skin is a striking feature of this disease. Feline paraneoplastic alopecia: extensive alopecia affecting the face. Note the paw with smooth pads. Feline Paraneoplastic Syndrome Ø Hematologic and biochemical test results are not indicative of underlying neoplasia Ø Skin biopsy with Dermatohistopathology is the preferred diagnostic test and typically reveal changes highly suggestive of this syndrome Ø The major differential diagnosis is hypercortisolism Ø X Ray and ultrasound may be helpful but usually fail to reveal an abdominal mass Ø The final diagnosis is usually made during exploratory laparotomy Feline Paraneoplastic Syndrome Ø Metastasis to the liver is common Ø Treatment of choice is complete surgical excision of the internal malignancy Ø Hair regrowth occurs after surgery Ø Prognosis ü Grave ü Metastasis to the liver or lungs has usually occurred by the time of the diagnosis