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− | {{review}}
| + | #REDIRECT[[:Category:Integumentary System - Pathology]] |
− | {{toplink
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− | |backcolour = FFCCCC
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− | |linkpage =Integumentary System - Pathology
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− | |linktext =Integumentary System
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− | |maplink = Integumentary System (Content Map) - Pathology
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− | |pagetype =Pathology
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− | }}
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− | <br>
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− | ==Epidermal growth or differentiation disorders==
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− | ===Seborrheic disease complex===
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− | *Abnormal cornification or function of sebaceous glands
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− | *Large amounts of free fatty acids and cholesterol
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− | *Decreased amounts of diester waxes in surface lipids
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− | *Bacterial population changes to pathogenic [[:Category:Staphylococcus species|coagulase positive staphylococci]]
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− | *Chronic disease affecting mainly dogs, sometimes cats and horses
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− | *Dry form - white to grey scales
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− | *Greasy form - scaly, excess brown to yellow lipids sticking to skin and hair
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− | | |
− | ===Primary idiopathic seborrhea===
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− | *Abnormal cornification
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− | *Epidermal turnover reduced to about 2/3 of normal
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− | *Microscopically:
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− | **Hyperkeratosis distending follicular ostia causing papillary appearance
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− | **Parakeratosis at edges of follicular ostia
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− | **Congested, oedematous dermal papillae
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− | **Spongiotic epidermis with leukocytes
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− | | |
− | ===Secondary seborrhea===
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− | *Develops secondarily to many types of disease (''e.g.'' [[:Category:Integumentary System - Parasitic Infections|ectoparasites]], [[:Category:Integumentary System - Mycotic Infections|fungal infections]], [[Endocrine effects on the skin - Pathology|endocrine disease]], internal disease or allergy)
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− | *Microscopically:
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− | **Hyperkeratosis and/or parakeratosis of follicles and epidermis
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− | **Lesions relevant to the other disease
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− | ===Sebaceous adenitis===
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− | *Inflammation of sebaceous glands, alopecia, hyperkeratosis
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− | *Possibly immune-mediated
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− | *Mainly affects dogs
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− | **Long haired show multifocal, serpiginous and annular lesions
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− | *Microscopically:
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− | **Inflammation of sebaceous glands
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− | **Possibly orthokeratotic hyperkeratosis
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− | **Chronic lesions are deprived of sebaceous glands and contain mild inflammation and fibrosis at follicular isthmus
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− | ==Pigmentation disorders==
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− | ===Hypopigmentation===
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− | *Leukoderma or vitiligo - loss of pigment in the skin
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− | *Leukotrichia - loss of pigment of the hair
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− | *Hypopigmentation or incomplete albinism - generalised reduction of pigment in skin or hair
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− | *Albinism - inherited lack of pigment
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− | *Dilution - reduced pigmentation
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− | *Can be localised or generalised, idiopathic or asociated with other diseases
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− | *Examples of hereditary conditions: Maltese dilution of cats, Chediak-Higashi syndrome, leukoderma and leukotrichia of Dobermans, Arabian fading syndrome
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− | *Asociated with some immune-mediated disorders, ''e.g.'' [[Skin Immunologic - Pathology#Lupus erythematosus|discoid lupus erythematosus]]
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− | ===Hyperpigmentation===
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− | [http://w3.vet.cornell.edu/nst/nst.asp?Fun=Image&imgID=1782 Image of endocrine hyperpigmentation from Cornell Veterinary Medicine]
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− | *Results from irritation or inflammation, pigmented neoplasms or [[Endocrine effects on the skin - Pathology|metabolic diseases]]
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− | *Lentigo - circumscribed macular or slightly raised plaque with epidermal hyperplasia and hyperpigmentation
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− | ==Eosinophilic infiltration==
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− | ===Eosinophilic plaques===
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− | *Common in cats
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− | *Medial thighs and abdomen mostly involved
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− | *Often associated with hypersensitivity
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− | *Grossly:raised plaques, erythematous, pruritic, erosed or ulcerated
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− | *Microscopically: acanthosis, spongiosis, erosions or ulceration, predominantly eosinophilic dermatitis, possibly areas of collagen degeneration
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− | ===Eosinophilic granulomas===
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− | *Involves cats, dogs, horses
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− | *Collagen degeneration in lesions os eosinophil degranulation
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− | *Often involved in reaction to parasites, foreigh bodies or mas cell tumours
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− | *Grossly:
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− | **Papules, nodules, plaques, ulcers in skin
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− | **Nodules or ulcers in oral mucosa of cats and dogs or on foot pads of cats
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− | *Microscopically:
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− | **Nodular dermatitis or stomatitis
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− | **Fragments of degenerated collagen surrounded by eosinophils and macrophages
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− | ===Eosinophilic folliculitis and furunculosis===
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− | *Rare in cats, dogs, cattle and horses
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− | *Possibly due to arthropod bites
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− | *May be multifocal in horses
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− | ==Sterile granulomatous disorders==
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− | ===Juvenile pyoderma===
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− | *Also known as '''Juvenile sterile granulomatous dermatitis and lymphadenitis, juveline cellulitis, puppy strangles'''
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− | *Involves dogs of less then 4 months of age
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− | *Grossly: pustular and nodular dermatitis with oedema involving the face, ears, mucocutaneous junctions
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− | *Microscopically: granulomatous or pyogranulomatous perifolliculitis, paniculitis and dermatitis
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− | ===Equine generalised granulomatous disease===
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− | *Also known as '''Sarcoidosis'''
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− | *In horses
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− | *Rare
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− | *Involves cutaneous lesions and systemic disease causing anorexia and weight loss
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− | *Grossly: alopecia, scales, crusts, sometimes nodules and masses
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− | *Microscopically: multifocal granulomas, multinucleated giant cells
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