Difference between revisions of "Skin Other - Pathology"

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

Latest revision as of 18:33, 22 February 2011