Difference between revisions of "Skin Other - Pathology"

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[[Seborrhea]]
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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 [[:Category:Staphylococcus species|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.'' [[: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)
 
*Microscopically:
 
**Hyperkeratosis and/or parakeratosis of follicles and epidermis
 
**Lesions relevant to the other disease
 
  
 
===Sebaceous adenitis===
 
===Sebaceous adenitis===
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*Epidermal growth or differentiation disorder
 
*Inflammation of sebaceous glands, alopecia, hyperkeratosis
 
*Inflammation of sebaceous glands, alopecia, hyperkeratosis
 
*Possibly immune-mediated
 
*Possibly immune-mediated
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**Possibly orthokeratotic hyperkeratosis
 
**Possibly orthokeratotic hyperkeratosis
 
**Chronic lesions are deprived of sebaceous glands and contain mild inflammation and fibrosis at follicular isthmus
 
**Chronic lesions are deprived of sebaceous glands and contain mild inflammation and fibrosis at follicular isthmus
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==Pigmentation disorders==
 
==Pigmentation disorders==
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*Examples of hereditary conditions: Maltese dilution of cats, Chediak-Higashi syndrome, leukoderma and leukotrichia of Dobermans, Arabian fading syndrome
 
*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.'' [[Discoid Lupus Erythematosus|discoid lupus erythematosus]]
 
*Asociated with some immune-mediated disorders, ''e.g.'' [[Discoid Lupus Erythematosus|discoid lupus erythematosus]]
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===Hyperpigmentation===
 
===Hyperpigmentation===
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*Results from irritation or inflammation, pigmented neoplasms or [[Endocrine effects on the skin - Pathology|metabolic diseases]]
 
*Results from irritation or inflammation, pigmented neoplasms or [[Endocrine effects on the skin - Pathology|metabolic diseases]]
 
*Lentigo - circumscribed macular or slightly raised plaque with epidermal hyperplasia and hyperpigmentation
 
*Lentigo - circumscribed macular or slightly raised plaque with epidermal hyperplasia and hyperpigmentation
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==Eosinophilic infiltration==
 
==Eosinophilic infiltration==
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*Grossly:raised plaques, erythematous, pruritic, erosed or ulcerated
 
*Grossly:raised plaques, erythematous, pruritic, erosed or ulcerated
 
*Microscopically: acanthosis, spongiosis, erosions or ulceration, predominantly eosinophilic dermatitis, possibly areas of collagen degeneration
 
*Microscopically: acanthosis, spongiosis, erosions or ulceration, predominantly eosinophilic dermatitis, possibly areas of collagen degeneration
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===Eosinophilic granulomas===
 
===Eosinophilic granulomas===
 
*Involves cats, dogs, horses
 
*Involves cats, dogs, horses
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**Nodular dermatitis or stomatitis
 
**Nodular dermatitis or stomatitis
 
**Fragments of degenerated collagen surrounded by eosinophils and macrophages
 
**Fragments of degenerated collagen surrounded by eosinophils and macrophages
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===Eosinophilic folliculitis and furunculosis===
 
===Eosinophilic folliculitis and furunculosis===
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*Possibly due to arthropod bites
 
*Possibly due to arthropod bites
 
*May be multifocal in horses
 
*May be multifocal in horses
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==Sterile granulomatous disorders==
 
==Sterile granulomatous disorders==
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*Grossly: pustular and nodular dermatitis with oedema involving the face, ears, mucocutaneous junctions
 
*Grossly: pustular and nodular dermatitis with oedema involving the face, ears, mucocutaneous junctions
 
*Microscopically: granulomatous or pyogranulomatous perifolliculitis, paniculitis and dermatitis
 
*Microscopically: granulomatous or pyogranulomatous perifolliculitis, paniculitis and dermatitis
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===Equine generalised granulomatous disease===
 
===Equine generalised granulomatous disease===
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*Grossly: alopecia, scales, crusts, sometimes nodules and masses
 
*Grossly: alopecia, scales, crusts, sometimes nodules and masses
 
*Microscopically: multifocal granulomas, multinucleated giant cells
 
*Microscopically: multifocal granulomas, multinucleated giant cells
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[[Category:Integumentary System - Pathology]]

Revision as of 18:23, 22 February 2011

Seborrhea



Sebaceous adenitis

  • Epidermal growth or differentiation disorder
  • 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. discoid lupus erythematosus


Hyperpigmentation

Image of endocrine hyperpigmentation from Cornell Veterinary Medicine

  • Results from irritation or inflammation, pigmented neoplasms or 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