Difference between revisions of "Skin Other - Pathology"

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#REDIRECT[[:Category:Integumentary System - Pathology]]
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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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==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.'' [[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 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

Revision as of 15:12, 21 February 2011

 This article has been peer reviewed but is awaiting expert review. If you would like to help with this, please see more information about expert reviewing.


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()Map INTEGUMENTARY SYSTEM (Map)



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 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. ectoparasites, fungal infections, 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. 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
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