Difference between revisions of "Skin Other - Pathology"
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==Sterile granulomatous disorders== | ==Sterile granulomatous disorders== | ||
| + | |||
===Juvenile pyoderma=== | ===Juvenile pyoderma=== | ||
*Also known as '''Juvenile sterile granulomatous dermatitis and lymphadenitis, juveline cellulitis, puppy strangles''' | *Also known as '''Juvenile sterile granulomatous dermatitis and lymphadenitis, juveline cellulitis, puppy strangles''' | ||
| Line 92: | Line 93: | ||
===Equine generalised granulomatous disease=== | ===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 12:41, 31 October 2008
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This article is still under construction. |
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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 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