Difference between revisions of "Skin Other - Pathology"
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*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 | ||
===Eosinophilic granulomas=== | ===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=== | ===Eosinophilic folliculitis and furunculosis=== | ||
Revision as of 12:29, 31 October 2008
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