Difference between revisions of "Skin Immunologic - Pathology"

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#REDIRECT[[:Category:Integumentary System - Immunologic Pathology]]
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|backcolour = FFCCCC
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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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|pagetype =Pathology
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<br>
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==General==
 +
 
 +
*Classification:
 +
**Hypersensitivity - response to normally harmless substances
 +
**Auto-immune - antobodies or T-cells reactive against self-antigens
 +
*Mostly involves mixture of types described below
 +
 
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===Type I reactions===
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 +
 
 +
===Type II reactions===
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 +
 
 +
===Type III reactions===
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 +
 
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===Type IV reactions===
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==Hypersensitivity reactions==
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===[[Allergic Contact Dermatitis]]===
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 +
 
 +
 
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===Atopy===
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*Involves [[Type I Hypersensitivity|Type I reaction]]
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*Mainly causes pruritus
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*Dogs - face rubbing and foot licking; secondary [[Bacterial skin infections - Pathology#Pyoderma|pyoderma]] or [[Skin Other - Pathology#Secondary seborrhea|seborrhea]]
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*Cats - facial, ear or generalised pruritus, miliary dermatitis, [[Skin Other - Pathology#Eosinophilic granuloma|eosinophilic granuloma complex]], symmetric alopecia
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*Horses - pruritic hea, pinnae, ventrum, legs, tailhead or recurrent [[Skin Glossary - Pathology|urticaria]]
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*Lesions generally due to self-trauma
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*Microscopically:
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**Hyperplastic superficial perivascular dermatitis
 +
**Mast cells, eosinophils, nonmetachromatic mononuclear cells
 +
**Perivascular inflammation may be involved especially in horses
 +
 
 +
 
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[[Category:Type I Hypersensitivity Diseases]]
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[[Category:Integumentary System - Hypersensitivity Reactions]]
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===[[Culicoides Hypersensitivity]]===
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===[[Flea Bite Hypersensitivity]]===
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==Autoimmune reactions==
 +
 
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===Bullous pemphigoid===
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*Dogs and horses
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*Involves oral cavity, mucocutaneous junctions, groin and axilla
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*Subepidermal vesicles and bullae
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*Antibodies bound to basement membrane
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*Grossly:
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**Similar to [[Skin Immunologic - Pathology#Pemphigus|Pemphigus vulgaris]]
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*Microscopically:
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**Bullae containing fibrin, [[Neutrophils|neutrophils]] or [[Eosinophils|eosinophils]]
 +
**Basement membrane forms floor of bullae and roof is lined with basal cells
 +
*Bullae may rupture -> ulcers
 +
 
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===Dermatomyositis===
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*See also [[Muscles Developmental - Pathology#Canine dermatomyositis|Canine dermatomyositis]]
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*Affects puppies of collies and shetland sheepdogs from 8 weeks of age
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*Lesions - vesiculating dermatitis
 +
**Face, lips, external ears, later distal extremities
 +
*Microscopically: interface dermatitis and basal cell degeneration of epidermis and follicular wall, atrophy of follicles, epidermal vesicles and pustules, dermal scarring
 +
 
 +
===Lupus erythematosus===
 +
 
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*'''Systemic (SLE)'''
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**Multiple organs involved
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**Cats, dogs, horses
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**Immune dysregulation:
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***Damaged T-cell suppressor function, either primary deficiency or antibody mediated
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***Cytokine dysregulation
 +
***Resulting B-cell hyperactivity -> antibodies to self antigens -> antigen-antibody complexes deposited in various tissues -> Type III hypersensitivity
 +
**Lesions localised or generalised
 +
**Erythema, alopecia, depigmentation, crusting and scaling, ulceration
 +
**Microscopically: lymphohistiocytic interface dermatitis, thickened basement membrane, vasculitis, subepidermal vesicles, basal cell degeneration
 +
*'''Discoid'''
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**Milder variant of systemic
 +
**Depigmentation, erythema, scaling, erosions, ulceration, crusting
 +
**Usually involves nasal planum, dorsum of muzzle, occasionally pinnae, lips, oral mucosa or periocular area
 +
**Microscopically: lichenoid interface dermatitis, often with lymphocytes, plasma cells, basal cell degeneration, loss of pigment
 +
 
 +
===[[Pemphigus]]===

Revision as of 16:32, 22 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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General

  • Classification:
    • Hypersensitivity - response to normally harmless substances
    • Auto-immune - antobodies or T-cells reactive against self-antigens
  • Mostly involves mixture of types described below

Type I reactions

Type II reactions

Type III reactions

Type IV reactions

Hypersensitivity reactions

Allergic Contact Dermatitis

Atopy

  • Involves Type I reaction
  • Mainly causes pruritus
  • Dogs - face rubbing and foot licking; secondary pyoderma or seborrhea
  • Cats - facial, ear or generalised pruritus, miliary dermatitis, eosinophilic granuloma complex, symmetric alopecia
  • Horses - pruritic hea, pinnae, ventrum, legs, tailhead or recurrent urticaria
  • Lesions generally due to self-trauma
  • Microscopically:
    • Hyperplastic superficial perivascular dermatitis
    • Mast cells, eosinophils, nonmetachromatic mononuclear cells
    • Perivascular inflammation may be involved especially in horses


Culicoides Hypersensitivity

Flea Bite Hypersensitivity

Autoimmune reactions

Bullous pemphigoid

  • Dogs and horses
  • Involves oral cavity, mucocutaneous junctions, groin and axilla
  • Subepidermal vesicles and bullae
  • Antibodies bound to basement membrane
  • Grossly:
  • Microscopically:
    • Bullae containing fibrin, neutrophils or eosinophils
    • Basement membrane forms floor of bullae and roof is lined with basal cells
  • Bullae may rupture -> ulcers

Dermatomyositis

  • See also Canine dermatomyositis
  • Affects puppies of collies and shetland sheepdogs from 8 weeks of age
  • Lesions - vesiculating dermatitis
    • Face, lips, external ears, later distal extremities
  • Microscopically: interface dermatitis and basal cell degeneration of epidermis and follicular wall, atrophy of follicles, epidermal vesicles and pustules, dermal scarring

Lupus erythematosus

  • Systemic (SLE)
    • Multiple organs involved
    • Cats, dogs, horses
    • Immune dysregulation:
      • Damaged T-cell suppressor function, either primary deficiency or antibody mediated
      • Cytokine dysregulation
      • Resulting B-cell hyperactivity -> antibodies to self antigens -> antigen-antibody complexes deposited in various tissues -> Type III hypersensitivity
    • Lesions localised or generalised
    • Erythema, alopecia, depigmentation, crusting and scaling, ulceration
    • Microscopically: lymphohistiocytic interface dermatitis, thickened basement membrane, vasculitis, subepidermal vesicles, basal cell degeneration
  • Discoid
    • Milder variant of systemic
    • Depigmentation, erythema, scaling, erosions, ulceration, crusting
    • Usually involves nasal planum, dorsum of muzzle, occasionally pinnae, lips, oral mucosa or periocular area
    • Microscopically: lichenoid interface dermatitis, often with lymphocytes, plasma cells, basal cell degeneration, loss of pigment

Pemphigus

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