Difference between revisions of "Skin Environmental - Pathology"

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#REDIRECT[[:Category:Integumentary System - Environmental Pathology]]
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==Chemical damage==
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===[[Contact Dermatitis]]===
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===[[Ergot Poisoning]]===
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===[[Fescue Poisoning]]===
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===[[Selenium Poisoning]]===
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==Physical damage==
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===[[Acral Lick Dermatitis]]===
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===[[Callus]]===
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===[[Feline Psychogenic Alopecia]]===
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===[[Injection Site Reaction]]===
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===[[Intertrigo]]===
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===[[Pyotraumatic Dermatitis]]===
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===[[Radiation Damage]]===
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===[[Low Temperature Damage]]===
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===High temperature damage===
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*May result from excessive heat, liquids, flames, friction, lightning, electricity
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*Partial or full thickness burns (first, second and third degree burns)
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*Full thickness burns:
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**Total destruction of skin and adnexa
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**Has to be repaired by grafting
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**Life threatening
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*Partial thickness burns:
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**Some structures preserved -> regeneration may occur
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**Grossly:
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***Erythema (capillary dilation)
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***Oedema (increased permeability of capillaries)
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***Vesicles
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**Microscopically:
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***[[Necrosis - Pathology#Coagulation Necrosis|Coagulation necrosis]] of epidermis
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***Subepidermal vesiculation
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***Necrosis of adnexa
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***Degenerated subepidermal collagen
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***May involve large numbers of [[Neutrophils|neutrophils]] if secondary ifection is present
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 +
 
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[[Category:Integumentary System - Physical Damage]]
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==Sunlight damage==
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*Transient erythema may develop into sunburn erythema (warmth, swelling, pain)
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*Diffusion of inflammatory mediators (''e.g.'' cytokines) from damaged keratinocytes and endothelial cells
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*Photooxidation of existing melanin -> pigment darkening
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*Melanogenesis
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*Immune responses of skin are reduced by UV light
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 +
 
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[[Category:Integumentary System - Sunlight Damage]]
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 +
 
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===Solar dermatosis and neoplasia===
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*Caused by chronic sunlight damage
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*Damaged tissue generates free radicals than may damage nucleis acids and proteins
 +
*If damage repaired prior to mitosis - no lasting effect
 +
*If mitosis occurs before repair, post-mitotic repair is prone to faults and DNA mutations may result in neoplasia
 +
 
 +
 
 +
[[Category:Integumentary System - Sunlight Damage]]
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 +
 
 +
===Solar dermatitis===
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*Particularly in white animals and where little or no hair is present
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*Grossly:
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**[[Skin Glossary - Pathology|Erythema, scaling and crusting]]
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**-> Wrinkled nand thickened skin
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** Squamous cell carcinoma or haemangiosarcoma/haemangioma may develop
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*Microscopically:
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**Dyskeratotic cells
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**Intercellular oedema
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**Vacuolated keratinocytes
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**Followed by [[Skin Glossary - Pathology|hyperkeratosis, parakeratosis and acanthosis]]
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**Endothelial swelling
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**Haemorrhage
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**Hyperplasia
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**Dermal fibrosis
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**Dogs may develop actinic [[Skin Glossary - Pathology|comedones]]
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[[Category:Integumentary System - Sunlight Damage]]
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===[[Photosensitisation]]===
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===Photoenhanced dermatoses===
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*Many [[Skin Immunologic - Pathology|immune-mediated]] cutaneous disease are made worse by sunlight
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**Lupus erythematosus
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**Dermatomyositis
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**Pemphigus erythematosus
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*Vasculitis in extremities, especially white-haired horses
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*Grossly:
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**Erythematous, well circumscribed crusted lesions or hyperkeratotic [[Skin Glossary - Pathology|plaques]]
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*Microscopically:
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**Vasculitis of superficial dermal vessels
 +
**Thrombi may be seen
 +
 
 +
[[Category:Integumentary System - Sunlight Damage]]

Revision as of 16:10, 21 February 2011

Chemical damage

Contact Dermatitis

Ergot Poisoning

Fescue Poisoning

Selenium Poisoning

Physical damage

Acral Lick Dermatitis

Callus

Feline Psychogenic Alopecia

Injection Site Reaction

Intertrigo

Pyotraumatic Dermatitis

Radiation Damage

Low Temperature Damage

High temperature damage

  • May result from excessive heat, liquids, flames, friction, lightning, electricity
  • Partial or full thickness burns (first, second and third degree burns)
  • Full thickness burns:
    • Total destruction of skin and adnexa
    • Has to be repaired by grafting
    • Life threatening
  • Partial thickness burns:
    • Some structures preserved -> regeneration may occur
    • Grossly:
      • Erythema (capillary dilation)
      • Oedema (increased permeability of capillaries)
      • Vesicles
    • Microscopically:
      • Coagulation necrosis of epidermis
      • Subepidermal vesiculation
      • Necrosis of adnexa
      • Degenerated subepidermal collagen
      • May involve large numbers of neutrophils if secondary ifection is present

Sunlight damage

  • Transient erythema may develop into sunburn erythema (warmth, swelling, pain)
  • Diffusion of inflammatory mediators (e.g. cytokines) from damaged keratinocytes and endothelial cells
  • Photooxidation of existing melanin -> pigment darkening
  • Melanogenesis
  • Immune responses of skin are reduced by UV light


Solar dermatosis and neoplasia

  • Caused by chronic sunlight damage
  • Damaged tissue generates free radicals than may damage nucleis acids and proteins
  • If damage repaired prior to mitosis - no lasting effect
  • If mitosis occurs before repair, post-mitotic repair is prone to faults and DNA mutations may result in neoplasia


Solar dermatitis

  • Particularly in white animals and where little or no hair is present
  • Grossly:
  • Microscopically:

Photosensitisation

Photoenhanced dermatoses

  • Many immune-mediated cutaneous disease are made worse by sunlight
    • Lupus erythematosus
    • Dermatomyositis
    • Pemphigus erythematosus
  • Vasculitis in extremities, especially white-haired horses
  • Grossly:
    • Erythematous, well circumscribed crusted lesions or hyperkeratotic plaques
  • Microscopically:
    • Vasculitis of superficial dermal vessels
    • Thrombi may be seen
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