L3 - Morphology Of Skin Lesions PDF

Integumentary system: Lecture 1 Contents ❑ General Functions VETERINARY PATHOLOGY II ❑ SYSTEMIC VPM 3419: ❑ Normal structure INTEGUMENTARY ❑ Dermatohistopathology SYSTEM - Epidermal changes - Dermal changes - Subcutaneous cha...

Integumentary system: Lecture 1 Contents ❑ General Functions VETERINARY PATHOLOGY II ❑ SYSTEMIC VPM 3419: ❑ Normal structure INTEGUMENTARY ❑ Dermatohistopathology SYSTEM - Epidermal changes - Dermal changes - Subcutaneous changes VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II Integumentary system: Lecture 2 Contents Morphology of skin lesions ❑ 1. Primary skin lesions ❑ 2. Secondary skin lesions VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  Integumentary system: Lecture 2 ❑ 1. Primary skin lesions: Develop as direct result of disease process Occur spontaneously by itself ❑ 2. Secondary skin lesions Evolve from 1° lesions. Occur due to patient’s activities. ➔ Some lesions might be 1° or 2°: - Popped acne - Alopecia in: hypothyroidism (1°) vs. flea allergy dermatitis (2°) VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II Integumentary system: Lecture 2 VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  Integumentary system: Lecture 2 ❑ 1. Primary skin lesions: 1) Macule / Patch 2) Papule / Plaque 3) Nodule 4) Tumor 5) Pustule 6) Wheal 7) Vesicle / Bulla 8) Alopecia VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  Integumentary system: Lecture 2 ❑ 2. Secondary skin lesions: 1) Scale 9) Hyperpigmentation 2) Epidermal collarette 10) Fissure 3) Crust 11) Callus 4) Scar 5) Erosion 6) Ulceration 7) Excoriation 8) Lichenification VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  1. Primary skin lesions ❑ Macule / Patch: a circumscribed, flat spot characterized by change in colour of the skin. A large macule, > 1 cm in diameter is called a patch. Discolouration can be due to increase in melanin pigmentation, depigmentation and erythema (eg. allergies, hyperadrenocorticism, sertoli cell tumor, hypothyroidism). *Erythema:superficial redness in patches due to dilated capillaries @ hyperaemia VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  1. Primary skin lesions Lentigo/lentigines: a benign heritable condition of hyperpigmention; due to focal increase in number of melanocytes VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  1. Primary skin lesions ❑ Papule / Plaque: a small, solid elevation of the skin up to 1 cm in diameter. A larger, flat-topped elevation is called a plaque. Palpated as a solid mass. Produced by infiltration of inflammatory cells, epidermal hypertrophy or intraepidermal and subepidermal edema (eg. early stage of acne, allergic dermatitis, scabies, candidiasis, dermatomycosis). VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II 1. Primary skin lesions ❑ Papules and plaques on the trunk of a dog that developed a hypersensitivity reaction to a shampoo VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  1. Primary skin lesions ❑ Nodule: a small, circumscribed, solid elevation that usually extends into the deeper layers of the skin. It may be inflammatory or neoplastic (eg. leprosy, papillomatoses, acral lick dermatitis). VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  1. Primary skin lesions Lumpy skin disease (pox Many infectious agents and virus) several immunologic conditions can cause nodular dermatitis in horses VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  1. Primary skin lesions ❑ Tumor: a neoplastic enlargement of large size that may be composed of any structure of the skin or subcutaneous tissue (eg. fibroma, lipoma, melanoma, carcinomas). - Excessive uncoordinated growth from normal tissue - usually persists in same excessive manner after cessation of stimuli which invoked the change VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II 1. Primary skin lesions ❑ Eg. Cutaneous epitheliotropic lymphoma in a dog VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  1. Primary skin lesions ❑ Pustule: a small circumscribed elevation of skin filled with pus (eg. acne, demodicosis, dermatomycosis, pyoderma, pemphigus foliaceus). VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  1. Primary skin lesions Udder pyoderma (pustules) Dog with pemphigus foliaceus (pustules) VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  1. Primary skin lesions ❑ Wheal: a sharply circumscribed, raised lesion consisting of edema (eg. urticaria, allergic dermatitis, flea or insect bites). VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  1. Primary skin lesions Wheals are most commonly seen with hypersensitivity (allergic) disorders in horses and less frequently with dogs. VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  1. Primary skin lesions ❑ Vesicle / Bulla: a sharply circumscribed elevation of the skin filled with clear, free fluid and up to 1 cm in diameter. A large vesicle lesion is called a bulla. Also known as blister. (eg. allergic contact dermatitis, dermatomycosis). VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  1. Primary skin lesions Contact irritant dermatitis (vesicle) Vesicular exanthema (bulla) VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  1. Primary skin lesions ❑ Alopecia: partial or complete lack of hairs in areas where they are normally present. Distribution: diffuse, regional, multifocal or focal. Many factors: hormonal, nutritional, autoimmune, stress, parasitic, bacterial, allergy, trauma. (eg. Hypothyroidism, hyperadrenocorticism, mange, pemphigus, allergy dermatitis, psychogenic alopecia). VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  2. Secondary skin lesions ❑ Scale: flaking off of stratum corneum or an accumulation of loose fragments of the horny layer of the skin; final product of epidermal keratinization. (eg. allergic dermatitis, endocrine disorders, dry skin, seborrhea & demodicosis). dandruff VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  2. Secondary skin lesions sunburn peeling chronic seborrheic dermatitis VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  2. Secondary skin lesions ❑ Epidermal collarette: Circular lesion with circular rim of scale and or a peeling edge. Often with border of redness and central area of hair loss. Associated with vesicular or pustular lesion. (eg. Canine pyoderma, insect bite, fungal infection). VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  2. Secondary skin lesions ❑ Crust: a dry exudate on the surface of a lesion; dried exudate, serum, pus, blood, scales or medications adhere to the surface and often mingle with hair (eg. demodicosis, dermatomycosis, solar dermatitis, scabies, pyodermas). VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II 2. Secondary skin lesions ❑ Crust E.g. idiopathic photosensitization VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  2. Secondary skin lesions ❑ Scar: an area of fibrous tissue that has replaced the damaged dermis or subcutaneous tissue. Usually depigmented and hairless. (eg. deep pyodermas, deep wounds and abrasions, thermal & chemical burn). VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  2. Secondary skin lesions ❑ Scar VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  2. Secondary skin lesions ❑ Erosion: denuded epithelium with basement membrane intact and hair follicles preserved. Healing occurs with no scar. (eg. Impetigo, pemphigus, burns, consequence of ruptured pustules, vesicles or bulla). VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  2. Secondary skin lesions ❑ Ulcer: a break in the continuity of the epidermis with exposure of the underlying dermis and destroys hair follicles. Scar usually develop after healing. (eg. SCC, burns, basal cell epithelioma, pyoderma, pemphigus, severe autoimmune disease). VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II 2. Secondary skin lesions ❑ Ulcer VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  2. Secondary skin lesions ❑ Excoriation: a superficial removal of epidermis caused by scratching, biting or rubbing @ self- inflicted (eg. scabies, allergic dermatitis, acute moist dermatitis). VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II 2. Secondary skin lesions ❑ Excoriation VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  2. Secondary skin lesions ❑ Lichenification: a thickening and hardening (leather) of the skin characterized by an exaggeration of the superficial skin markings (elephant skin-like appearance). (eg. Chronic inflammation, persistent friction, acanthosis nigricans, allergic dermatitis, ovarian imbalance, Malassezia infection). VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  2. Secondary skin lesions ❑ Lichenification and alopecia in a bovine with sarcoptic mange. Elephant skin VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  2. Secondary skin lesions ❑ Hyperpigmentation: an excessive colouration of the skin caused by increase deposition of melanin (eg. Ovarian imbalance, scabies, dermatomycosis, demodicosis, hypothyroidism). VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II 2. Secondary skin lesions ❑ Hyperpigmentation: VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  2. Secondary skin lesions ❑ Hyperkeratosis: increase in thickness of the horny layer of the skin (eg. acanthosis nigricans, male feminizing syndrome, canine distemper, dermatophytosis). VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  2. Secondary skin lesions ❑ Hyperkeratosis: VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  2. Secondary skin lesions ❑ Fissure: a linear cleavage (crack or split) into the epidermis, or through the epidermis into the underlying dermis caused by disease or injury. (eg. Dogs with hepatocutaneous syndrome, footpad hyperkeratosis- lameness, excessive drying of skin). VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  2. Secondary skin lesions Cracked heels Fissure: eg. nasodigital hyperkeratosis, an idiopathic disorder seen in old dogs. VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  2. Secondary skin lesions ❑ Callus: thick, firm, hyperkeratotic, hairless plaque with increased skin folds, wrinkles or fissures developed following repeated friction, pressure, irritation. (eg. Trauma over body prominence such as elbow, sternum or side of digit). VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II  SUMMARY PRIMARY SECONDARY VPM 3419: SYSTEMIC VETERINARY PATHOLOGY II Circulatory disturbances VPM 3417: VETERINARY PATHOLOGY III