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Pet Owner Educational Atlas

Dermatology Reviewer: Carmen Lorente


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Table of Contents Anatomy of the skin and hair 1 2 3 4

Healthy skin cross-section Hair follicle structure Skin barrier Characteristics of the claw. Trimming technique

Physiopathology of the skin and hair 5 6 7 8 9 10 11 12

Secondary intention healing phases Good versus bad healing Primary lesions Lesions that can be primary and secondary Secondary lesions Disorders of the hair follicle Types of alopecia: inflammatory and non-inflammatory Pruritus characteristics

Medical and surgical treatments 13 14 15 16 17

Types of wounds Types of burns Dressings. Wet healing Procedures to avoid tension on the skin (I). Relaxing incisions Procedures to avoid tension on the skin (II). Suture patterns

Skin pathologies Parasites 18 19 20 21 22 23 24

FAD. Flea allergy dermatitis Tick bites and attachment to the skin Types of scabies (I): Sarcoptes and Notoedres Types of scabies (II): Otodectes and Cheyletiella Types of scabies (III): Demodex Mosquito bites and disease transmission Myiasis larvae


Pet Owner Educational Atlas. Dermatology

Fungi and yeast 25 26 27

Dermatophytosis: Microsporum, Trichophyton and Epidermophyton Cutaneous mycosis Dermatitis caused by Malasseziaw

Infections 28 29 30 31 32 33 34

Pyotraumatic dermatitis, acute moist dermatitis or hot spot Superficial and deep pyoderma Mucocutaneous pyoderma and epitheliotropic lymphoma Sebaceous adenitis Infectious and sterile panniculitis Skin folds (I). Lip fold dermatitis and resolution Skin folds (II). Tail fold dermatitis and resolution

Eyes and ears 35 36 37 38 39 40

Entropion and resolution Ectropion and resolution Healthy ear. Correct cleaning and washing technique External otitis. Ear exudates smears Otitis media and interna Otohaematoma. Types of resolution

Neoplasms 41 42 43 44 45

Nodules. Inflammatory or neoplastic process? Fibrosarcoma and resolution Mastocytoma and metastasis Squamous cell carcinoma Mammary tumour

Miscellany 46 47 48 49 50 51 52 53 54

Frequent disorders of the pads Interdigital fistula caused by a foreign body (spikelet) Pathologies of the anal sacs Dental fistula Foliaceous pemphigus. Autoimmune mechanism Allergies and atopies Anaphylactic reaction. Angioedema Endocrine diseases Seborrheic keratoses disorders

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Anatomy of the skin and hair

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Healthy skin cross-section STRATA: Corneum Granulosum Spinosum Basale

Superficial

Epidermis

Nerve endings

Apocrine gland Hair follicle

Deep

Subcutaneous tissue

Nerve

Cutaneous muscle Artery Vein

Panniculus adipose tissue

Arteriovenous plexus

Middle

Dermis

Sebaceous gland


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Physiopathology of the skin and hair

5 Secondary intention

healing phases 2 Proliferative phase

1 Inflammatory phase

Haemorrhage

Suppuration (pus) Fibrin clot

Neutrophil diapedesis

Arrival of fibroblasts that synthesize collagen

Platelets aggregate Initial vasoconstriction (5-10 minutes)

Phagocytosis cell migration

Posterior vasodilatation and increase of the vascular permeability

Interstitial oedema

3 Remodelling phase

Proliferation of endothelial cells

Granulation tissue formation

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Epithelialization phase

New epidermis

Collagen synthesis and deposit

Migration of epithelial cells over the granulation tissue

Resorption of old collagen Vascular neoformation

Remodelling and contraction of the wound

Connective tissue formation

Bacteria

Erythrocytes

Macrophages

Platelets

Eosinophils

Neutrophils

Fibroblasts


Physiopathology of the skin and hair

7 Primary lesions

Macule Change in colour of the epidermis without altering elevation, consistency or thickness. It may be erythematous and hyper or hypopigmented

Papule Small elevated lesion, erythematous and slightly hardened of up to 1 cm in length caused by cellular infiltration or proliferation

Plaque Elevated lesion, flat, solid and wide of more than 1 cm in length associated to cellular infiltration or proliferation

Pustule Small circumscribed cutaneous elevation that contains purulent material. It may be intraepidermal, subepidermal and follicular

Vesicle Small circumscribed elevation with a collection of clear fluid within the epidermis or below it. It can be intraepidermal or subepidermal

Nodule Solid lesion over 1 cm in diameter, dermal location and usually extended into the deep layers of the skin. It may be of inflammatory or neoplastic origin

Tumour Large mass that can affect any skin structure. It may be of inflammatory or neoplastic origin

Cyst Cavity delimited by an epithelium, which is clinically presented as a nodule or tumour. Desquamative materials or glandular secretions are stored in its interior

Skin wheal Oedematous cutaneous area, raised and irregular that often changes size and shape

Wart Solid elevation of the epidermis with a formation of exophytic projections and generally covered by a scab

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Medical and surgical treatments

15 Dressings. Wet healing Wet secondary intention healing of wounds with dressings 1 Clean the lesion and disinfect the area

2 Shave the hair of surrounding areas

3 Wash the wound thoroughly with saline solution

4 Surgically debride of the wound

exhaustively

under pressure. Remove detritus or contaminating particles

and its edges

5 Apply a bandage with dressings that promote the correct formation of granulation tissue. Monitor the healing

Layers of the dressing Tertiary or retaining layer Secondary or absorbent layer

Wound

Primary or contact layer


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Skin pathologies

20 Tick bites and

attachment to the skin Female tick ingesting blood in order to lay the eggs

Tick ​​head (retractable sucking mouthparts) The tick secretes a substance that attachs its mouthparts into the host’s skin

Palps Chelicerae

Inflammatory skin reaction

Hypostome

The saliva of the tick has an anticoagulant effect and causes a small haemorrhage from which it feeds

The tick inoculates the pathogenic agents during feeding


Skin pathologies

35 Entropion and resolution

Lesions in the cornea of the eye

The edge of the eyelid is folded and is in contact with the cornea

Surgical resolution techniques HOTZ-CELSUS TECHNIQUE Solves the entropion of the lower eyelid

MODIFIED HOTZCELSUS TECHNIQUE: ARROWHEAD Solves the entropion of the lateral edge of the eyelid

FRANS STADES TECHNIQUE Solves the entropion of the upper eyelid

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Skin pathologies

42 Fibrosarcoma

and resolution Surgical removal with wide safety margins Nodule on the withers

Fibrosarcoma is a malignant neoplasm that may appear as a nodule in the skin. Its surgical resolution can be accompanied by radiation therapy

Lateral safety margins

When removing a malignant neoplasm (highly invasive) security surgical margins should be established. As a result, the resulting wound is larger than the tumour but this procedure also reduces the likelihood of recurrence or metastasis

Infiltrative digitations of the neoplasm

Safety margins in depth


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Skin pathologies

47 Interdigital fistula caused

by a foreign body (spikelet) Deep penetration of the spikelet

Location of the spikelet

Course of the fistula

Interdigital inflammation

Spikelet entry point

The veterinary surgeon introduces alligator forceps by the fistulous trajectory to access the spikelet. Sometimes surgery is needed to remove the foreign body and close the fistula


This illustrated work aims at helping veterinary surgeons to communicate with pet owners. In keeping with the previous volume about surgery, the illustrations of this atlas dedicated to dermatology will simplify the explanations given by vets to their clients about the anatomical, physiological and pathological characteristics of skin, as well as those about the diagnostic tests, treatments and surgical techniques that may need to be carried out in some cases. Every illustration was designed to help in the different clinical aspects of the dermatology consultation, from the anatomical and physiological considerations about the skin and its annexes, to the graphic description of infectious, inflammatory, endocrine, allergic or tumoral disease processes which cause dermatological conditions. The clarity and accuracy of the illustrations, designed to make the explanations given to owners easier to understand and less time-consuming, turn this atlas into another useful clinical tool.


Pet owner educational atlas dermatology