Practical Equine Dermatology

Janet D. Littlewood, David H. Lloyd, J. Mark Craig

• Publisher: Wiley-Blackwell
• Year: 2021
• Print ISBN: 9781119765486
• eBook ISBN: 9781119765509
• Edition: 2
• Topic: Medicine
• Subtopic: Equine Veterinary Science

A practical and comprehensive reference for equine dermatology cases

The newly revised Second Edition of Practical Equine Dermatology delivers a thorough exploration of common dermatological conditions affecting horses whilst also drawing attention to rarer conditions.

The book offers detailed advice on treatments and products currently available on the veterinary market in a problem-oriented layout that provides a practical approach to quick and efficient diagnosis. Clinical presentations, diagnostic features, and disorder management for each described condition are presented in an easy-to-digest bullet-point format supported by concise references and recommendations for further reading.

An ideal quick reference for veterinary practitioners on the key points of equine skin conditions, this new edition also includes:

• A thorough introduction to the diagnostic approach, including taking an accurate history, the clinical examination, and diagnostic tests.
• Comprehensive exploration of pruritus, including contagious conditions, such as ectoparasites and helminth infestation, and non-contagious conditions, such as insect attack and atopic dermatitis.
• Practical discussion of crusting and scaling, including primary seborrhoea and infectious causes, such as superficial fungal infections and environmental factors.
• In-depth examination of ulcers and erosions, nodules and swellings, coat problems, and pigmentary disorders.

Perfect for any practising veterinarian seeing equine cases in first opinion practice, Practical Equine Dermatology will also be of use to veterinary students with an interest in equine veterinary medicine.

1
The diagnostic approach

A structured approach is essential. Vital information is obtained during the history‐taking process and sufficient time must be allowed for this. Accurate information on husbandry is particularly important. Clinical examination must include systemic and skin components. The process is illustrated with flow diagrams (Figures 1.1 and 1.2).

TAKING THE HISTORY

The approach (Figure 1.1) is similar to that adopted in other species.Points to include are:

• Breed, age, sex, origin:
  • Consider these aspects carefully; in many conditions, these simple data will have an important impact on your diagnostic considerations.
• History of skin problems in related animals.
• Type of husbandry and use:
  • Length of time owned.
  • Use – competitions, general riding, breeding, racing.
  • Feeding regimen.
  • Periods spent in stable or at pasture.
  • Type of stable and bedding – stable hygiene, contamination.
  • Conditions in paddocks – mature meadow pasture or new grass ley, proximity of water, trees.
  • Seasonal changes in management.
  • Routine health care procedures – vaccination, deworming.

    

    Figure 1.1 Taking the history. Components and the sequence of the history taking process. Analysis of the history should enable the clinician to construct an initial list of differential diagnoses that may help to focus the clinical examination along particular diagnostic lines. It may enable the diagnostic process to be abbreviated where a likely diagnosis is indicated, or it may point towards the need for a more detailed approach.

  • Grooming procedures – sharing of grooming kit, tack, grooms.
  • Equipment used in contact with horse – boots, bandages, saddle cloths, rugs.
  • Contact with other horses, other species – opportunities for disease transmission.
  • History of the current problem.
    • First signs, progression, response to treatment and management changes.
    • Seasonal effects.
    • Previous episodes of disease.
    • Results of any diagnostic tests.
    • Current or recent therapy – includes questions about use of over‐the‐counter and non‐veterinary products.
    • Evidence of transmission – lesions in other horses, other species, humans.
  • General health – concurrent or previous conditions.

Figure 1.2 Clinical examination and diagnostic procedures. A thorough general and dermatological examination should be carried out unless the history points clearly towards a diagnosis. Examination coupled with history enable a list of differential diagnoses to be drawn up, formulation of a diagnostic plan and the selection of appropriate tests and sites to be sampled, and/or therapeutic trials.

CLINICAL EXAMINATION

A full clinical examination to assess both the general health status and the skin is necessary in most cases. Ensure that the animal is adequately restrained and that you have sufficient light. Work systematically down each body region, beginning at the head and ending at the tail and perineal region. Be sure to include all aspects of the feet including the coronary band and the frog. The skin may need to be cleaned to observe some lesions. In some instances, sedation may be necessary.

A record of the distribution and severity of primary and secondary lesions should be kept. Forms including a horse outline make this much easier (Figure 1.3).

It may be helpful to visit and examine the paddocks and exercise areas used.

Figure 1.3 Example of an examination form for recording distribution and nature of lesions in equine dermatology cases.

DIAGNOSTIC TESTS

The history and clinical examination should enable you to formulate a list of differential diagnoses. It may help to create a problem list, identifying the relevant historical features and predominant clinical signs, categorising them as contagious or non‐contagious, and allocating the disease within the following groups, which form the basis for the problem‐orientated approach in this book:

• Pruritic
• Crusting and scaling
• Ulcerative and erosive
• Nodular or swollen
• Alopecia/hair coat changes
• Pigmentary disorders

A diagnostic plan can then be constructed, diagnostic procedures selected, and samples collected. Sample collection may include the following techniques.

Hair plucks

Useful to determine whether the lesions of alopecia or hypotrichosis are due to self‐inflicted damage (fractured hair shafts, split ends) indicating that the condition is pruritic, or due to abnormal hair growth (absence of anagen roots, abnormal catagen roots), and to examine for dermatophytes and for parasite eggs.

• Choose fresh, unmedicated lesions.
• For suspected dermatophytosis, where cultures are required, first lightly clean the areas to be sampled with 70% alcohol (to r...

Table of contents

• Cover
• Table of Contents
• Title Page
• Copyright Page
• Preface to the second edition
• Acknowledgements
• Disclaimer
• 1 The diagnostic approach
• 2 Pruritus
• 3 Crusting and Scaling
• 4 Ulcers and Erosions
• 5 Papules, Nodules, and Masses
• 6 Coat Problems
• 7 Pigmentary Disorders
• 8 Therapy in Equine Dermatology
• Index
• End User License Agreement