This page intentionally left blank Blackwell’s Five-Minute Veterinary Consult Clinical Companion Small Animal Dermatology Second Edition This page intentionally left blank Blackwell’s Five-Minute Veterinary Consult Clinical Companion Small Animal Dermatology Second Edition Karen Helton Rhodes, DVM Diplomate, American College of Veterinary Dermatology Riverdale Veterinary Dermatology Riverdale, New Jersey and Alexander H. Werner, VMD Diplomate, American College of Veterinary Dermatology Animal Dermatology Center Studio City, California A John Wiley & Sons, Inc., Publication This edition fi rst published 2011 © 2011 by Blackwell Publishing Ltd. Blackwell Publishing was acquired by John Wiley & Sons in February 2007. Blackwell’s publishing program has been merged with Wiley’s global Scientifi c, Technical and Medical business to form Wiley-Blackwell. 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Other title: Five-minute veterinary consult clinical companion Other title: Small animal dermatology Rev. ed. of: The fi ve minute veterinary consult clinical companion : small animal dermatology / Karen Helton Rhodes. c2002. Includes bibliographical references and index. ISBN 978-0-8138-1596-1 (pbk. : alk. paper) 1. Dogs–Diseases–Handbooks, manuals, etc. 2. Cats–Diseases–Handbooks, manuals, etc. 3. Exotic animals–Diseases–Handbooks, manuals, etc. 4. Veterinary dermatology–Handbooks, manuals, etc. I. Werner, Alexander H. II. Rhodes, Karen Helton. Five minute veterinary consult clinical companion. III. Title. IV. Title: Five-minute veterinary consult clinical companion. V. Title: Small animal dermatology. [DNLM: 1. Dog Diseases–Handbooks. 2. Skin Diseases–veterinary–Handbooks. 3. Cat Diseases–Handbooks. SF 992.S55] SF992.S55R46 2011 636.089′65–dc22 2010026561 A catalogue record for this book is available from the British Library. Set in 10.5/13 pt Berkeley by Toppan Best-set Premedia Limited 1 2011 This text is dedicated to: ■ Steven, as an expression of gratitude for his continued support in every endeavor. ■ Cameron, may she continue to explore her talent and mastery of the written expression. ■ My parents, Anne and Bill, in appreciation for the gift of an education. ■ And, as always … to Authur I. Hurvitz who, even in his absence, continues to be my mentor, friend, and muse. Karen Helton Rhodes ■ To Rita Werner, our family’ s fi rst author, who always believed in me, and to my mentors who believe in me still. ■ To my siblings who always had faith in me, and to Mike who has faith in me still. ■ And to my children, Jacob and Gregory, who will have faith in me again when they are no longer teenagers. Alexander H. Werner This page intentionally left blank Contents Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .x Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi section 1 Basics chapter 1 Lesion Description/Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 chapter 2 Practical Cytology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 chapter 3 Diagnostic Culture and Identifi cation (Bacterial and Fungal) . . . . . . . . . 27 chapter 4 Obtaining a Diagnostic Biopsy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 chapter 5 Lesional and Regional Differentials . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 chapter 6 Zoonosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 section 2 Allergic and Hypersensitivity Dermatitis chapter 7 Atopic Dermatitis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 chapter 8 Contact Dermatitis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 chapter 9 Eosinophilic Granuloma Complex . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110 chapter 10 Food Adverse Reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 section 3 Endocrine Dermatoses chapter 11 Canine Hyperadrenocorticism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132 chapter 12 Feline Hyperadrenocorticism/Skin Fragility Syndrome . . . . . . . . . . . . . 142 chapter 13 Hypothyroidism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147 chapter 14 Noninfl ammatory Alopecia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 section 4 Immunologic and Autoimmune Disorders chapter 15 Canine Familial Dermatomyositis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172 chapter 16 Discoid (Cutaneous) and Systemic Lupus Erythematosus . . . . . . . . . . 179 chapter 17 Drug Eruption, Erythema Multiforme, and Toxic Epidermal Necrolysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188 chapter 18 Granulomatous Sebaceous Adenitis . . . . . . . . . . . . . . . . . . . . . . . . . . 193 chapter 19 Panniculitis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197 vii viii CONTENTS chapter 20 Pemphigus Complex and Bullous Pemphigoid . . . . . . . . . . . . . . . . . . 203 chapter 21 Sterile Nodular Granulomatous Dermatoses . . . . . . . . . . . . . . . . . . . . 232 chapter 22 Uveodermatologic Syndrome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242 chapter 23 Vasculitis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247 section 5 Infectious Dermatoses chapter 24 Bacterial Folliculitis and Emerging Resistant Pyoderma . . . . . . . . . . . . 256 chapter 25 Dermatophytosis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275 chapter 26 Intermediate and Deep Mycosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283 chapter 27 Leishmaniasis: Protozoan Dermatitis . . . . . . . . . . . . . . . . . . . . . . . . . . 294 chapter 28 Malassezia Dermatitis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298 chapter 29 Mycobacterial Infections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305 chapter 30 Nocardiosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313 chapter 31 Viral Dermatoses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 317 section 6 Neoplasias, Cutaneous/Paraneoplastic Dermatoses chapter 32 Actinic Dermatoses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324 chapter 33 Canine Pre- and Paraneoplastic Syndromes . . . . . . . . . . . . . . . . . . . . 338 chapter 34 Common Skin and Hair Follicle Tumors . . . . . . . . . . . . . . . . . . . . . . . 351 chapter 35 Epitheliotropic Lymphoma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363 chapter 36 Feline Paraneoplastic Syndromes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 375 chapter 37 Histiocytosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 381 chapter 38 Mast Cell Tumors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 388 section 7 Parasitic Disorders chapter 39 Biting and Stinging Insects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398 chapter 40 Demodicosis (Canine and Feline) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413 chapter 41 Sarcoptid Mites (Sarcoptes, Cheyletiella, Notoedres, and Otodectes) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 426 section 8 Selected Topics chapter 42 Acne, Canine and Feline. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 434 chapter 43 Anal Sac Disorders/Perineal Fistulas . . . . . . . . . . . . . . . . . . . . . . . . . . 437 chapter 44 Behavioral or Self-Injurious Dermatoses . . . . . . . . . . . . . . . . . . . . . . . 443 chapter 45 Disorders of Keratinization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 459 chapter 46 Otitis Externa, Media, and Interna . . . . . . . . . . . . . . . . . . . . . . . . . . . 486 chapter 47 Pododermatitis and Claw Disorders . . . . . . . . . . . . . . . . . . . . . . . . . . 515 chapter 48 Superfi cial Necrolytic Dermatitis (Hepatocutaneous Syndrome) . . . . . . 527