Skin Diseases of the Dog and Cat THIRD EDITION Skin Diseases of the Dog and Cat THIRD EDITION NICOLE A. HEINRICH, DVM, DACVD McKeever Dermatology Clinics Eden Prairie and Inver Grove Heights Minnesota, USA MELISSA EISENSCHENK, MS, DVM, DACVD Pet Dermatology Clinic Maple Grove Minnesota, USA RICHARD G. HARVEY, BVSc, DVDF, Dip. ECVD, FRSB, PhD, MRCVS The Veterinary Centre Coventry, UK TIM NUTTALL, BSc, BVSc, PhD, CertVD, CBiol, MRSB, MRCVS Head of Dermatology The Royal (Dick) School of Veterinary Studies The University of Edinburgh Roslin, UK CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2019 by Taylor & Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U.S. Government works Printed on acid-free paper International Standard Book Number-13: 978-1-4822-2596-9 (Hardback) International Standard Book Number-13: 978-1-138-30870-1 (Paperback) This book contains information obtained from authentic and highly regarded sources. While all reasonable efforts have been made to publish reliable data and information, neither the author[s] nor the publisher can accept any legal responsibility or liability for any errors or omissions that may be made. 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Other titles: A colour handbook of skin diseases of the dog and cat Description: Third edition. | Boca Raton : CRC Press, [2018] | Preceded by A colour handbook of skin diseases of the dog and cat / Tim Nuttall, Richard G. Harvey, Patrick J. McKeever. 2nd ed. c2009. | Includes bibliographical references and index. Identifiers: LCCN 2017033713 (print) | LCCN 2017035548 (ebook) | ISBN 9781315118147 (Master eBook) | ISBN 9781138308701 (pbk. : alk. paper) | ISBN 9781482225969 (hardback : alk. paper) Subjects: LCSH: Dogs--Diseases. | Cats--Diseases. | Veterinary dermatology. | MESH: Skin Diseases--veterinary | Dog Diseases | Cat Diseases Classification: LCC SF992.S55 (ebook) | LCC SF992.S55 M37 2018 (print) | NLM SF 992.S55 | DDC 636.7/08965--dc23 LC record available at https://lccn.loc.gov/2017033713 Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com and the CRC Press Web site at http://www.crcpress.com CONTENTS v Preface xi Acknowledgements xiii Treatment recommendations and professional responsibilities xv CHAPTER 1 BASICS 1 Terminology used in the description of dermatological lesions 1 Dermatological sampling techniques 8 Dermatological history and physical exam 12 CHAPTER 2 PRURITIC DERMATOSES 13 Acral lick dermatitis (acral lick granulomas) 13 Behavioural dermatoses 15 Atopic dermatitis in dogs 18 Malassezia dermatitis (cutaneous yeast infection) 30 Urticaria (hives) 33 Anal sac disease (anal sac impaction, sacculitis or abscessation) 34 Contact dermatitis (irritant contact dermatitis, allergic contact dermatitis) 36 Epitheliotrophic lymphoma (mycosis fungoides, cutaneous T-cell lymphoma, Sézary’s syndrome) 38 Feline hypersensitivity dermatitis (feline allergic dermatitis, feline atopic dermatitis) 41 Feline Demodex gatoi infestation 48 Notoedric mange 49 Cheyletiella mite infestation 50 Fleas and flea allergic dermatitis (flea bite hypersensitivity) 52 Sarcoptic mange 56 Harvest mite infestation (trombiculiasis, chiggers) 59 Pediculosis (lice) 61 Neurogenic dermatoses (including feline orofacial pain syndrome, trigeminal neuropathy, feline idiopathic ulcerative dermatosis, syringomyelia, sensory neuropathy and tail dock neuroma) 63 vi Contents CHAPTER 3 CRUSTING DERMATOSES 65 General approach to papules, pustules and crusts 65 Surface and superficial pyoderma 65 Canine acne (chin and muzzle folliculitis and furunculosis) 75 Feline acne 77 Fly and mosquito bite dermatitis 79 Pemphigus foliaceus 81 Trichophyton mentagrophytes dermatophytosis 85 Idiopathic ear margin vasculitis (proliferative thrombovascular necrosis of the pinna) 85 Solar dermatitis (actinic keratosis) 87 Feline squamous cell carcinoma in situ 89 Facial dermatitis of Persian and Himalayan cats 90 Feline thymoma-associated dermatosis 91 CHAPTER 4 ALOPECIC DERMATOSES 93 Non-pruritic alopecia 93 Alopecia X 95 Cyclical flank alopecia (seasonal flank alopecia, flank alopecia, recurrent flank alopecia) 97 Telogen and anagen defluxion 99 Hypothyroidism 100 Hyperadrenocorticism in dogs and cats (Cushing’s disease) 104 Feline paraneoplastic alopecia 110 Acquired pattern alopecia (pattern baldness, follicular miniaturisation) 111 Black hair follicular dysplasia 112 Colour-dilution alopecia (colour-mutant alopecia, blue Doberman or blue dog syndrome) 113 Dermatophytosis 115 Feline demodicosis 121 Canine demodicosis 122 Alopecia areata 126 Tail gland hyperplasia (stud tail) 127 Injection site alopecia 128 Postclipping alopecia 130 Topical corticosteroid reaction 131 CHAPTER 5 DERMATOSES OF ABNORMAL KERATINISATION 133 Topical therapies for seborrhoea 133 General approach to keratinisation disorders 133 Ichthyosis 134 Sebaceous adenitis 135 Contents vii Zinc-responsive dermatosis 137 Leishmaniasis 139 Exfoliative cutaneous lupus erythematosus of the German Short-haired Pointer 144 Vitamin A-responsive dermatosis 145 Idiopathic keratinisation defects (primary seborrhoea) 146 Canine ear margin seborrhoea 150 Nasal and digital hyperkeratosis 151 Callus formation 152 Schnauzer comedo syndrome 154 Cutaneous horn 155 Spiculosis 156 CHAPTER 6 ULCERATIVE DERMATOSES 157 General approach to ulcerative dermatoses 157 Feline idiopathic ulcerative dermatitis 157 Feline cutaneous herpesvirus and calicivirus infections 159 Feline cowpox infection 160 Pemphigus vulgaris 162 Bullous pemphigoid 163 Mucous membrane pemphigoid 164 Mucocutaneous pyoderma 165 Epidermolysis bullosa acquisita 167 Vasculopathy of Greyhounds (cutaneous and renal glomerular vasculopathy, Alabama rot, Greenetrack’s disease) 168 Vesicular cutaneous lupus erythematosus of the Shetland Sheepdog and Collie 170 Systemic lupus erythematosus 171 Superficial necrolytic dermatitis (diabetic dermatopathy, hepatocutaneous syndrome, necrolytic migratory erythema and metabolic epidermal necrosis) 174 German Shepherd dog pyoderma 177 Decubital ulcers (pressure sores) 179 Mucocutaneous lupus erythematosus 180 Vasculitis and vasculopathy 182 Erythema multiforme complex 185 CHAPTER 7 DRAINING TRACTS 189 General approach to draining tracts 189 Pansteatitis (yellow fat disease) 189 Feline mycobacterial infections 190 Postgrooming furunculosis 193 Deep pyoderma (furunculosis) 195 viii Contents Canine mycobacteriosis (canine leproid granuloma and opportunistic [atypical] mycobacterial infections) 198 Nocardiosis/Actinomycosis 200 Sporotrichosis 202 Blastomycosis 204 Saprophytic deep fungal infections (eumycotic