Ebook Complex clinical cases in small animal dermatology: Part 1

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Part 1 book "Complex clinical cases in small animal dermatology" includes content: Generalised partial alopecia with scaling in a dog; alopecic, ulcerated and erythematous mass-like lesion on the tarsal region in a cat; diagnostic approach to multifocal alopecia in a dog using dermoscopy as a new tool; ulcerative dermatitis in a dog; mucocutaneous ulcerative dermatitis in a dog, multifocal alopecia and diffuse, severe exfoliative dermatitis in a cat; generalised pustular dermatitis in a dog; multiple pigmented lesions in a cat.

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in n Sm mall An nim mal Derm mattolo ogyy Carla Dedola Giordana Zanna
COMPLEX Clinical Cases in Small Animal Dermatology
Copyright © 2022 Grupo Asís Biomedia, SL Plaza Antonio Beltrán Martínez n.º 1, planta 8 - letra I (Centro empresarial El Trovador) 50002 Zaragoza - Spain First printing: January 2022 Illustrator: Jacob Gragera Artal ISBN: 978-84-18339-32-5 DL: Z 1772-2021 Design, layout and printing: Grupo Asís Biomedia, SL www.grupoasis.com info@grupoasis.com All rights reserved. Any form of reproduction, distribution, publication or transformation of this book is only permitted with the authorisation of its copyright holders, apart from the exceptions allowed by law. Contact CEDRO (Spanish Centre of Reproduction Rights, www.cedro.org) if you need to photocopy or scan any part of this book (www.conlicencia.com; 0034 91 702 19 70/0034 93 272 04 47). Warning: Veterinary science is constantly evolving, as are pharmacology and the other sciences. Inevitably, it is therefore the responsibility of the veterinary surgeon to determine and verify the dosage, the method of administration, the duration of treatment and any possible contraindications to the treatments given to each individual patient, based on his or her professional experience. Neither the publisher nor the author can be held liable for any damage or harm caused to people, animals or properties resulting from the correct or incorrect application of the information contained in this book.
COMPLEX Clinical Cases in Small Animal Dermatology Carla Dedola Giordana Zanna
THE AUTHORS V THE AUTHORS CARLA DEDOLA Dr. Carla Dedola graduated in Veterinary Medicine from the Uni- versity of Sassari (Italy) in 2001. After fulfilling her degree, she worked as a general practitioner in a private Veterinary Clinic in Monza (Italy), starting to develop her passion in small animal dermatology. In 2007, she obtained a position as resident in Dermatology at the Royal (Dick) School of Veterinary Studies at the University of Edinburgh (Scotland). In 2010, she sustained and passed the European College exam in Veterinary Dermatol- ogy becoming a European Diplomate in Veterinary Dermatology. She has been secretary of the Italian Society of Small Animal Dermatology (SIDEV) in Italy from 2014 to 2019. Since 2011, she has been working as freelance in Sardinia (Italy) collabo- rating with numerous Veterinary Clinic over the territory. She is the director and the scientific mentor for dermatological courses organized by the Italian Scientific Society of Veterinary Medicine for small animal (SCIVAC). GIORDANA ZANNA Dr. Giordana Zanna graduated in Veterinary Medicine from the University of Bari (Italy) in 2000. After working in general prac- tice in Italy and doing externships at Universities of Liverpool and Bristol (UK), she undertook a residency in Veterinary Der- matology at Universitat Autònoma de Barcelona (UAB) in Spain, gaining her Diploma of the European College of Veterinary Der- matology in 2010. At the same Institution, she fulfilled her PhD studies on the pathogenesis of mucinosis-hyaluronosis in Shar Pei dogs in 2010. Vice-president of the Italian Society of Small Animal Dermatology (SIDEV), secretary of the Italian Companion Animal Veterinary Association (SCIVAC), she is the director and scientific mentor of the Italian course of Dermatology. Giordana now works at Instituto Veterinario di Novara (Italy) as a private practice dermatology specialist, and she regularly provides lec- tures in national courses both in Italy and Spain and gives talks at international conferences. She has written several articles published in national and international journals and she also enjoys research with a special interest in non-invasive diagnostic techniques such as dermoscopy.
VI COMPLEX CLINICAL CASES IN SMALL ANIMAL DERMATOLOGY FOREWORD After 40 years of profession, I am totally convinced that the essential requirements to provide excellent clini- cal care for patients is a problem-oriented approach and a commitment to lifelong learning. All we know that clinical problems are not always straightforward to solve, and animals may present with a number of different clinical signs. Traditional methods of teaching often do not meet the criteria for contextual learning. In contrast problem-based learning (PBL) mimics real life situations to stimulate learning, the integration of knowledge and lifelong learning skills. Within veterinary medicine, clinical cases lend themselves easily to this method of learning. It is impor- tant that genuine clinical cases are selected because these tend to be complex, with frequently unpredictable outcomes. I had the chance to work with Dr Dedola and Dr Zanna in several postgraduate veterinary courses and I had the opportunity to appreciate their enthusiasm and ability in teaching dermatology and problem-oriented approach. With great pleasure I have found the same enthusiasm and ability in this book. The reader is transported here across several clinical scenarios that are excellent examples of “real-life” in veterinary dermatology. Fabia Scarampella DVM, MSc, Dipl. ECVD
yÝĄKŚÝĄAӕĀĄKy:K VII PREFACE This book aims to present a range of complex dermatological clinical cases in both dogs and cats. “Complex” means all those situations for which it is not easy or straightforward to find a solution or an answer. Starting from this point, the authors selected challenging dermatological cases for which reaching a final diagnosis was not as simple or linear as in other situations. Difficulties might have been arisen from the unusual clinical presentation, from unexpected results of the diagnostic tests or from the lack of positive answer to a therapeutic protocol that was considered adequate for that specific case. The complexity of the cases might derive from the patient, its genotype or phenotype, from its immunological status, from the presence of comorbidity or simply from the fact that the clinicians won’t expect that specific disease in that patient for different reasons (i.e. not predisposed breed, unusual age). The readers will go through the development of the cases following the thoughtful way explained by the authors themselves. Each case has a problem-based approach, incorporating its respective history, physical and der- matological examinations, diagnostic tests and results, treatment and outcome. The authors will end up with some considerations as well as the key elements for a better interpretation of each specific case. The authors
VIII COMPLEX CLINICAL CASES IN SMALL ANIMAL DERMATOLOGY TABLE OF CONTENTS CASE 1. Generalised partial alopecia with scaling Ǟȁ‫ٶ‬ƊƮȌǐ ....................................................................................................................................................................... 1 CASE 2. ǶȌȯƵƧǞƧ‫ة‬ɐǶƧƵȲƊɈƵƮƊȁƮ‫ٶ‬ƵȲɯɈǘƵǿƊɈȌɐȺ ǿƊȺȺٌǶǞǲƵǶƵȺǞȌȁȌȁɈǘƵɈƊȲȺƊǶȲƵǐǞȌȁǞȁ‫ٶ‬ƊƧƊɈ ........... 9 CASE 3. (ǞƊǐȁȌȺɈǞƧƊȯȯȲȌƊƧǘɈȌǿɐǶɈǞǏȌƧƊǶƊǶȌȯƵƧǞƊ Ǟȁ‫ٶ‬Ɗ‫ٶ‬ƮȌǐɐȺǞȁǐƮƵȲǿȌȺƧȌȯɯƊȺƊȁƵɩɈȌȌǶ........................ 17 CASE 4. ÇǶƧƵȲƊɈǞɨƵƮƵȲǿƊɈǞɈǞȺǞȁƊƮȌǐ .......................................................................... 25 CASE 5. wɐƧȌƧɐɈƊȁƵȌɐȺɐǶƧƵȲƊɈǞɨƵƮƵȲǿƊɈǞɈǞȺ in a dog ....................................................................................................................................................................... 33 CASE 6. wɐǶɈǞǏȌƧƊǶƊǶȌȯƵƧǞƊƊȁƮƮǞǏǏɐȺƵ‫ة‬ ȺƵɨƵȲƵƵɮǏȌǶǞƊɈǞɨƵƮƵȲǿƊɈǞɈǞȺǞȁƊƧƊɈ ............................................... 41 CASE 7. JƵȁƵȲƊǶǞȺƵƮȯɐȺɈɐǶƊȲƮƵȲǿƊɈǞɈǞȺǞȁƊƮȌǐ ........................... 51 CASE 8. wɐǶɈǞȯǶƵȯǞǐǿƵȁɈƵƮǶƵȺǞȌȁȺǞȁƊƧƊɈ ................................................. 61 CASE 9. JƵȁƵȲƊǶǞȺƵƮƵɮǏȌǶǞƊɈǞɨƵƮƵȲǿƊɈǞɈǞȺǞȁƊƮȌǐ.................... 69 CASE 10. ȺƵɨƵȲƵƵɮɐƮƊɈǞɨƵƮƵȲǿƊɈǞɈǞȺǞȁƊƧƊɈ........................................ 79 CASE 11. mǞƧǘƵȁȌǞƮƮƵȲǿƊɈǞɈǞȺǞȁƊƮȌǐ........................................................................... 87
TABLE OF CONTENTS IX CASE 12. Multiple subcutaneous ulcerated nodules Ǟȁ‫ٶ‬ƊƮȌǐ ....................................................................................................................................................................... 95 CASE 13. wɐǶɈǞǏȌƧƊǶƊǶȌȯƵƧǞƊǞȁ‫ٶ‬ƊƮȌǐ................................................................................... 103 CASE 14. yƊȺƊǶȯǶƊȁɐǿƵȲȌȺǞɨƵٌɐǶƧƵȲƊɈǞɨƵƮƵȲǿƊɈǞɈǞȺ‫ٶ‬ in a dog ....................................................................................................................................................................... 113 CASE 15. RɯȯƵȲǲƵȲƊɈȌɈǞƧƧȲɐȺɈɯƮƵȲǿƊɈǞɈǞȺǞȁ‫ٶ‬Ɗ‫ٶ‬ȯɐȯȯɯ ............. 121 CASE 16. yȌƮɐǶƊȲɐǶƧƵȲƊɈǞɨƵƮƵȲǿƊɈǞɈǞȺǞȁƊƧƊɈ ......................................... 131 CASE 17. ǶȌȯƵƧǞƊƊȁƮɐǶƧƵȲƊɈǞɨƵƮƵȲǿƊɈǞɈǞȺǞȁƊƮȌǐ................ 139 CASE 18. Generalised alopecia with spontaneous ǘƊǞȲȲƵǐȲȌɩɈǘǞȁ‫ٶ‬Ɗ‫ٶ‬ƮȌǐ......................................................................................................... 149 CASE 19. ǶȌȯƵƧǞƊƊȁƮƵɮǏȌǶǞƊɈǞɨƵƮƵȲǿƊɈǞɈǞȺ in an atopic dog.................................................................................................................................... 157 CASE 20. 0ɮǏȌǶǞƊɈǞɨƵƮƵȲǿƊɈǞɈǞȺƊȁƮȌƵƮƵǿƊɈȌɐȺ ȺɩƵǶǶǞȁǐǞȁƊȁǞǿǿɐȁȌƧȌǿȯȲȌǿǞȺƵƮƧƊɈ.......................... 167 REFERENCES .......................................................................................................................................................................................... 175
CASE 1 {KÇKĄ¸ČKAĀĄě¸ ¸ÝĀK:ŚěČ:¸Ç{ ÇԝAÝ{
COMPLEX CLINICAL CASES IN SMALL ANIMAL DERMATOLOGY
3 CASE 1. GENERALISED PARTIAL ALOPECIA WITH SCALING IN A DOG SIGNALMENT ■ Species: dog ■ Breed: Pomeranian ■ Age: 3-year-old ■ Sex: female ■ Lifestyle: indoor INTRODUCTION of small white adherent scales and hair casts on the trunk, the head and both ear pinna (Fig. 2a–c). This case represents an opportunity for every clinician to recall the importance of following step by step a correct diagnostic Differential diagnosis approach, which is fundamental to confirm or dismiss a clinical Based on the signalment, history and clinical findings, the differ- suspicion. The diagnosed disease is not particularly uncommon ential diagnosis lists as follow: or difficult to recognize, but it could have been missed or con- ■ Idiopathic granulomatous sebaceous adenitis. fused with another condition presenting similar clinical aspects ■ Leishmaniosis (see Box 1). much more commonly described in the reported dog breed. ■ Hair cycle arrest (alopecia X). ■ Demodicosis. ■ Generalised dermatophytosis. CLINICAL HISTORY The dog began to show hair loss and presence of scales approx- imately 6 months before consultation. The systemic antibiotic treatment prescribed by the referring veterinarian, amoxicil- lin and clavulanate at a dosage of 15 mg/kg (BW) two times daily for 14 days, did not help in the hair regrowth. The hair loss started from the head and extended to the trunk, the tail and the extremities. EXAMINATION {KÇKĄ¸ĀťČ:¸KŤÃÇěÝÇ No abnormalities were detected. DERMATOLOGICAL EXAMINATION The examination revealed a diffuse partial alopecia and lack of Figure 1. Generalised partial alopecia, especially evident on the trunk and secondary hairs. Poor, dry and dull hair coat was also observed the caudal aspect of the legs (arrow). Secondary hairs are lacking, with a (Fig. 1). A closer observation was helpful to identify the presence lusterless hair coat.
4 COMPLEX CLINICAL CASES IN SMALL ANIMAL DERMATOLOGY a b c Figure 2. Small adherent scales on the head (a) and scales on the pinna clumping together with many hair shafts (b and c). DIAGNOSTIC TESTS RESULTS During this case, it was decided to perform: ■ Microscopic hair examination: keratin debris accumula- ■ Microscopic hair examination: this is considered the most tion on hair shaft with hairs often clumping together was helpful test to observe hair shaft and hair bulb in case of observed; those findings are compatible with the so-called suspicion of a disease affecting those structures. Moreover, hair casts (Fig. 3; see the key elements of the case). The although this is not considered the gold standard, this test majority of the hair bulbs were in the telogen (hair cycle makes possible to identify Demodex mite and fungal hyphae or spores. ■ Deep skin scraping: it is considered the gold standard test for the diagnosis of demodicosis. The material was collected and placed on a slide with some mineral oil and a coverslip on top. It was examined with the low-power objectives of the microscope (4× and 10×). ■ Fungal culture: some hairs and scales were collected by plucking and scraping and send to a specialised laboratory in order to perform a fungal culture. As part of an exhaustive physical examination, and because leishmaniosis was one of the considered differential diagnosis, the following further tests were performed: ■ Complete blood count (CBC). ■ Serum biochemical profile. ■ Serological immunofluorescence antibody test (IFAT) for Leishmania antibodies. Multiple skin biopsies were planned in case a diagnosis was Figure 3. Numerous keratinosebaceous debris surrounding hair shaft not reached after performing the previously cited tests. (hair casts).
:ČKіӝ{KÇKĄ¸ČKAĀĄě¸¸ÝĀK:ŚěČ:¸Ç{ÇԝAÝ{ 5 arrest) phase, although some hairs in anagen (active hair prominent follicular keratoses were also observed. Seba- growth) phase were also observed. ceous glands were not present and a lymphocytic and histio- ■ Skin scrapings were negative for the presence of Demodex cytic inflammatory infiltrate was present on their behalf in mites and fungal elements. some hair follicle compound (Fig. 4a–c). ■ Fungal culture did not identify any pathological growth. ■ Blood analysis. CBC and biochemistry profile were unre- markable and Leishmania antibody titer was negative. All the findings were consistent with a final ■ On histopathological skin samples, the epidermis showed diagnosis of idiopathic granulomatous the presence of a lamellar orthokeratotic hyperkeratosis with sebaceous adenitis. a basketwave apperance. Multiple follicular plugging with a b c d Figure 4. Dermatopathological findings with hematoxylin and eosin stain (H&E) (10×–40×). Epidermal basketweave, lamellar orthokeratotic hyperkeratosis (a and b; see black arrow in b) and multifocal follicular keratoses (b and c; see red arrow), together with a complete absence of sebaceous glands and occasional lymphocytic and histiocytic inflammatory infiltrate presence on their behalf (b and c; see green arrow). Inflammatory infiltrate present on behalf of sebaceous gland (d). Images courtesy of Dr. C. Brachelente (University of Veterinary Medicine, Perugia. Italy).
6 COMPLEX CLINICAL CASES IN SMALL ANIMAL DERMATOLOGY TREATMENT AND OUTCOME CONSIDERATION The dog was initially treated with oral cyclosporine A (CsA) at Although no specific diagnostic difficulties were found, some a dosage of 5 mg/kg (BW) once daily, together with shampoo further considerations should be taken into account. Firstly, the containing sulphur, zinc gluconate, lactic and salicylic acid once clinical presentation of the dog, together with the breed, could weekly and soak with propylene glycol diluted by 50 % with have misled the clinician towards a diagnosis of hair follicle water once daily. arrest (alopecia X), highlighting the importance of an adequate After 2 months of treatment, a marked improvement was performance of the diagnostic procedures in order to confirm a noticed: hairs were growing back and scales were reduced by clinical suspicion. Another thing to point out it is the necessity 75 %. The CsA was given at the same dosage but every 48 to carry out a careful and close evaluation of the skin lesions hours as opposed to the initial daily treatment. Rechecks were and their distribution. In fact, hair casts as well as the involve- planned every 30–60 days, unless needed differently. ment of the head and the ears have not been described to be The dog showed a partial relapse during the maintenance present as typical lesions in dogs suffering from hair follicle treatment, which consisted of a long term dosage of 5 mg/kg arrest. All these aspects have therefore guided the authors in (BW) of CsA every 72 hours, together with diluted propylene the selection of the appropriate diagnostic test to reach an early glycol soak every other day and shampoo once weekly. The diagnosis and avoid unnecessary tests. general aspect of the hair coat was improved although it never returned completely to normal; the scaling dermatitis was well controlled but it relapsed occasionally when the owner tended to The clinical presentation of the dog together neglect the topical treatment. with the breed could have misled the clinician towards a diagnosis of hair follicle arrest. THE KEY ELEMENTS OF THE CASE Hair casts are accumulations of keratin debris that adhere to the hair shaft extending above the follicular ostia (Fig. 5). Hair casts are considered a primary lesion in disorders of cornification, especially in sebaceous adenitis, but can be also found in demodicosis and dermatophytosis. In this case, if hair casts had not been present, hair cycle arrest would have probably been the first differential due to the breed of the dog (Fig. 6). Figure 5. Dermoscopic images showing hair casts on hair shaft. Figure 6. Chow Chow with hair follicle arrest (alopecia X). Hair coat is poor and there is complete lack of secondary hairs. Hyperpigmented alopecic multifocal areas are visible on the neck, the flank and the thigh.
:ČKіӝ{KÇKĄ¸ČKAĀĄě¸¸ÝĀK:ŚěČ:¸Ç{ÇԝAÝ{ 7 AÝĀě:{ĄÇĩ¸ÝÃěÝĩČČK9:KÝĩČAKÇěČ 9ĄKyAKČ:ĄĀěÝÇÝyěKAČKČK TREATMENT Idiopathic granulomatous sebaceous adenitis is a disease charac- Mild cases of sebaceous adenitis can be treated with: terised by an immunological reaction, most probably due to natu- ■ Topical treatment using keratolytic shampoo containing ral cell-mediated immunity, directed against the dog´s sebaceous ingredients such us sulphur or salicylic acid together with glands, which can result in their partial or complete destruction. emollient and hygroscopic rinses containing glycerine, urea, Idiopathic granulomatous sebaceous adenitis is an uncommon colloidal oatmeal, sodium lactate and lactic acid. disease in dogs and rare in cats. The age of onset can vary widely, ■ Daily spray or rinses with propylene glycol diluted with water from young to middle-aged dogs, and there is a reported breed to 50–75 % which has been demonstrated to work well in predilection for standard poodles, Akitas, Samoyeds and Vizslas, controlling the clinical lesions. although mongrels and other breeds can be affected as well. ■ Essential fatty acids omega-6 and omega-3 given orally have Clinical lesions can be limited to the presence of scales and been shown to be helpful in managing all cases. For this rea- partial alopecia, especially in the early phase, or can occur in son, they should always be part of the therapeutic protocol. more severe forms showing prominent hair casts, extended alo- pecic areas and signs of secondary infections, possibly caused In more severe cases, a systemic treatment is necessary: by bacteria and/or yeast. The hair coat is poor and dull, and it ■ Ciclosporin A (CsA) is nowadays the treatment of choice, can become straight from curly in poodles. Otitis externa can given at a dose of 5 mg/kg/day until a 50 to 75 % of improve- be present and, in some cases, it can appear as a unique early ment have been reached, and then reduced to the most effi- clinical sign. The lesions are initially distributed on the dorsum cacious dosage. and the head; ear pinnae are also typically involved (Fig. 7). ■ Natural vitamin A at a dose of 10,000 to 30,000 IU/day has Finally, they tend to generalise over time. showed a good response in 80 % of patients treated. Principal differential diagnosis includes demodicosis, derma- ■ Cases not responding to CsA can be treated with synthetic tophytosis, follicular dysplasia and, in endemic areas, leishmani- retinoids (i.e. isotretinoin 0.8–3.5 mg/kg/day or etretinate osis. The diagnostic confirmation can be reached with the aid of 0.7–1.8 mg/kg/day). However, the high costs and the serious histopathology: in the early phase, a granulomatous to pyogranu- potential side effects make these drugs difficult to be used. lomatous inflammatory infiltrate targeting the sebaceous glands with follicular keratoses can be observed; in late stages of disease, The aim of the therapy is to keep the disease under control. a complete destruction of these glands together with follicular Rarely dogs go back to normal and many of them show relapse atrophy and scant inflammatory infiltrate may be likely to occur. even when receiving therapy. It could be convenient to advise systemic treatment also in mild initial cases, as this seems that this may be the only way of getting back functional sebaceous glands. Figure 7. Idiopathic granulomatous sebaceous adenitis lesions are distributed initially on the dorsum and the head. Ear pinnae are typically involved (lesion distribution in the reported case).
8 COMPLEX CLINICAL CASES IN SMALL ANIMAL DERMATOLOGY Box 1. Sebaceous adenitis due to canine leishmaniosis Sebaceous glands can be involved and destroyed in other dermal inflammatory processes apart from idiopathic sebaceous ade- nitis. Differentiation of sebaceous adenitis due to canine leishmaniosis from the idiopathic form may be particularly challenging (see picture in Box 1). Direct identification of the Leishmania amastigotes in the tissue can be difficult, especially if their number is low. On histo- pathological examination, nodular and diffuse dermal infiltrate and epidermal and subepidermal lesions have been reported to be present in sebaceous adenitis secondary to canine leishmaniosis, while in the idiopathic form, the inflammation is generally restricted to the sebaceous glands and it is associated with epidermal hyperkeratosis and follicular keratosis. a b