Moriello's Small Animal Dermatology Volume 1, Fundamental Cases and Concepts

Self-Assessment Color Review, Second Edition

Darren Berger

• Publisher: CRC Press
• Year: 2019
• Print ISBN:
  9780815371632
• eBook ISBN:
  9780429524271
• Topic: Medicine
• Subtopic: Dermatology

Karen Moriello's seminal book has been completely updated in an effort to create a true two-volume set highlighting fundamental and advanced concepts. This revised fundamental edition includes all new cases and nearly 300 new images. The guide uses a case-based format to deliver a general overview of dermatology of the dog and cat, providing a reference that mirrors the way veterinarians will encounter different scenarios at random in real-life practice. It uses self-assessment problems to review the most common skin diseases encountered every day, plus some more obscure diseases that a veterinarian will face.

1 & 2: Questions

1. A 16-week-old female mixed breed puppy presented with a complaint of severe hair loss and “scabs.” On physical exam, diffuse alopecia and erythema with the presence of papules, pustules, and crusts were appreciated (Figure 1a, b) along with a generalized lymphadenopathy. Given the clinical presentation, you are suspicious this puppy has generalized demodicosis.

Figure 1a

Figure 1b

What are the various diagnostic techniques that can be used to demonstrate the presence of mites in this patient?

2. A 6-year-old castrated male cocker spaniel from the Midwest region of the United States presented for examination of progressive nonhealing wounds on the skin (Figure 2a). The lesions were first observed 2 months ago and have failed to respond to prior antimicrobial therapy with cephalexin. The patient is also reported to be anorexic with noticeable weight loss. On physical examination, there were multiple 1–2 cm diameter-crusted nodules, which were moderately painful on palpation. Removal of the crust revealed ulcerated draining tracts with a thick purulent exudate that was easily expressed. In addition, there was generalized lymphadenopathy and increased respiratory noise on auscultation. The patient had a normal rectal temperature but was noted to be quiet and depressed during examination.

Figure 2a

i. What are the differential diagnoses for this patient?

ii. What are the most logical first diagnostic steps in this patient?

iii. Assuming the cause of the lesions and lymphadenopathy has not been identified, what other diagnostic tests should be performed?

1 & 2: Answer

1. Skin scraping is considered the gold standard for demonstrating the presence of Demodex mites. Historically, authors have discussed the need for “deep scrapings” (creating capillary bleeding), but this may not be needed and can result in unneeded cutaneous trauma. The author believes the actual important component of the technique is to massage or squeeze the area to be sampled prior to scraping, not the depth of the scraping. Skin scrape samples should be obtained by first clipping or parting the hair coat, squeezing the skin in an effort to extrude mites from the follicle, placing mineral oil on the skin at the squeezed site, then with a scapel blade or spatula at roughly 90° to the skin gently scraping the skin. Next, in a scraping and scooping motion collect the mixture of oil and skin debris and place it on a clean glass slide that should then have a glass coverslip placed over the mixture. Finally, examine the slide microscopically under 4× or 10× power. Trichography may also be used, especially for collection of samples from the paws or periocular region. A downside of this technique is that it is not as sensitive as skin scraping. When used, several sites should be sampled ensuring an adequate number of hairs are collected to minimize the chance of a false-negative result. Examination of exudate from pustules or draining lesions may reveal the presence of mites (Figure 1c). The use of a clear acetate tape impression can also be effective in demonstrating the presence of Demodex mites (Pereira et al., 2012). This technique specifically highlights the importance of properly squeezing the skin prior to sampling. Finally, mites may also be demonstrated via biopsy, but this is usually not required, and detection by this method is usually accidental when the clinician did not initially suspect demodicosis.

Figure 1c

2. i. The dog’s dermatologic problem is multiple draining nodules. Differential diagnoses for nonhealing draining nodules in a dog are somewhat age dependent but would include undiagnosed demodicosis resulting in furunculosis, infectious granulomas (bacterial, mycobacterial, fungal), juvenile cellulitis, adverse drug eruption, sterile nodular dermatoses (i.e., sterile nodular panniculitis), foreign-body reaction, and neoplasia. The concurrent signs of systemic illness (anorexia, depression, weight loss, and lymphadenopathy) suggest that the skin lesions are secondary to an underlying systemic infection, autoimmune disease, or neoplasia.

ii. The first diagnostic steps in a patient such as this should include skin scrapings to rule out demodicosis; impression smears to look for infectious agents; and lymph node aspirates to determine if the lymphadenopathy is reactive, neoplastic, or infectious. These initial diagnostic tests are simple to perform and with practice can be easily interpreted by the veterinarian. In many cases, these simple first-line diagnostics can provide a definitive diagnosis and avoid unneeded patient costs.

iii. If cytologies and aspirates fail to reveal a causative agent, next-level diagnostics involve skin biopsies for dermat...

Table of contents

• Cover
• Half Title
• Series Page
• Title Page
• Copyright Page
• Dedication
• Broad classification of cases
• Preface
• Acknowledgments
• Author
• 1 & 2: Questions
• 3 & 4: Questions
• 5 & 6: Questions
• 7 & 8: Questions
• 9 & 10: Questions
• 11 & 12: Questions
• 13 & 14: Questions
• 15 & 16: Questions
• 17 & 18: Questions
• 19: Questions
• 20: Questions
• 21 & 22: Questions
• 23 & 24: Questions
• 25 & 26: Questions
• 27, 28, & 29: Questions
• 30 & 31: Questions
• 32: Questions
• 33: Questions
• 34: Questions
• 35 & 36: Questions
• 37 & 38: Questions
• 39 & 40: Questions
• 41, 42, & 43: Questions
• 44 & 45: Questions
• 46 & 47: Questions
• 48, 49, & 50: Questions
• 51, 52, & 53: Questions
• 54 & 55: Questions
• 56: Questions
• 57 & 58: Questions
• 59 & 60: Questions
• 61: Questions
• 62: Questions
• 63, 64, & 65: Questions
• 66 & 67: Questions
• 68 & 69: Questions
• 70: Questions
• 71: Questions
• 72 & 73: Questions
• 74 & 75: Questions
• 76: Questions
• 77 & 78: Questions
• 79, 80, & 81: Questions
• 82, 83, & 84: Questions
• 85, 86, & 87: Questions
• 88, 89, & 90: Questions
• 91 & 92: Questions
• 93 & 94: Questions
• 95, 96, 97, & 98: Questions
• 99, 100, & 101: Questions
• 102: Questions
• 103: Questions
• 104 & 105: Questions
• 106: Questions
• 107 & 108: Questions
• 109 & 110: Questions
• 111: Questions
• 112 & 113: Questions
• 114, 115, & 116: Questions
• 117, 118, 119, & 120: Questions
• 121 & 122: Questions
• 123: Questions
• 124: Questions
• 125: Questions
• 126: Questions
• 127, 128, & 129: Questions
• 130: Questions
• 131 & 132: Questions
• 133 & 134: Questions
• 135, 136, & 137: Questions
• 138: Questions
• 139: Questions
• 140, 141, 142, & 143: Questions
• 144 & 145: Questions
• 146: Questions
• 147 & 148: Questions
• 149: Questions
• 150, 151, & 152: Questions
• 153, 154, & 155: Questions
• 156: Questions
• 157: Questions
• 158 & 159: Questions
• 160 & 161: Questions
• 162 & 163: Questions
• 164 & 165: Questions
• 166 & 167: Questions
• 168, 169, & 170: Questions
• 171 & 172: Questions
• 173 & 174: Questions
• 175, 176, & 177: Questions
• 178, 179, & 180: Questions
• 181: Questions
• 182: Questions
• 183 & 184: Questions
• 185 & 186: Questions
• 187 & 188: Questions
• 189 & 190: Questions
• 191 & 192: Questions
• 193: Question
• 194: Questions
• 195 & 196: Questions
• 197 & 198: Questions
• 199 & 200: Questions
• 201 & 202: Questions
• 203: Questions
• 204: Question
• 205 & 206: Questions
• 207: Questions
• References
• Index